The Information Overload Hour

INFORMATION----THE FINAL FRONTIER:

As much as we all love our bikes..........especially when we're challenged by the many and varied tasks necessary to repair, rebuild, or maintain them (after all, this is what makes a 'biker' and a "guy who rides motorcycles" different) ....... sometimes it can be more of a challenge to find the proper, honest, experienced advice and know-how necessary to proceed with such tasks, than it is to actually perform such tasks!

Welcome to the Information Overload Hour..........where all of your best laid plans and dreams can eventually come true, but you're going to have to march----upside down on your hands while juggling B-B's with your toes----thru heck and high water just to find the real, solid info that you'll need (besides the parts, the tools, and the cold beers) to get the job done right, the first time around.

Enough of that nonsense, that's what we say!


So to make your life a little bit easier, and much more successful, we've compiled a list of some of the most useful HOW-TO threads that can give you ideas, lend a (virtual) helping hand, and allow you to spend more of your time with a torque wrench in your hands rather than risking carpal-tunnel syndrome from mindless hours of searching, searching, and more searching for the real answers that you need.

NOTE: the following guides (and all others, for that matter) are absolutely no substitute (none, zip, zero, zilch) for having the proper tools necessary to accomplish any task properly, and the most important tool that you can have in your tool-chest is a factory or aftermarket Workshop Manual for your specific bike. Don't short-change yourself and potentially risk life and limb by being penny-wise and pound-foolish: beg, borrow, or steal the correct manual for your bike, and live happily ever after........


And here are the 3 rules you should always follow whenever trying to troubleshoot anything:

 

KNOW THY RIDE:


- FRAME AND MODEL AND VIN NUMBERS, OH MY!!!:

http://www.xjbikes.com/forums/index.php?threads/tech-topic-model-id-and-vins.14577/



- COOL HAND LUKE: GETTING YOUR MIND RIGHT:

a/k/a THE USED BIKE PURCHASING SURVIVAL GUIDE:

Always remember the ancient wisdoms:

There is an old East Indian proverb: "If you have an enemy give him an elephant; at first he will think you are his best friend".

The cowboy version of his anecdote is to give him an old horse......

The motorcyclist version is give him an old bike.



- Why you even want a bike:

http://www.cracked.com/article_19217_6-things-nobody-tells-you-about-owning-motorcycle.html



- The real costs of maintenance:

http://xjbikes.com/forums/index.php?threads/14581



- Before you buy:

www.clarity.net/~adam/buying-bike.html

Cyclechex vehicle history:
https://cyclechex.com

www.nicb.org/vincheck
The National Insurance Crime Bureau (NICB) is a useful site to check an un-titled bike, just to make sure it isn't stolen. You can always get a bonded title if the bike has no title.



- Proper Posture, Good Manners, Etc.: will a bike fit you?

http://cycle-ergo.com/



- The Previous Owner:

http://www.xjbikes.com/forums/threads/previous-owner-masterpieces.57929



- A Little Bit of Everything, great info (and insights) from down under:

https://www.youtube.com/playlist?list=PLwYMGfqlQ5KrfNvVQ1bJYXBurpaoMuTl2



- How to bring it home (import rules into the USA):

https://help.cbp.gov/app/answers/de...ments-for-importing-a-vehicle-/-vehicle-parts



- How not to trailer it:

http://www.eastpennwelding.com/things-we-cant-build/



- After you get it home:

http://xjbikes.com/forums/index.php?threads/33315

the checklist you've always wanted:

http://www.xjbikes.com/forums/threa...at-new-used-bike-home-help-appreciated.117398

the video guide you've always wanted (a Kawa ZL900, but same ideas apply):

https://www.youtube.com/watch?v=C76z0SHD7NU



- Before you start wrenching:

http://xjbikes.com/forums/index.php?threads/24010




- Tools You'll Need, And What You Need to Know About Them:

The best tool for removing problem fasteners?
Patience.

http://xjbikes.com/forums/index.php?threads/4168

and

http://xjbikes.com/forums/index.php?threads/4920

and

https://www.youtube.com/watch?v=pX4uHYEPOuY



- And What Fasteners You'll Want to Buy:

https://www.youtube.com/watch?v=pX4uHYEPOuY

https://www.youtube.com/watch?v=V1zuc6sNIrI

https://www.boltdepot.com/fastener-information/Printable-Tools/Type-Chart.pdf

http://www.oocities.org/dtmcbride/home_garden/fasteners.html



- Holy Exploded Views, Batman! The best tool you may ever have.....click on
any of his posts:

http://www.xjbikes.com/forums/index.php?members/flygp.8570/



- On the Road Again.......Enjoy The Ride......Road Trips:

http://xjbikes.com/forums/index.php?threads/20820

and

http://xjbikes.com/forums/index.php?threads/20458

and

http://xjbikes.com/forums/index.php?threads/33803



- And What to Pack on those trips:

http://xjbikes.com/forums/index.php?threads/33807

and

http://xjbikes.com/forums/index.php?threads/44284



- When I Must Put it Away For the Winter:

http://xjbikes.com/forums/index.php?threads/7065

By the way, the best fuel stabilizer to use, if you can easily find it, is race gas…..expensive, but it works:

http://www.motorcycleproject.com/text/gasoline.html



- Keeping up with the Joneses:

http://xjbikes.com/forums/index.php?threads/4769




- UP, UP, AND AWAY!:

Placing your bike on its centerstand is a procedure that quite a few new bike owners have a problem with; and these XJ bikes, being somewhat "front heavy", can make it a bit tougher to master this procedure. But once you get the hang of it (letting your foot do the work, rather than your arm or back), you, too, will be able to make instructional videos which make it seem effortless, too.

It's worth your time to learn how to do this properly (and effortlessly), as the use of the centerstand is a necessary "safety step" during many maintenance procedures, plus it makes you look really cool---instead of a wanna-b-biker---when you can perform this procedure without even thinking twice about it.....











BE PREPARED TO MEET YOUR MAKER:

The History of Yamaha:

http://www.xjbikes.com/forums/index.php?threads/tech-topic-the-history-of-yamaha.14576/




SAFETY ISSUES:


- BE THE BUNNY!:

a/k/a watch out for the caged wolves out there.......

http://xjbikes.com/forums/index.php?threads/11852

http://www.xjbikes.com/forums/threads/two-things-that-will-keep-you-alive.113686/



- DRESS FOR THE SLIDE, NOT FOR THE RIDE:

http://xjbikes.com/forums/index.php?threads/14524

and

http://xjbikes.com/forums/index.php?threads/29723

and

http://xjbikes.com/forums/index.php?threads/29675

and

http://xjbikes.com/forums/index.php?threads/32680

and

http://xjbikes.com/forums/index.php?threads/43691




- AVOID THE SLIDE, AND CONTROL YOUR RIDE:

U-turn:


Figure 8:


Avoiding hazards:
https://www.youtube.com/watch?v=6KgWPnO25_4

Target fixation:
https://www.youtube.com/watch?v=ewDS5ROrLcE

Decreasing radius turns and cornering:
https://www.youtube.com/watch?v=I1GDuD8JuWQ

Vanishing Points and cornering:
https://www.youtube.com/watch?v=5xtEI4vCAt4

 

ENGINE-RELATED ISSUES:


- THE SOUNDS OF SILENCE:

Stop, now, what’s that sound?
Everybody look what’s going down…….
- Buffalo Springfield

Yes, the joy of trying to describe a noise in text................and where it might be coming from.


* Don't quit yer' whining:

Yamaha used a straight cut primary gearset, which is very strong and a bit noisy. Typically heard as a whistle or a whine - some have compared it to a turbo sound. The RPM where it's audible will vary a bit from bike to bike, but it will make the noise in neutral and is pretty much not dependent on load.

GM also used straight-cut gears on some of their late 60’s muscle cars in the M22 “rockcrusher” 4-speeds. You can hear that same distinctive (some would call it almost musical…….) transmission whine even over the engine sounds in this video:



Of course, if you prefer your gear whine without bothering to use a clutch, try this:




* Whistling or chirping noises are some of the hardest to identify as to their source. Here's a couple of tricks:

Quick verification: take the plugs out. If the noise goes away then it's compression. If the noise remains, it's something else. "Something else" can be a number of things, but large vacuum leaks tend to give off whistling and/or chirping sounds...........


* Popping noise or what sounds like a bearing knock:

Possible it's a bad bearing, but more than likely it's a leaking exhaust gasket (hold a tissue around the exhaust joints and see if it flaps in the breeze.......)


* A bag-'o-marbles-in-a-tin-can sound:

This is typical of a starter clutch issue.....see the STARTER CLUTCH section below. Not a good thing........


* Clutch chattering:
http://xjbikes.com/forums/index.php?threads/38486

If the sound comes only when the clutch lever is squeezed, then check the throw out bearing. It's a radial needle bearing that is pulled by the rack and pinion inside the clutch cover, and when it goes bad it will squeal like a stuck pig.


* metallic sounds from the top end of the engine:

XJ550’s can make a particular type of “quiet” rhythmic, metallic knocking sound from the top end, which will disappear as rpm’s increase………..this is typically caused by a primary chain (inside the engine) which can “flop” around a bit at low rpm’s due to low oil pressure (oil pressure is used to tension this chain). It’s nothing to worry about.

A "tap-tap-tap" in the upper end may or may not be something to worry about; if it’s s “sharp” metallic sound…..that could be a cam bearing or cam cap problem. Both the XJ650 and air-cooled XJ750 engines had a factory TSB (Technical Service Bulletin, or in other words, an internal "warning" to their dealers) regarding slightly loose tolerances for camshaft end-play on these engines. It's a regular ticking sound that increases along with the engine speed, and is most easily heard from the right side of the head when the engine is hot. Generally, it is safe to ignore it, as no harm is being done. The camshaft end-play is not so large as to cause any damage.

If it’s just a soft, sewing-machine like tick-tick-tick sounds, then that is probably just the valves happily clicking away through their proper clearances. By the way, the lack of this tick-tick-tick sounds is not a good thing: tight valves make no sound, and tight valves are a quick way to ruin your engine!



- VALVE ADJUSTING SHIMS AND PADS:

The periodic checking and replacement of these valve clearance shims is one of the most over-looked of all the regularly scheduled maintenance tasks on these bikes.......and with predictably negative results.

The proper operating clearance of these shims (or, in the case of XJ700-X and XJ750-X engines, the Adjusting Pads) is necessary for both the maximum power output of your engine and the longevity of your camshaft and engine's life. Allow these clearances to get too small---which they will, over time---and you run the real risk of burning the valves (especially the exhaust valve) and that's just Not A Good Thing. An engine that runs poorly, stalls, or is very hard to start after it is fully warmed up, points to dangerously decreased valve clearances. Of course, if the shim clearances are too large, your engine will be down on compression and power throughout all rpm ranges.

And if the clearances vary from their specified ranges significantly in-between different cylinders, then it makes any attempt at engine synchronization---via the adjustment of the carb "synch screws"---meaningless and a sure way to reduce both the power output and the lifetime of your engine.



- IF YOU WERE A VALVE a/k/a VALVE SHIM ADJUSTMENT:

Think about what happens if YOU were a valve.......you get pushed around by the cam bucket/shim assembly, which gets pushed around by the CAM LOBE. The lobe is tapered so that it starts pushing at you at a certain point in the cam (engine) rotational cycle, and doesn't STOP pushing you around until much later in the rotation, at which time DUE TO SHIM CLEARANCE, you get a little break before the whole cycle starts anew.

Big bully, that cam lobe is…..

If there is little to no valve shim-to-cam-lobe clearance, then the cam lobe STARTS bullying onto you sooner, and ends its pushing LATER in each rotational cycle.....you (the valve) spend more time being lifted off your seat, due to the lack of clearance. Not only do you remain open longer during the compression stroke, you also don't get as much "face time" (ha-ha, a pun.....) with your valve seat, and that face time is when you get to cool down, and the lack of it really burns you up.......literally. You don't get to release your heat to the valve seat during that fully-closed time, and it's the equivalent of being cast into that ever-burning lake of fire and brimstone......

Not only that, but remember that there is a moment when both valves are open (called overlap" in camshaft-speak), and if the intake valve is OPENING SOONER, and the exhaust valve is CLOSING LATER (both due to being too tight, i.e. not enough clearance), then this overlap time (measured in degrees of cam rotation) is going to increase = lost compression.

And if that's not enough, the timing of valve opening and closure is what is known as cam timing, and tight valves will ADVANCE the cam timing (when the valve opening first begins in the rotational cycle), and this effects engine power in very real ways. While slightly advanced cam timing can increase engine performance, too much (or, even worse, a variable amount for each cylinder, based on differing clearances and thus different cam advance profiles for each cylinder!) makes a real mess of things. It's certainly not what the design engineers had in mind when they were tuning the engine for certain output at certain rpms......i.e. throttle responsiveness.

And finally, these engines are what are known as "interference" engines, meaning that within the cylinder, there are certain points in time when the piston and the valves occupy the same physical X, Y, Z coordinates within the cylinder (the piston at and around the TDC, the valve at and around full opening). At higher rpm's there is always going to be a little bit of valve "float", where the valve movement "lags" behind the cam lobe profile, in essence "floating" above the cam lobe profile for an instant or two, until the valve springs can overcome the momentum of the valve being rocketed off the top of the cam lobe profile. Although not an issue during the compression stroke, during the exhaust stroke if the valve is held open too long (lack of any shim clearance, or a "negative clearance" situation), the piston and valve may "interfere" with each other in decidedly unfriendly ways.

I keep referring to the LACK of shim clearance as being the major issue of concern, since that is the most common scenario......as time goes by, valve shim clearances are REDUCED due to the valve pounding its valve seat in the head (due to spring closing pressure banging the valve closed), thus forcing the seat further up into the head, thus bringing the valve stem/bucket/shim CLOSER to the cam lobe. This is the reason that periodic shim adjustment are needed, and, they are most needed on newer engines, as that is when the most valve seat recession occurs (first 10K miles or so). After that point, most of the valve seat compression is done, and valve clearances become more stable for longer amounts of time.

Of course, the opposite effects occur if shim-to-cam lobe clearances are too LARGE, the valve never opens fully, and it remains open for less time (the cam timing is retarded rather than advanced); you'll build full compression pressure, but won't be able to take advantage of it (not as much fuel entering, not enough time for exhaust gases to be pushed out). You won't be risking burning valves or having piston/valve interference issues, though.

Wow, just writing this out puts me into a cold sweat. I'm going to go check my clearances right now. A great photo journal of the valve clearance checking and replacement process for all air-cooled engines is documented at:

http://www.xjbikes.com/forums/threads/bigfitzs-airhead-valve-adjustment-with-pics.116006/

and

http://xjbikes.com/forums/index.php?threads/29209

and

http://www.xjbikes.com/forums/threads/valve-clearance-exhaust-side.94158/#post-522959

and




The procedures for the water-cooled "X-heads" can be seen at:

http://xjbikes.com/forums/index.php?threads/16298

and

http://xjbikes.com/forums/index.php?threads/29661

and here’s a useful tip:

http://www.xjbikes.com/forums/threads/odd-size-shims.68429/#post-468745



Oh, and another bit of advice to both the inexperienced and seasoned, as well----when it comes to remove the valve shims from their buckets, please block off the cam chain passage completely with a rag or paper towels in order to prevent a "popping shim" from migrating to a place that it doesn't belong (somewhere deep inside the bowels of your engine!):

http://xjbikes.com/forums/index.php?threads/17040


By the way, for those owners that use the molded rubber valve covers, you'll want to inspect and replace the "pressure washers" on the valve cover bolts, as those pressure washers are what actually create the pressure on the valve cover to seal the gasket. Here's the trick to making a frustrating job easier:

http://xjbikes.com/forums/index.php?threads/32854

and

http://xjbikes.com/forums/index.php?threads/40308


Finally, make sure that you set your clearances correctly; the Haynes manual has an incorrect listing for the XJ650 Seca models, don't let it fool you!:

http://xjbikes.com/forums/index.php?threads/33360



USEFUL TIP: sometimes you’ll come across an engine that has “zero-clearance” or negative-clearance valves…..an outrageous sign of previous owner(s) neglect (and, by the way, a real smoking-gun which shows that level of neglect probably applies to everything on such a bike, so you’d better double-check every critical system on such a bike twice!). Since there will be no “clearance” that can be measured, then there is no way to calculate what size shim(s) that you’ll need to get such valves back into spec, without first replacing the currently-installed shim with a much thinner shim (thin enough so that at least some amount of clearance begins to occur). If you can’t find an already-installed shim (on any of the other valves) that are small enough to obtain some amount of clearance on the offending cylinder(s), then we recommend that you order a variety of “very thin” shims from the list below, so you’ll have at least one size that will allow a clearance to be measured…..and then your correct size replacement can be calculated accurately. Based on experience, we would consider the 2.00mm - 2.20mm shims to be “very thin” for most engines




- ENGINE OILS and FILTERS:

Basic oil change procedure explained:

www.xjbikes.com/forums/index.php?threads/41046

and

www.xjbikes.com/forums/threads/oil-filter-assembly-install-detail.130464




When the filter housing bolt get stuck:

In case your filter housing bolt gets seized and frozen tight, here’s how to make it “take one for the team” and get it off:

http://www.xjbikes.com/forums/index.php?threads/im-back-and-my-f-in-oil-filter-is-stuck.55021



Of course, with our replacement spin-on filter kit, you’ll never have that problem again! Here are the instructions and installation:

http://www.xj4ever.com/spinon kit v2.1.pdf

http://xjbikes.com/forums/index.php?threads/23811

http://www.xjbikes.com/forums/index.php?threads/converting-to-a-spin-on-style-oil-filter.55881/



Which type and brand should you use? Great question! Here's some really good answers:

http://xjbikes.com/forums/threads/choosing-the-correct-oil-for-a-wet-clutch-motorcycle.43702

and

www.motorcycleproject.com/text/motoroil.html

and

www.motorcycleproject.com/text/motor_oil_more.html

and

www.motorcycleproject.com/text/motor_oil_mech.html


NOTE: Yamaha specifies the use of API "SE" or "SF" grade oil in all XJ models, but that is based on the original (at that time) automotive motor oil standards.....which, as the above article notes, are no longer valid in the current lubrication industry environment and classifications. Therefore we recommend that the oil you choose should meet or exceed the JASO "MA" duty rating, and all of the oils below exceed that standard. Do not EVER use synthetic oils unless they are specifically designed for motorcycle engines using wet clutch systems (as these bikes do use), as you will end up with a slipping clutches (both drive clutch and especially the starter clutch). Additionally, do not use "automotive" grade oils that have friction modifiers (reduced-friction additives) as these will cause the same problems.

The factory recommends the use of 10W30 oil when the outside temperature will never exceed 60-F, or 20W40 if the outside temperature is always above 40-F. Unfortunately, 20W40 oil is difficult to find anymore, but there is not an issue with using a straight 40W oil, or 10W40, 15W40, or 20W50 formulations instead.

All XJ-series engines require somewhere from 2.5 quarts to 3.0 quarts for an oil change (depending on whether the filter is replaced or not) except for the 1100 engines, which require slightly under a gallon to accomplish an oil and filter change.



- I see some metal shavings in my (oil pan, spark plug insulators, etc.). How do I tell what it’s from?

http://www.instructables.com/id/Identify-Metals/

KwonP1 :
This is a very basic guide, and really only applies to metals in its pure form. Most scrapyard and commercial sources have an alloyed form of each material, meaning its mixed with other metals and some of its properties will change. Often times it may be washed with another, electroplated, chemical plated, hardened, etc. Not unusual for something that appears to be one metal is actually another --- for example, gold and silver plated objects. Another example, pure tin may snap when bent, but the common 'tin sheet' is a steel sheet with a thin layer on tin on the surface, and it does not make noises when bent (e.g. with a metal brake).

A few of my own methods:

Aluminum: is diamagnetic: this means that aluminum will not stick to a stationary magnet, but a moving magnet will induce some magnetic properties. is that is reacts with vinegar (it starts bubbling) while aluminum doesn't, so this test makes it easier to distinguish between the two.

Chrome: is usually plated on to another metal, there is decorative that can tarnish, peel and flake off, if in good condition has a mirror finish, and is pretty soft. Then there is hard chrome often used on load bearing parts (axles, shafts, bearings, etc.) that is matte silver in color, can be very glossy in texture, will not be scratched even with a hardened steel sample, generally does not tarnish or corrode.

Magnesium: the best way to identify if something is solid magnesium is its price tag. Its expensive. really expensive. alternatively, small metal filings (shave off with a steel knife) will readily ignite by match or lighter flame and burn bright white. primary consumer uses would be performance engine blocks and performance car wheels (rims). In my metallurgy class we had a magnesium brake rotor from a commercial airliner laying around, and we knew about magnesium's self-reinforcing flammability once heated over its critical temperature. Needless to say, we shaved a few strips off of the rotor and took them and our oxy-acetylene torch to the lot outside the shop, and set light to it. The magnesium strips got red hot, and then combusted into an intense white flame. It left a small hole straight through the concrete and asphalt...so a word to the wise, be carefully with this stuff!!

Silver that turns black over time. the presence of ammonia in the vicinity of a metal can make it turn black. (learned this the hard way when i accidentally left steel tools in a bucket of water with some house paint in it) long term exposure to ammonia can cause pitting.

Titanium: is a tough one to identify, but again easy if you just look at the price tag, the stuff is priced more like gold! Titanium is rarely used in everyday objects, it’s found mainly in high-end products made for specialty, exotic purposes: medical, aeronautics, high end camping gear, jewelry, etc.



- DISSOLVE TO SOLVE THIS TRICKY PROBLEM:

Can you say intake manifold bolts and exhaust port studs? Shure you can……..





- STARTER CLUTCH:

"If there is not enough grip between the plunger and the roller, it can skip, causing the grinding, clacking noises you hear. I have been told by a Yamaha mechanic with over 20 years experience that it is very possible for some synthetics to greatly increase the chances that this will occur......

So this weekend I drained the synthetic out, put some cheap 20W50 in, and rode it for a little while. Then I drained the cheap oil out and put Castrol GTX 20W50 in and the starter does not malfunction anymore, not even once! I cant believe it! I guess these bikes were not made to run synthetic---I'm sticking with conventional oil from now on."


If the above solution doesn’t work, then it might be time to do the dirty deed. If you read this thread, you'll get a good idea of what challenges you're up against:

http://xjbikes.com/forums/index.php?threads/1700

When you finally get the starter clutch assembly out of the engine and available for rebuild, we suggest that the central hub unit be inspected carefully for any damage or cracks, and replaced if needed. Here is a common problem that you need to look for (scroll down for the image of the cracked hub):

http://xjbikes.com/forums/index.php?threads/18676


There’s only one way to repair a starter clutch that’s bad without splitting the engine cases, and it ain’t pretty:

http://xjbikes.com/forums/index.php?threads/48348


Luckily (?), you only need to remove the lower engine case to replace the clutch:

http://xjbikes.com/forums/threads/xj750-engine-removal-and-split-pictures.38545/


And here she is, the prize at the bottom of the Crackerjack Box:

http://www.xjbikes.com/forums/threads/complete-xj650-rebuild.81981/page-2#post-500076


ALSO, be aware that a failing battery and/or a starter motor with a shorted winding or excessive carbon build-up on the commutator, or even burnt contacts in the starter solenoid, can reduce current to the starter motor to a point where it can't produce enough torque upon the starter clutch, and thus mimic starter clutch failure symptoms (that "bag of rocks" sound and an engine that doesn't turn over), so be sure to eliminate those as potential problems before digging into your engine!

www.xjbikes.com/forums/threads/a-handy-guide-to-not-rebuilding-your-slipping-starter-clutch.130438




- ENGINE REBUILDING:


Rebuild Porn:

Engine removal and teardown:
www.youtube.com/watch?v=FcKAux55Pqc


Teardown continued:
https://www.youtube.com/watch?v=yTSGqSF68LE


Engine prep work:
https://www.youtube.com/watch?v=p4gl_1stuCs


More engine prep work:
https://www.youtube.com/watch?v=a5UVtnSbHig


Engine re-assembly:
www.youtube.com/watch?v=YnCTuwvB5sY


From Start to Finish:
http://xjbikes.com/forums/index.php?threads/38545




Valve Lapping Porn:

http://xjbikes.com/forums/index.php?threads/11820



Bent Valves Porn:

- or, why my engine has no compression on all 4 cylinders..........

http://xjbikes.com/forums/index.php?threads/42205



Just a quick heads-up:

- what I learned when swapping cylinder heads:

www.xjbikes.com/forums/threads/can-you-check-adjust-valves-with-the-head-off.112138/#post-565964



- those heat-treatment Crankshaft Blues:

http://www.xjbikes.com/forums/threads/starter-clutch-replacement.85364/page-4#post-509738



- getting kinda cranky:

http://www.xjbikes.com/forums/threads/primary-chain-yamaha-xj-900f.119007/

The large gear on the right is the primary drive gear.
The small sprocket in the center is for the cam chain.
The larger sprocket at left-center is for the alternator/starter clutch HYVO chain.

The oil pump is driven off of the clutch input shaft (the one that is driven by the primary drive).



SPLITTING UP IS HARD TO DO:

splitting the cases, and then actually putting it all back together again without any leftover parts:

http://xjbikes.com/forums/index.php?threads/38545


Re-sealing the cases isn’t hard to do, but you gotta be careful!

NOTE: you should review a service manual before applying this material to the engine cases, as there are certain areas (particularly around oil feed holes) that should never have sealer applied near them. See the bottom of page 2:

http://www.xjbikes.com/forums/threads/transmission-issue.59920/page-2#post-462239


A video tour inside your engine. Although this features an XS/XJ1100 engine, all of the basics are the same, and it gives a pretty good explanation of how the transmission part of the "engine" operates:





- ENGINE BEARINGS:

Crankshaft Bearings:

Yamaha used a unique way of "sizing" their engine bearings, both for the crankshaft main journal bearings and the connecting rod big-end bearings.

The factory coded, via a series of numbers indicating a "size code", numbers onto the crankcase, the crankshaft, and the connecting rods.

The crankCASE has numbers hand-scrawled onto the upper (and possibly the lower, also) engine case(s) ---typically, behind/below the stamped pad where the engine ID number is, behind the clutch cover opening, but, in reality, could be anywhere on the case(s) --- that specifies the main bearing saddle sizes for that particular engine case:

http://www.xjbikes.com/forums/threads/complete-xj650-rebuild.81981/page-2#post-498539

Note that these last 2 sets of 2 numbers --- “40’ / 46” and “45 / 40” in the above examples --- are the codes used for calculating the thickness of the shims used with the middle gear drive shaft of each particular engine.


The crankSHAFT will have two grouped sets of numbers on one end. The first set of 5 numbers are the main bearing journal size numbers for that crankshaft, and the second set of 4 numbers which denote the rod bearing journal numbers for that particular crankshaft. Both sets of numbers refer to the crank journals starting at the left side of the crankshaft (the #1 cylinder side, see the last picture in the post below):

http://www.xjbikes.com/forums/threads/complete-xj650-rebuild.81981/#post-498538


Each connecting rod also has a number that is stamped (with ink) on the rod itself, right where the upper and lower shells meet.


To calculate the correct bearing sizes to use in a particular engine, you will go through the following process:

Crankshaft Main Bearings:

The correct main bearing selection is made by subtracting the crankshaft journal number from the engine case main bearing saddle size number, for each main bearing journal position.


Connecting Rod Big-End Bearings:

The correct bearing selection is made by subtracting the crankshaft journal size number from the rod size number, for each rod/crank journal position.


For both the crank main journal bearings and the rod bearings, you will then use the numbers calculated above to realize a "bearing color" as outlined in the chart below. You would then order the correct "color" bearing for each crankshaft main journal or connecting rod big-end position:

Bearing "Color Codes":

#1 = Blue
#2 = Black
#3 = Brown
#4 = Green
#5 = Yellow

A good visual of the color marking on the bearing can be seen on page 11 at:

https://www.xj4ever.com/catalog/frame-engine-id.pdf



Example:

- Crankshaft is marked 21223 2111
- Engine case is marked 34534 48 47 (note that these last 2 sets of 2 numbers --- ’47’ and ‘48’ in this example --- are codes used for calculating the thickness of the shims used with the middle gear drive shaft)
- Rods are marked 6, 4, 3, and 3

The first set of 5 numbers on the crankshaft (21223) are the main bearing journal sizes for that crankshaft, and are sequentially #1 to #5 as read. The corresponding 5 numbers scratched onto the engine case (34534) are the main journal saddle sizes for that engine and are sequentially #5 to #1 as read. For the #1 main journal position (the far left position), we would have 4 (on the engine case) - 2 (on the crankshaft) = 2. The #1 main journal bearing is a "size" 2, which is a "black" bearing.

NOTE THAT THE HAND-SCRAWLED NUMBERS ON THE CRANKCASE READS JOURNALS #5 TO #1 as you read them left-to-right, and thus in a 5/4/3/2/1 sequence for the main journal bearing sizes! They are actually "backwards" from an intuitive approach (and "backwards" from the sequence they are coded onto the crank itself), but are "correct" in spatial orientation and sequence for the top crankcase half (since they are scrawled "reverse" in relation to the crankshaft position within the crankcase).


For the #1 con-rod, using the example above, you would use the 2nd set of numbers on the crankshaft (2111), and the ink-stamped number on the rod itself. So the #1 rod is stamped as 6, and the #1 crank rod journal is 2, and 6 - 2 = 4. Thus the #1 rod was use a "size" 4 connecting rod bearing, which is a "green" bearing.


Notice that it is NOT unusual for a single crankshaft to use a variety of different "size" or "color" bearings.


NOTE: The yellow "size" bearings are used only for crankshaft main journal bearings. Rod bearings were never made nor available in the yellow "size".

IN ALL CASES YOU SHOULD REFER TO A FACTORY SERVICE MANUAL OR A SKILLED, EXPERIENCED MACHINIST AS TO HOW AND WHAT SIZE ENGINE BEARINGS THAT NEED TO BE PURCHASED AND USED DURING AN ENGINE REBUILD! DO NOT PURCHASE ENGINE MAIN OR ROD BEARINGS BASED ON THE "NUMBERS" ALONE ---- YOU SHOULD ONLY PURCHASE YOUR ENGINE REBUILD PARTS AFTER ENGINE DIS-ASSEMBLY, PARTS MEASUREMENT, AND CONSULTATION WITH A MACHINIST.


Bearing Shell Thickness:

The only information that we're able to find is in a very few versions of various service manuals, and which gives the following specifications, but, we're not sure exactly what these measurements refer to (as it is not shown or explained what these measurements "mean", so we can only guess):

Blue: 1.5mm +0.002 to + 0.006mm
Black: 1.5mm +0.002 to - 0.002mm
Brown: 1.5mm -0.002 to - 0.006mm
Green: 1.5mm -0.006 to - 0.010mm
Yellow: 1.5mm -0.010 to - 0.014mm

The 1.5mm seems to be the nominal thickness of the bearing shell, but we're not quite sure what the +/- dimensions refer to. It might mean that, for example, that a "blue" bearing shell is anywhere from 1.502mm to 1.506mm thick, while a black shell is anywhere from 1.498mm to 1.502mm thick......maybe. Unfortunately this is guesswork on our part, and we cannot verify that (but, it does seem like the only logical conclusion). Yamaha (and to be honest, most of the Japanese engine manufacturers) use this somewhat odd method of bearing "sizing", quite unlike the standard western method of directly specifying certain bearing under/over sizes, i.e. 0.010, 0.020", etc. Of course, those methods also assume/allow for calculations based on any crank "grinding" that may be undertaken....a somewhat common option during engine rebuilding......whereas Yamaha does not recommend crank grinding: if the crank exceeds runout, or has defects (scratches, galling/burning, etc.), then Yamaha says to replace it.

Yamaha does specify that the main journal-to bearing oil clearance should be:
0.040 - 0.064mm (XJ550, *XJ650, and XJ750 air-cooled engines)
0.016 - 0.058mm (XJ700 air-cooled engines)
0.020 - 0.044mm (*XJ650, XJ700 water-cooled, XJ750 air-cooled, and XJ900 engines)
0.035 – 0.059mm (XJ1100 engines)

And the rod journal-to bearing oil clearance should be:
0.016 – 0.040mm (XJ750, XJ750 air-cooled, and XJ900 engines)
0.016 – 0.058mm (XJ700 air-cooled engines)
0.030 – 0.090mm (XJ550, XJ650 engines)
0.032 – 0.056mm (XJ700 water-cooled engines)
0.042 – 0.064mm (XJ1100 engines)

The maximum allowable runout for the crank main journals is specified at:
0.030mm (XJ550, all XJ700 engines, XJ750-X water-cooled, and XJ900 engines).
0.040mm (XJ650, all XJ750 air-cooled, and XJ1100 engines).

* different versions of the XJ650 engine manuals have differing values, for seemingly no particular reason at all. Additionally….in some manuals, the specifications give in the “specifications” sections of the manual differs from what is given in the same manual in pictorial representations of the crankshaft assembly, and/or what is specified in the “engine rebuilding” section of the same manual!

Executive Summary: Yamaha made a mess on the specifications surrounding engine bearing clearances, with information being present haphazardly, incorrectly in some places, and in a contradictory manner in other places. This seems rather odd for a company so proficient at the engineering tasks involved in building a durable, high-performance engine, but perhaps this is due to the issue noted above….that the Japanese engine manufacturers use a somewhat “odd” way of sizing bearings (although, in their defense, they probably had --- internally at least --- some very good reasons for doing it in such a manner).


This is why we always recommend using plastigauge to verify clearances.



Bearing Clearance Measurement:

As mentioned, bearing oil clearances are critical for engine longevity. Clearances are measured via the use of a thin, crushable plastic “bead” which is positioned between the bearing and the journal, and which is then crushed when the parts are torqued to proper specifications. The parts are then separated, and the width of the crushed plastic strips are compared against a (included) reference chart. This is a simple, accurante, yet very time-consuming task, but it must be done to insure that you engine assembly is done properly!

These measurements should be done for all bearing positions on the crankshaft main journals, the crankshaft rod journals, and all camshaft journals.




- [GRIN AND BEAR(ing) IT[/u]:

It’s estimated that 50+% of premature ball bearing failures are the result of improper installation. Given how hard they are to access, and how catastrophic the failure of internal engine shaft bearings can be, it’s especially important to follow the proper procedures for bearing replacement.

Here’s some good videos showing the proper method of installing ball bearings into engine cases and onto shafts:

https://www.youtube.com/watch?v=5dThHN7Rj6c

and

https://www.youtube.com/watch?v=wXZ-agyDsXY




- COMPRESSION TESTING:

Yamaha recommends that you perform a compression test every 5,000 miles or so, and that you should record the readings, per cylinder, for future comparison and evaluation. The acceptable readings (specified at sea level) are as follows:

To do a compression test properly, you should first make sure all of your engine valves are properly adjusted to their recommended clearances, as valves that are too "tight" (not enough clearance) will allow the intake or exhaust valve to be open more than is necessary, or at the wrong time within the compression stroke cycle, thus bleeding off compression that would otherwise be developed.

http://www.xjbikes.com/forums/threads/compression-test-xj650.113151

Do not use thread adapters or the like on your pressure gauge, as the added volume of air space within the adapter will reduce the indicated pressure readings.

a) make sure the engine is warm (at operating temperature).

b) remove all spark plugs, and then stick the plugs back into their caps and make sure the plugs are grounded to the cylinder head (or even better, disconnect your TCI unit).

c) remove the airbox filter lid and the air filter.

d) make sure the battery is FULLY charged, and remains so throughout the course of these tests! It is actually recommended that for purposes of compression testing that the TCI be un-plugged and jumper cables to a large capacity battery (i.e. car battery) be used to make sure that the cranking speed remains pretty constant between each reading. Slow or sluggish cranking speeds will reduce the indicated compression pressure. Yamaha specifies their compression pressures at 300 rpms (which is why the battery needs to be in good shape).

e) open the throttle FULLY and keep it open during testing.

f) crank the engine over until the needle stops advancing.

g) Let the starter cool down for a minute or so, then do the next cylinder, etc.).

h) If the readings are below spec, then shoot about a teaspoon amount of motor oil into each cylinder, crank the engine over a few revolutions with the starter (to spread the oil around), and then re-test each cylinder using the above procedure.

i) compare the two results and analyze.

j) keep all of your figures, and note the date and mileage from your odometer, so you can compare the next time you take readings (every 5,000 miles or so).


The specified compression pressures should be:

XJ550 engines:
Minimum: 100 psi
Standard: 121 psi
Maximum: 135 psi
Max. variance between lowest and highest: 14 psi


FJ600 engines:
Minimum: 142 psi
Standard: 156 psi
Maximum: 164 psi
Max. variance between lowest and highest: 14 psi


XJ600 Seca II engines:
Minimum: 145 psi
Standard: 160 psi
Maximum: 167 psi
Max. variance between lowest and highest: 14 psi


XJ650 and XJ750 air-cooled engines:
Minimum: 128 psi
Standard: 156 psi
Maximum: 171 psi
Max. variance between lowest and highest: 14 psi


XJ700 non-X (air-cooled) engines:
Minimum: 128 psi
Standard: 156 psi
Maximum: 171 psi
Max. variance between lowest and highest: 14 psi


XJ700-X and XJ750-X (water cooled) engines:
Minimum: 154 psi
Standard: 159 psi
Maximum: 165 psi
Max range allowable between highest and lowest readings: 14 psi


XJ900 engines:
Minimum: 114 psi
Standard: 142 psi
Maximum: 171 psi
Max. variance between lowest and highest: 14 psi


XJ1100 engines:
Minimum: 128 psi
Standard: 142 psi
Maximum: 156 psi
Max. variance between lowest and highest: 14 psi


NOTE: for readings taken at locations that are above sea level (ASL), the following correction factors should be applied to the readings that your gauge obtains:

- 500' ASL, multiply your readings by 1.013 to get a "true" compression reading.
- 1000' ASL, multiply your readings by 1.029 to get a "true" compression reading.
- 1500' ASL, multiply your readings by 1.042 to get a "true" compression reading.
- 2000' ASL, multiply your readings by 1.060 to get a "true" compression reading.
- 2500' ASL, multiply your readings by 1.072 to get a "true" compression reading.
- 3000' ASL, multiply your readings by 1.093 to get a "true" compression reading.
- 3500' ASL, multiply your readings by 1.103 to get a "true" compression reading.
- 4000' ASL, multiply your readings by 1.126 to get a "true" compression reading.
- 4500' ASL, multiply your readings by 1.136 to get a "true" compression reading.
- 5000' ASL, multiply your readings by 1.160 to get a "true" compression reading.
- 5500' ASL, multiply your readings by 1.172 to get a "true" compression reading.
- 6000' ASL, multiply your readings by 1.196 to get a "true" compression reading.
- 7000' ASL, multiply your readings by 1.233 to get a "true" compression reading.
- 8000' ASL, multiply your readings by 1.272 to get a "true" compression reading.


Also, be aware that barometric pressure differences (during testing events separated by more than just a few hours) will cause changes in indicated compression readings. Atmospheric pressure can vary significantly over time at the same altitude, due to weather systems….you hear this on weather reports, where the forecaster is talking about “High” and “Low” pressure systems. Basically, higher atmospheric pressures translate into higher indicated compression pressures. Although it is rarely of major consequence, in order to be "dead-nuts" accurate you should also record your local barometric pressure at the time of each test. If you measured compression on a day when it was 1030mbar and observed 150psi, and then took a measurement later in the week/month/etc. when the ambient air pressure was only 990mbar, that’s an environmental air pressure difference of about 4%, and assuming nothing else had changed you would then read a 4% less compression pressure of only 144psi......


But don’t overlook the fact that the individual test gauge being used is probably the greatest variable. Some compression gauges are just not very accurate to begin with (basically, and within reason --- and just like with most tools --- the it costs the more accurate it will tend to be). Also, try to keep the hose on the gauge you are using as short as possible….the space inside the hose adds to the volume of the cylinder, as lowers the compression ratio a bit, and thus reduces compression pressures.

And in case you are interested, here are the standard compression ratios for the various engines:

XJ550: 9.5-to-1
FJ600: 10.0-to-1
XJ600 Seca II: 10.0-to-1
XJ650 (except Turbo): 9.2-to-1
XJ650 Turbo: 8.2-to-1
XJ700 air-cooled: 9.5-t-1
XJ700-X and XJ750-X water: 11.2-to-1
XJ750 air: 9.2-to-1
XJ900: 9.6-to-1
XJ1100: 9.0-to-1
XS1100 9.2-to-1

Note that the XJ650 Turbo engine has a much lower static CR than all other engines……logically so, since it has a device (the turbocharger!) that raises the atmospheric pressure of the incoming air charge. Also of note is the rather “sky-high” CR of the multi-valve Genesis engines in the water-cooled “X” engines, which is also one of the keys to their vastly increased power output.



Now Analyze This!:

1) If one or all of your cylinders are too low in pressure, it means that:

a) you did the compression test incorrectly

b) the tester gauge is inaccurate, or was not used properly.

c) your engine has piston ring, piston wall, or valve leakage problems.

d) your valve clearances are too tight, and should be adjusted, or aftermarket camshafts have been fitted that have altered the camshaft timing.

e) if a cylinder or cylinders have NO compression at all, that typically means your piston has been catastrophically damaged (i.e. a hole in the piston crown, broken piston, etc.)

f) if a cylinder or cylinders have good compression that rapidly "leaks away" (best determined by the use of a Leakdown Tester gauge as listed further below), this points to burned or otherwise problematic valves.

In order to further analyze a low-compression condition, you should squirt a small amount of engine oil into the suspect cylinders (about a teaspoon), crank the engine over for a few revolutions to spread the oil about, and then re-test those cylinders.

g) if the compression pressures RISE by a large amount after the infusion of oil, then this typically means that the pistons, piston rings, or cylinder walls are damaged or worn in some way(s). However, be aware that if you introduced a significant amount of oil into a cylinder (1 teaspoon or more) when conducting this test, a small rise in pressure may occur, and it may instead mean that your valves are the problem, since the introduction of that much oil in a small cylinder will naturally cause the compression to rise.

h) if the compression pressures do NOT rise after the infusion of oil, then this typically means that the valve seats or faces are worn, or a valve is hanging up within its guide, or your valve clearances are way too small.

i) if two adjacent cylinders (cylinders 1 and 2, or cylinders 3 and 4) have low compression, and the oil treatment produces no greater pressures, this points to a damaged cylinder head gasket, warped head, etc.

j) it can be very useful to introduce 20-30 psi of compressed air into the cylinder (thru the spark plug hole) to help identify the source of low compression: the escaping air can pinpoint the source of the leak (air hissing out of the intakes or exhaust points to valve problems, while air escaping thru the crankcase breather indicates ring-seal issues).


Of course, many other situation may cause low cylinder compression, including valves that are out of adjustment (too tight, thus holding a valve slightly open all the time, losing compression), cracked pistons, cylinders, or cylinder heads, but those situations are the not all that common.



2) If one or all of your cylinders are too HIGH in pressure, it means that:

a) you piston domes (tops) and/or the cylinder head combustion chamber have a significant accumulation of carbon upon them, which should be cleaned via some type of chemical treatment or engine dis-assembly and manual removal methods. Note that higher cylinder pressures caused by such build-up may be "masking" or hiding other problems that might cause LOW cylinder pressures, such as worn rings, etc.

b) your engine has been fitted with aftermarket, high-compression pistons, or has had the cylinder head "shaved".

NOTE: high cylinder pressures are NOT a good thing, as they tend to blow out head gaskets and can cause accelerated piston, piston ring, or bearing wear.


You can also test for piston ring and cylinder wall condition by performing a "leak-down" test, which consists of forcing a measured amount of compressed air into a cylinder, and then seeing how long before this air "leaks" out of the combustion chamber and down into the crankcase (past the ring seal):

http://www.dietersmotorsports.com/Compression-leakdowntest.htm


NOTE: be aware that some of the ultra low-priced gauges that are typically advertised on eBay, etc. can be quite un-reliable in their readings, and may regularly indicate a false (low) compression reading.



- PISTONS, PISTON RINGS, AND RELATED:

Pistons and piston rings are not ordered until AFTER engine teardown and cylinder wall diameter, taper, and other critical measurements and conditions are inspected, and the determination is made concerning what the final cylinder size is needed (standard bore, 1st oversize, etc.).

Only then does the purchase of the appropriate sized pistons and/or ring sets commence. Pistons are then measured for their actual size (as opposed to their "supposed-to-be" advertised size), and only then does engine boring occur, to allow for and result in the proper piston-to-cylinder clearances. Piston rings are then fitted and sized to the actual finished cylinder dimensions before installation.

ANY MACHINIST OR SHOP THAT DESCRIBES TO YOU A PROCESS OTHER THAN THE ABOVE, PLEASE TAKE YOUR ENGINE AND BUSINESS ELSEWHERE, as they are planning on "cutting corners" on your engine rebuild and such actions will cost you dearly in the performance and longevity of your rebuilt engine.


- All original and aftermarket piston rings are "directional"....the top and second ring are designed to be installed in a certain orientation. Check your service manual for the proper installation procedures. Most factory oversize rings have their oversize dimension stamped into the top ("up") surface of the ring; standard sized rings typically do not have any such markings. 2nd (center) rings are always installed with their wider, "scraper" edge towards the bottom of the piston:

UP
___
|____\

DOWN

- All original and aftermarket piston rings must be sized to the finished bore dimensions by filing the end gap to achieve proper specified clearance (end gap). Failure to do so can result in seized rings. Most air-cooled engines run "choked" cylinders.....the cylinder bore is smaller at the bottom of the bore and larger on top (after the cylinder reaches operating temps, the bore stabilizes). This "choke" is also known as bore taper and is critical.

When measuring your cylinder, take your readings with a t-gauge or cylinder bore dial indicator at the BOTTOM of the choke. This will give you your tightest ring gap reading. Once you determine which rings to buy, you'll need to hand-check each one by pushing it to the bottom of the choke to measure your ring gap. If it's too tight, you'll need to file the ends of the gap to open up the clearance. This can be done hand with a small flat file, but it's a much wiser idea to buy a ring gap filer------it does a much neater and far more accurate job. It is also recommended that a proper size Flex Hone be run down the bore PRIOR to fitting the rings......the cross-hatch finish that the flex hone creates will give new rings a nice bore pattern with which to seat.

- a good tutorial on piston ring break-in procedures can be found here:

http://www.ntnoa.org/enginebreakin.htm


If you want to de-carbon your piston crowns, valves, or combustion chambers, then a 50/50 mix of automatic tranny fluid and acetone (careful, extremely flammable!) left overnight on the carboned areas will help to soften and loosen the carbon, allowing easier removal with a brass brush.


By the way, here's the main reason you don't want to run lean over an extended period of time:

http://www.xjbikes.com/forums/threads/head-gasket-1982-maxim-650.85273/#post-504365

A holed piston. Notice how it's right where the plug fires (the hottest point anyway, and made ultra-hotter by a lean fuel condition).



And all the inside dope on cast versus forged piston is nicely summarized right here:

http://www.motorcycleproject.com/text/cows-pistons.html

and

http://www.motorcycleproject.com/text/cows-offset.html



- GASKETS and SEALS:

- A great pictorial guide to replacing the tach cable drive o-ring and seal can be seen at:

http://www.xjbikes.com/forums/threads/another-tach-gear-housing-oil-seal-replacement.118797


- and here's a good write-up on changing the alternator shaft oil seal on a later model Yamaha (XJ600 Seca II).....although the procedure is not exactly the same on the 1980's XJ-series engines, it's close enough to show the entire process, and with very good pictures:

http://www.xjrider.com/viewtopic.php?t=2101

And here is the procedure shown on an XJ700 engine, other XJ engines of this era are very similar in procedure:

http://www.xjbikes.com/forums/threads/replacing-alternator-seals-in-xj700n-with-pictures.108126


NOTE: in some situations, you can use the following technique to remove larger oil seals that would otherwise require case-splitting to remove. All large oil seals have a metal inner structure that you can (very carefully!) drill into and then pry out:

http://www.xjbikes.com/forums/threads/replacing-the-output-shaft-seal.110522/



- CAMSHAFT TIMING:

a/k/a preventing a good-night “kiss” between your valves and piston crowns….

Make absolutely sure that your cams and chain are clocked correctly to your crank, or your motor might easily become toast. Although there is no substitute for having a factory or aftermarket service manual in performing this procedure, here are the basic ideas involved:

http://www.xjbikes.com/forums/index.php?threads/48419

http://www.xjbikes.com/forums/threads/valve-timing-dots.87999/


NOTE: in the truest hot-rod tradition, people sometimes inquire as to camshaft specifications and interchange. We have compiled the following information for your reading pleasure:

XJ550 Maxim:

Intake Lift: 6.80mm
Exhaust Lift: 6.80mm

Duration: not given

Overlap: not given


XJ550 Seca:

Intake Lift: 7.80mm
Exhaust Lift: 7.10mm

Duration: not given

Overlap: not given


XJ650 all models except Turbo:

Intake Lift: 8.50mm
Exhaust Lift: 7.80mm

Duration:
Intake opens 34-degrees BTDC
Intake closes 58-degrees ABDC

Exhaust opens 66-degrees BBDC
Exhaust closes 26-degrees ATDC

Overlap: 60-degrees


XJ650 Turbo:

Intake Lift: 8.50mm
Exhaust Lift: 7.80mm

Duration:
Intake opens 28-degrees BTDC
Intake closes 48-degrees ABDC

Exhaust opens 53-degrees BBDC
Exhaust closes 23-degrees ATDC

Overlap: 51-degrees


XJ700 non-X models:

Intake Lift: 8.80mm
Exhaust Lift: 8.30mm

Duration: not given

Overlap: not given


XJ700-X and XJ750-X models:

Intake Lift: 7.50 - 7.70mm
Exhaust Lift: 7.35 - 7.55mm

Duration: not given

Overlap: not given


1981-83 XJ750 models:

Intake Lift: 8.80mm
Exhaust Lift: 7.80mm

Duration: not given

Overlap: not given


XJ750RL models:

Intake Lift: 8.80mm
Exhaust Lift: 8.30mm

Duration:
Intake opens 38-degrees BTDC
Intake closes 58-degrees ABDC

Exhaust opens 56-degrees BBDC
Exhaust closes 26-degrees ATDC

Overlap: 74-degrees


XJ900RK and RL models:

Intake Lift: 8.75mm
Exhaust Lift: 8.25mm

Duration:
Intake opens 38-degrees BTDC
Intake closes 58-degrees ABDC

Exhaust opens 66-degrees BBDC
Exhaust closes 26-degrees ATDC

Overlap: 64-degrees


XJ1100 and XS1100 models:

Intake Lift: 8.80mm
Exhaust Lift: 8.80mm

Duration: not given

Overlap: not given



SOME TANTALIZING THOUGHTS: although we have not----and do not know of anyone who has---there may be opportunities for performance gains via cam-swapping between different models. Here is what we can say with surety:

a) XJ550 Maxim and Seca cams can be swapped between these engines (but not with any of the 650-up engines). The 550 Seca cams are "hotter", they have more lift, and probably also have increased duration and possibly overlap.


b) all XJ650 (except, perhaps, for the Turbo models), XJ700 non-X, and XJ750 model cams will interchange. Here's the lift variances between them:

Intake:

* 650 models (except Turbo): 8.50mm
* 700 non-X models: 8.80mm
* 1981-83 750 models: 8.80mm
* 1984 XJ750RL models: 8.80mm

Exhaust:

* 650 models (except Turbo): 7.80mm
* 700 non-X models: 8.30mm
* 1981-83 750 models: 7.80mm
* 1984 XJ750RL models: 8.30mm


Since the cam lift durations and overlap specifications are not available for all models, we can only (for now) guess what those differences are; however, it would be reasonable to speculate that the 700 non-X and XJ750RL cams are the "hottest" of the bunch, followed by the 1981-83 750 cams, and lowest on the totem pole would be the 650 non-Turbo cams.

Although camshaft design and swapping is a real black art, as not only are lift, durations, and overlap issues involved, there's also cam-timing considerations as well as the interaction between all those factors and cylinder size, air flow into and out of the cylinders, etc. to account for.

Please note that in order to correct (or enhance) other design parameters or issues, it is sometimes best to swap out ONLY the intake OR the exhaust cam (rather than both)......so much depends on the engine and bike in question, the intended usage, rpm power range desired, etc.

Like we said, a black art....... Remember, "hotness" in camshafts, just like beauty, is in the eye of the beholder, and it depends on whether your definition of "hot" is "low-end power", "all-around power", "high-end screamer", or some other variation of the above.

If anyone has any experience with cam swaps on these engines, please let us know what you did, and how it worked out!!


c) XJ700-X and XJ750-X cams do not interchange with any other XJ-series engines.

The Yamaha Genesis engines, not just another purdy face:

http://www.motorcycleproject.com/text/cows-multi.html


d) XJ900RK and RL cams----these we just don't know about. We BELIEVE (but cannot assure you) that they will interchange with all XJ650, XJ700 non-X, and XJ750 engines. If so, they are probably the "hottest" cams available.


e) XJ1100/XS1100 cams do not interchange with any other XJ-series engines.



- CAM CHAIN TENSIONERS:

The secret life of cam chain tensioners can be explored further at:

http://xjbikes.com/forums/index.php?threads/24597

and

http://xjbikes.com/forums/index.php?threads/28447


Yamaha specifies that for the manual-tensioner models, the adjustment should be checked and adjusted (if necessary) every 5,000 miles. Automatic tensioners should never need checking, as they should adjust themselves, well, automatically!

Here's some tips on how to go about doing this adjustment properly:

http://xjbikes.com/forums/index.php?threads/23008




- YIKES!: ALL ABOUT THE "YICS" SYSTEM!:

http://xjbikes.com/forums/index.php?threads/yikes-all-about-the-yics-system.14757/




- ENGINE SWAPS:

A brief musical interlude here, folks. Since this question comes up fairly often, we'd like to offer the following pointers when considering or performing an engine swap into your bike:

XJ550 models:

Being a chain-driven bike (unlike all the 650cc-up models, which are shaft-driven), swapping the larger engines into the XJ550 frames is basically a Job for Jesus, or those with similar amounts of time and talents (and, lots of fabrication money, too!). There's simply no easy way to get from "here" to "there".

The most likely donor engine would be from a FJ600 or similar model.


XJ650 models:

Since one of the most popular engine swaps is putting an XJ750 engine into an XJ650 frame, we offer the following tips and guidelines regarding what issues you might expect to have to deal with in regards to this popular conversion. Also note that XJ750 Maxim/Midnight Maxim engines mount differently than XJ750 Seca engines, due to the lack of the rubber engine mounting insulators on XJ750 Seca crankcases.

* when putting an XJ700 (air-cooled) engine into a XJ650 Maxim, Midnight Maxim, or RJ Seca frame, please observe the following changes:

- observe the same procedures and cautions as applies to using the XJ750 Maxim/Midnight Maxim engines. The air-cooled XJ700 engines use rubber insulators to mount them to the frame, but you will need to retain the XJ650 engine mounting hardware (XJ700 engine mounts are in a different relative position in the frame).
- it is unknown which airbox boots you will need to use.
- the XJ650 Maxim/Midnight Maxim use the same style shifter assembly as an XJ700 engine, but differ from the XJ650RJ Seca shifter assembly.
- have to convert tachometer to an electrically driven version on all 1980-81 XJ650 Maxim, Midnight Maxim, and 1982 XJ650RJ Seca models.
- the XJ700 oil level sender can be used.
- will need to use XJ700 carbs and intake manifolds.
- need to retain XJ650 exhaust system.
- need to retain XJ650 wiring harness, except for the pick-up coils sub-harness. The pick-up coils on the XJ700 engines are different. Need to use the XJ700 TCI box.
- when using an XJ700 engine, be aware that there is a slight gearing difference----the XJ700 models have a slightly different gear ratio, also, even though they share the same size rear wheel as the Maxim. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.
* it would be advisable to use the XJ700 swingarm assembly and driveshaft.
* one note of interest: the XJ700 engines, although of the same basic design as the XJ650 and XJ750 engines, are actually a much more "heavy-duty" unit, employing some of the XJ650 Turbo and XJ900 internal engine refinements and upgrades, as well as using a stronger, 6-spring clutch system, and also a much larger and stronger u-joint and driveshaft.


* when putting an XJ700-X or XJ750-X (water-cooled) engine into a XJ650RJ Seca frame, please observe the following changes:

http://www.xjbikes.com/forums/threa...-put-an-x-engine-into-a-650-seca-frame.42248/

and

http://www.xjbikes.com/forums/threads/highly-modded-650-seca.85760/


* when putting an XJ750 engine into a 1980-81 XJ650 Maxim or Midnight Maxim frame, please observe the following changes:

- have to convert tachometer to an electrically driven version.
- the original XJ650 oil level sender needs to be retained (unless the engine is from a 1983 750 Maxim or Midnight Maxim).
- the 650 shifter side cover and all internal components needs to be retained, unless you want to keep the 750 Seca style shifter. The 750 Maxim style shifter may not work.
- the engine mounting hardware for the XJ750 engine will need to be used (no rubbers on XJ750 Seca; XJ750 Maxim used the same basic hardware. Use the XJ650 front upper frame brackets when using a Maxim engine; the XJ750 Seca frame brackets when using a Seca engine).
- will need to use XJ650 airbox boots.
- will need to use XJ750 carbs (or re-establish the XJ650 carbs to XJ750 specs).
- need to retain XJ650 exhaust system.
- need to retain XJ650 wiring harness, except for the pick-up coils sub-harness. The pick-up coils on the XJ750 engines are different. Need to use the XJ750 TCI box.
- when using an XJ750 engine, be aware that there is a slight gearing difference----the XJ750 Seca used a 18" rear wheel, while the XJ650 Maxim models used only a 16" rear wheel, and thus middle drive gear ratios are slightly different inside the tranny. The XJ750 Maxim models have a slightly different gear ratio, also, even though they share the same size rear wheel as the Maxim. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.


* when putting an XJ750 engine into a 1982-83 650 Maxim frame, please observe the following changes:

- the original XJ650 oil level sender needs to be retained (unless the engine is from a 1983 750 Maxim or Midnight Maxim).
- the 650 shifter side cover and all internal components needs to be retained, unless you want to keep the 750 Seca style shifter. The 750 Maxim style shifter may not work.
- the engine mounting hardware for the XJ750 engine will need to be used (no rubbers on XJ750 Seca; XJ750 Maxim used the same basic hardware. Use the XJ650 front upper frame brackets when using a Maxim engine; the XJ750 Seca frame brackets when using a Seca engine).
- will need to use XJ650 airbox boots.
- will need to use XJ750 carbs (or re-establish the XJ650 carbs to XJ750 specs).
- need to retain XJ650 exhaust system.
- need to retain XJ650 wiring harness.
- when using an XJ750 engine, be aware that there is a slight gearing difference----the XJ750 Seca used a 18" rear wheel, while the XJ650 Maxim models used only a 16" rear wheel, and thus middle drive gear ratios are slightly different inside the tranny. The XJ750 Maxim models have a slightly different gear ratio, also, even though they share the same size rear wheel as the Maxim. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.


* when putting an XJ750 engine into a 1982 650RJ Seca frame, please observe the following changes:

- have to convert tachometer to an electrically driven version.
- the original XJ650RJ oil level sender needs to be retained (unless the engine is from a 1983 750 Maxim or Midnight Maxim)
- the 650RJ shifter side cover and all internal components are the same as those in a XJ750 Seca engine. The 750 Maxim style shifter may not work.
- all engine mounting hardware for the XJ750 Maxim engine will need to be used (no rubbers on Seca engines; an XJ750 Seca engine uses the same mounting hardware as the XJ650RJ Seca, except for the front upper frame brackets, the XJ650RJ Seca frame brackets should be used. If using an XJ750 Maxim engine, you'll need to be creative.............
- will need to use the XJ650 airbox boots.
- will need to use XJ750 carbs (or re-establish the XJ650 carbs to XJ750 specs).
- need to retain the XJ650RJ exhaust system
- need to retain the XJ650RJ wiring harness, except for the pick-up coils sub-harness. The pick-up coils on the XJ750 engines are different. Need to use the 750 TCI box.
- when using an XJ750 engine, be aware that there is a slight gearing difference----while both the XJ650RJ Seca and the XJ750 Seca models used a 18" rear wheel, the XJ750 Maxim models used only a 16" rear wheel, and thus the middle drive gear ratios are slightly different inside the tranny on some engines. Thus there will be a difference in the acceleration of the bike, depending on which donor engine is used.


* when putting an XJ900 engine into a XJ650 Maxim, Midnight Maxim, or RJ Seca frame, please observe the following changes:

- it can be done: http://xjbikes.com/Forums/viewtopic/t=29398.html

The same guidelines as generally outlined in the XJ700 engine swap should be observed.


* when putting an XJ1100 engine into a XJ650 Maxim, Midnight Maxim, or RJ Seca frame, please observe the following changes:

- put down the tools and the torch and back s-l-o-w-l-y away from the bike.
- 1100 engines are vastly different than the other XJ650/700/750/900 engines in design, style, size, etc., and attempting to put one of these engines into the smaller frames is likely to be a complete custom job. No other information is available. It would be wise to consider buying an XJ1100 model bike, and riding that, rather than trying to transplant just the engine.....


XJ700 air-cooled models:

Most of the engine-swap modifications in regards to the XJ650 engines above will apply, and recall that the XJ700 engines are rubber-mounted. However, due to the unique frame style and engine mounting positioning, you will need to use the XJ700 frame mounting brackets and hardware.

Please note that we have not attempted such a swap, and welcome further experience from those who have completed such as transplant for any additional insights.


XJ700 or XJ750 water-cooled models:

Although it should be possible to put an XJ-series air-cooled engine into the water-cooled frame, there will be many significant engineering challenges involved, as the XJ700-X and XJ750-X frames are unique enough that many difficulties will present themselves.


1981-83 XJ750 air-cooled models:

Most of the same consideration would apply as outlined in the XJ650 Section, just reversed. With the exception of the engine-mounting issues (rubber mounts on Maxim models, solid mounts on Seca models), all XJ750 air-cooled engines are basically identical to each other.


XJ750RL and XJ900 models:

No information is available on using the smaller XJ650/700/750 engines in the XJ750RL or 900 frame, although theoretically it should work.

Of course, XJ550 and XJ1100 engines will not fit into the XJ750RL or XJ900 frames without extensive efforts and modifications.


XJ1100 models:

Much like the XJ550 models, these engines are rather unique in a verity of ways, and thus preclude swaps with their smaller XJ-cousin engines. XS1100 engines should work, but this is not an area in which we have any definitive experience.



Unfortunately, we have no good advice if this is your goal!:

http://xjbikes.com/forums/index.php?threads/29649[/b]

 

BRAKE SYSTEMS:

- FRONT BRAKE LINES SAFETY ALERT!:

http://xjbikes.com/forums/index.php?threads/41400



- FRONT BRAKE SYSTEM SAFETY ALERT!:

http://xjbikes.com/forums/index.php?threads/41403

and





- REAR DRUM BRAKES SAFETY ALERT!:

http://xjbikes.com/forums/index.php?threads/15874

and the how-to guide for replacing the rear brake shoes:

http://www.xj4ever.com/rear drum brakes.pdf

and






- FRONT BRAKE SYSTEM UPGRADE:

Lookin' good and stopping power:

http://xjbikes.com/forums/index.php?threads/16019



- BRAKE LINE INSTALLATION:

http://www.xj4ever.com/ss brake line install.pdf



- BRAKE PEDAL INSTALLATION:

NOTE: the rear brake pedal and it's mating splined pivot shaft have alignment marks cast in (the pedal) and punched into (the end of the pivot shaft) to allow you to set the installed pedal height to the factory-recommended position:

http://www.xjbikes.com/forums/threads/help-what-are-these-bolts.82812/#post-499455



- FRONT SINGLE-TO-DUAL DISC BRAKE CONVERSION:

Thinking of converting a single front disc (XJ550's, XJ650 Maxim or Midnight Maxim) bike to dual front discs? It takes more than you first might imagine.....since you'll need to have the forks necessary to accept the extra caliper that is needed........and that is where the fun begins! For the XJ550 Maxim and XJ650 Maxim and Midnight Maxim models, it is usually simpler to swap out an entire front end from a XJ750 Maxim model to do a proper conversion:

XJ550 Seca upgrade to dual discs:

http://xjbikes.com/forums/index.php?threads/14588


XJ550 Maxim and XJ650 Maxim/Midnight Maxim upgrade to dual discs:

http://xjbikes.com/forums/index.php?threads/14368



- REAR DRUM-TO-DISC BRAKE CONVERSION:

A lot of effort for a cool look, but don't expect that much additional stopping power (front brakes do 80% of the braking, and you really don't want to be locking up the rear wheel during panic stops!.......

http://xjbikes.com/forums/index.php?threads/15759




- CALIPER REBUILDING:

But, one thing that the service manuals don't mention is that after all these years of abuse (and probably neglect), that the recessed fluid and dust seal ring lands in the caliper body have probably accumulated an awful lot of built-up rubber gunk and what-not, and unless you get those ring lands zestfully clean and completely free of all of the built-up junk, your new piston seals will not seat properly and will not seal properly (or, will cause the piston to jam within the bore as it is pushed "sideways" by the bulging, uneven rubber seals)....please review the pictures and procedures on the 2nd page:

http://xjbikes.com/forums/index.php?threads/12529


A special how-to on removing frozen brake caliper pistons on dual-piston models (FJ600, XJ700, XJ750-X, XJ750RL, and XJ900 models):

http://xjbikes.com/forums/index.php?threads/40059

and the rebuilding of these style dual-piston calipers:

https://www.xjbikes.com/forums/threads/1985-86-xj700-caliper-rebuild.118121




- MASTER CYLINDER REBUILDING:

Identification:

NOTE: before ordering your master cylinder rebuild parts, please take a moment to inspect and confirm that your bike does indeed have a factory original (for your model) master cylinder on it. After all these years….and so many previous owners…...there’s no telling what’s resting up there on your handlebars, and since rebuild parts are quite specific designed to work only with a particular style master cylinder ----- well, it’s best to be safe than sorry!

So here are the clues for original master cylinder identification:

XJ550 all North American models: the cylinder body will have the size 1/2 and the word NISSIN cast into it along the larger rear facing side of the cylinder body. Original (1981-83) cylinders will have the word NISSIN in all capital, block-style letters, while later “replacement” cylinders will have the word NISSIN appear as a stylized semi-script, with the two “s” letters layered on top of each other. Both types will accept all of the parts that we have listed below as fitting original master cylinders.

XJ550 non-North American models (dual-disc bikes): the cylinder body will have the word NISSIN cast into it along the larger rear facing side of the cylinder body, and have the size 5/8 cast into the forward face of the cylinder body just to the left of the fluid outlet port (where the brake line attaches).

FJ600 and XJ900 F, N, and FN models: the cylinder body will have the size 5/8 cast into large front face side of the cylinder body just above the fluid outlet port (where the brake line attaches), and the manufacturer name does not appear anywhere on the cylinder body.

XJ600 Seca II models: the cylinder body will have the size 14 (meaning a 14mm bore) cast into large front face side of the cylinder body, and the manufacturer name does not appear anywhere on the cylinder body.

XJ650 Maxim and Midnight Maxim North American models (single-disc): the cylinder body will have the size 14 (meaning a 14mm bore) and the word NISSIN cast into it along the rear face of the piston bore.

XJ650 non-North American (dual disc) models, XJ650RJ Seca, all XJ700, XJ750-X, XJ750RL, and XJ900RK and RL models: the cylinder body will have the word NISSIN cast into it along the larger rear facing side of the cylinder body, and have the size 5/8 cast into the forward face of the cylinder body just to the left of the fluid outlet port (where the brake line attaches).

XJ650 Turbo, 1982-83 XJ750 Maxim and Midnight Maxim, and all XJ750 Police models: the cylinder body will have the size 5/8 cast into it along the larger rear facing side of the cylinder body, and the word NISSIN does not appear anywhere on the cylinder body. The 1982 XJ750 Maxim cylinders have a small (1/4” diameter) hole in the base of the reservoir where the fluid level sensor wires exit the inside of the reservoir.

XJ750 Seca and all XJ750 Euro models: ]: the long skinny cylinder body will have the size 11/16 (meaning a 17.5mm bore) cast into it along on side the piston bore, and the word NISSIN does not appear anywhere on the cylinder body. A good image of this type cylinder can be seen at: http://www.xjbikes.com/forums/threads/new-member-need-help-with-brakes.78654/#post-492845

XJ1100 Maxim and Midnight Maxim models: the cylinder body will have the size 14 (meaning a 14mm bore) cast into it along the rear face of the piston bore, and the word NISSIN does not appear anywhere on the cylinder body. The bottom of the reservoir has a small (1/4” diameter) hole in where the fluid level sensor wires exit the inside of the reservoir.


If your master cylinder does not match the above descriptions, then we may not be able to assist you with rebuild parts for it…..there are an incredible number of both original and aftermarket master cylinders that were/are available, they all look somewhat the same, and they all may or may not accept nor function properly (or at all!) with component intended for use with the original master cylinder used on your bike!



A pictorial overview of the master cylinder rebuild process can be observed at:

http://xjbikes.com/forums/index.php?threads/18377

and

http://www.venturerider.org/forum/showthread.php?116337-Clutch-Hydraulic-Rebuild-Tutorial

and

https://www.xjbikes.com/forums/threads/1985-86-xj700-caliper-rebuild.118121/page-2


and a couple of good videos:


www.youtube.com/watch?v=njKRhPwHOaM

and

www.youtube.com/watch?v=0BrHublevTE

and






Here's a good image of a correctly set-up piston, with all of the seal and spring orientation done properly:

http://xjbikes.com/forums/index.php?threads/48360


And here's a helpful guide to doing it a rear master cylinder:

http://www.xjbikes.com/forums/threa...982-xj1100-maxim-rear-master-cyclinder.106588


NOTE1: be sure you very carefully clean and inspect your used, original master cylinder for any damage and rebuildability. If the pressed-in steel piston bore is badly scarred or pitted-rusted, then it must be honed to a silky-smooth finish before installing new components. If pits or scratches are too deep to be removed, it is best to obtain a replacement master cylinder (new or used) rather than to try to rebuild a damaged original. Remember, your life literally depends on your brakes....not always in day-to-day riding, but when it counts the most, in an emergency situation; and those always happen in the blink of an eye, and without prior warning.....


NOTE2: All original Yamaha front master cylinders have an extremely tiny "blow back" hole (actually a pressure release return passage) in the center of the bottom of the reservoir floor that must be clear and un-blocked in order for your master cylinder to function properly----if this hole is plugged, it will prevent the calipers from fully releasing when the brakes are NOT being applied, causing the brakes to always be slightly engaged. Brake system "dragging" will result, as well as brake rotor over-heating and warpage after a period of time.

This tiny hole is located within an area that is best described as what appears to be the beginning of a drilled hole that was "never completely drilled through" (this will make sense when you actually view the floor of the reservoir). In the very center of such area is this pressure release passage, and it takes about 1-2 un-stranded strands of wire to poke through this hole and remove any debris or gunk. This hole is not the much larger reservoir-to-piston chamber fluid transfer hole, which is huge compared to this pressure-relief passage. The pressure relief passage hole is normally just to the "side" or "behind" the larger (1mm diameter) fluid transfer hole, and "in line" with the centerline of the piston chamber, but "behind" the fluid transfer hole, towards the brake hand lever side of the master cylinder.

When rebuilding your master cylinder, make sure that this tiny relief passage is free and clear! Failure to clean this passage fully is one of the major over-looked "gotch-ya!" situations that arise when rebuilding your master cylinder.


A good picture of this relief port on the conventional (handlebar-mounted) master cylinders can be seen at:

http://xjbikes.com/forums/index.php?threads/12529

while XJ750 Seca owners will have to look here:

http://xjbikes.com/forums/index.php?threads/14836



Fluid Sight Window Replacement:

http://www.xj4ever.com/choosing a sight glass.pdf

and

https://www.xjbikes.com/forums/threads/1985-86-xj700-caliper-rebuild.118121/page-2

and here is a good video showing the basic (generic) installation of a sight window:

www.youtube.com/watch?v=F_yo3FnH6DM



- SIZE MATTERS:

If you are considering upgrading from one size master cylinder (piston bore diameter) to another, here's some decision parameters that you'll want to consider:

- Using a larger-than-stock bore master cylinder will result in a stiffer handle, and less lever “feel”, since more fluid is being moved with a same movement of the hand lever. It will be “hair-trigger” as far as responsiveness goes. Also note that upgrading to braided steel brake lines will also increase lever stiffness due to the lack of fluid passage “swell” in such brake lines.

- Using a smaller-than-stock bore master cylinder will result in an easier-to-move handle, and with more “feel” (since the lever has to be moved further to displace as much fluid as the original smaller m/c did). HOWEVER, in no case do you want to downsize so much that a full lever stroke does no deliver enough fluid volume to the caliper(s)! Typically, smaller-bore master cylinders can also have a smaller-capacity reservoir, so this can become an issue if using a smaller-than-stock bore m/con a dual-caliper and/or a multi-piston caliper.

More at:

http://www.airheart-brakes.com/pdfs/MasterCylinder_Selection.pdf

and

http://www.vintagebrake.com/mastercylinder.htm



- BRAKE FLUID:

Which type should you use? Good question! Here's a bit of an answer:

http://www.motorcycleproject.com/text/brake_fluid.html

NOTE: Yamaha specifies the use of DOT #3 brake fluid for all XJ models, but of course, that recommendation was made almost 25 years ago.........



- THE BLEEDING EDGE:

The master cylinders on these bikes push a very small amount of fluid with each hand stroke, and thus bleeding an empty system can be a long, time-consuming chore----but, on the positive side, it's a really great way to build up a really strong, firm, manly handshake and grip. But there's other ways and times to accomplish that, so when all you want to do is bleed your brakes, then there's nothing better than these labor-saving tools.


NOTE: hand-bleeding a dry system...such as when you change brake lines, or have rebuilt the master cylinder or calipers....is next to impossible to do without the use of a pressure or vacuum system. It will take you hours to do by hand. And here's why:

https://www.xjbikes.com/forums/thre...o-your-yamaha-today.4769/page-416#post-682247

With a vacuum bleeder system (such as a Mity Vac), you'll do it in about 10 minutes, tops.


Hints:

a) Make sure you don't run out of fluid in the reservoir when using these tools!

b) Make sure that your caliper bleeder screws are clean and pass fluid freely (and continue to do so once the system is evacuated) as old debris in your brake system settles down to the lowest point in the system (the caliper reservoir) and gets sucked into the bleeder screw during bleeding, this clogging the system and making it impossible to bleed.

c) Finally, here's one neat trick to get a truly professional, world-class level of brake bleeding accomplished: after you "finish" your final bleeding cycle, turn the forks so that the caliper you are bleeding is on the high side. Now do one final bleeding to rid the system of the last few tiny bubbles that tend to hide in the top of the caliper when the front wheel is straight ahead. The reason for this is: if you look at where the bleeder screw is on the caliper body, it is placed just slightly below the very top arc of the piston bore in the caliper. Turning the front wheel gets the internal bleeder screw port above this arc, and allows you to get all that pesky air out of your system!

And here are some other great tips for making this job easier:

https://www.xjbikes.com/forums/thre...o-your-yamaha-today.4769/page-416#post-682247

http://www.xjbikes.com/forums/threads/bleeding-front-brake-help-moved-from-dyi.111186

http://xjbikes.com/forums/threads/brake-bleeding-2-days-in-no-results.27670

http://www.xjbikes.com/forums/threads/bleeding-front-brake-fyi.110663

http://www.xjbikes.com/forums/threads/another-xj750-seca-brake-bleed.103363

http://www.xjbikes.com/forums/threads/86-xj700-brake-bleed-issue-resolved.118163

http://www.xjbikes.com/forums/threads/86-xj700s-brake-bleed.118135

http://www.xjbikes.com/forums/threads/bleeding-brakes.117886

http://www.xjbikes.com/forums/threads/this-brake-is-refusing-to-bleed.117322

http://www.xjbikes.com/forums/threads/bleeding-xj750-seca-brakes.115517




- BRAKE SWITCH REPLACEMENT:

How do you get that little switch out of the master cylinder (or clutch lever perch)?:

http://xjbikes.com/forums/index.php?threads/38144

 

CARBS and FUEL SYSTEM:

RICH, LEAN, or possibly even ritually UNCLEAN or OBSCENE: THE CARB REBUILDING FAQ:

Let us begin by warning you: an engine that is out of synch may perform AS IF it has a lean, or a rich, or a hanging idle, or a no-idle, or a run-away idle, or any variety of different conditions------if your engine (carbs) have not been synched, then that at is the #1 issue that you should attend to first, before you even READ any of the guidelines below and go and try to adjust and fiddle with things and change settings THAT AREN'T THE CAUSE OF THE REAL PROBLEM!!

And here are a couple of very good visuals of how a Hitachi or Mikuni CV ("constant velocity") carb actually works. For those of us who are not intimately familiar with these carbs, these videos provide a great basic understanding of what is actually "going on" with your carbs:





https://www.youtube.com/watch?v=2QhlYRDWjeY


Now here is another interesting video: a fully see-thru operational carburetor. Although a lot of it is somewhat tedious to listen to, the video is great demonstration of the basic concepts of how a carb operates, and especially how the fuel becomes “atomized or aerated” (vapourized) by the airflow thru the carb throat (the venturi).

https://www.youtube.com/watch?v=toVfvRhWbj8

However, note that the following items are missing from this basic set-up, and hopefully you’ll be able to visualize where and how the placement of the following items will modify (improve) the behavior of this simplified carb:

- no pilot fuel circuit.
- no replaceable jets to regulate the amount of fuel coming thru the main fuel circuit (or, thru the missing pilot fuel circuit).
- no vacuum piston or attached needle to (also) further regulate (control) fuel flow thru the main fuel circuit (in response to varying vacuum conditions present in the engine)…….this is a lawn tool engine, so basically after start up, it runs at a more-or-less constant speed (rpm’s), as opposed to our engines.
- no emulsion tube with its little holes in the shaft to pre-aerate the fuel mixture coming up thru the main fuel circuit.
- the system shown has a true “choke” system for cold-starting (it “chokes” or closes off the air supply thru the carb), complete with a separate, secondary butterfly valve system. On our engines, the carbs use a “starter” system which operates the same as the main or pilot fuel circuit does, but via a different passage and control mechanism…..no independent butterfly valve, no “choking” off of the air supply, no need to open the throttle valve to increase the airflow thru that closed (“choked”) passageway in the carb……rather, the “starter circuit” on Hitachi and Mikuni carbs simply open and close (via the choke plunger valves) a fully separate source/passagway of fuel from the bowl, and thus let none, a little, or a lot of extra fuel into the carb throat. And please never mind that the label on the left control switch says “CHOKE”…………



Question #1: Why Isn't It Running Right?:

Below is a semi-useful "general rules-of-thumb" list to help you recognize and diagnose fuel-mixture problems.

All of these descriptions assume that the carburetors are cleaned and operating properly, are stock (no jet kit), the valves are adjusted properly, and the engine has been synched.

If any of the above procedures, tasks, actions, or activities have NOT been checked or performed, then do them first, or otherwise all your other efforts will barely even give you "casino odds" at striking it rich and determining what the real cause(s) of your symptoms are......



Typical Symptoms and Causes of a Lean Fuel-Mixture Condition:

- Poor acceleration; the engine feels flat.

- The engine won't respond when the throttle is snapped open, but it picks up speed as the throttle is closed. (A too-large main jet also mimics this symptom.)

- Idle speed falls after you blip the throttle, then creeps back up.

- The engine runs hot, knocks, pings and overheats.

- A lean pilot circuit condition can be responsible for a creeping or hanging high idle, where the rpms stay high then slowly drop down to the set point.

- The engine surges or hunts when cruising at part-throttle.

- Popping or spitting through the carb occurs when the throttle is opened. Or popping and spitting occurs through the pipe on deceleration with a closed throttle.

- The engine runs better in warm weather, worse in cool.

- Performance gets worse when the air filter is removed.

- Fuel levels that are too low will cause a lean condition.

- In cases where an overly lean fuel condition is suspected, the application of a small amount of "choke" may decrease or eliminate the symptoms.

- Here's the main reason you don't want to run lean over an extended period of time:

http://www.xjbikes.com/forums/threads/head-gasket-1982-maxim-650.85273/#post-504365

A holed piston. Notice how it's right where the plug fires (the hottest point anyway, and made ultra-hotter by a lean fuel condition).



Typical Symptoms of a Rich Fuel-Mixture Condition:

- Engine acceleration is flat and uneven and loses that "crisp" feel.

- The engine "eight-strokes" as it loads up and skips combustion cycles.

- The engine's idle is rough or lumpy, and the engine won't return to idle without "blipping" the throttle.

- An overly rich pilot mixture is usually the culprit when the idle drops low then slowly recovers.

- The throttle needs to be open continuously to maintain acceleration.

- Black, sooty plugs, a sooty exhaust pipe and black smoke from the tailpipe that stinks of unburned fuel.

- Poor fuel economy.

- The engine works better when cold. Performance falls off as it warms up or the ambient temperature rises.

- Engine performance improves when the air cleaner is removed.

- Fuel levels that are too high will cause a rich condition, as will a choke system that is slightly hung open or has leaky plunger valves.



Some common causes of a high idle:

- Engine has not been synched, as each cylinder "fights" the others for dominance, it can lead to a run-away idle situation.

- A lean air-fuel mixture condition, which can be caused by a variety of problems......vacuum leaks, plugged or too-small fuel jets, etc. Old or "stale" gas may also cause a lean fuel-air mixture to occur temporarily (until the fuel is used up!).

- A vacuum leak somewhere in the intake system.....intake boots, internal o-ring seals, etc.

- Mixture screws not properly set or adjusted.

- Vacuum piston sticking or stuck in a partially raised position.

- Idle speed screw set too high, or set to create a "proper" idle speed when the engine was cold (and thus results in a "high idle" once the engine reaches operating temps). The idle speed when the engine is cold should be modulated via the use of the choke (enrichment) control system.

- Butterfly valves opened too far; synch screws out of adjustment.

- Throttle cable wear, adjustment, or throttle lever brackets installed incorrectly or interfering with other nearby objects (cylinder head fins, etc.).

- Choke (enrichment) circuit is stuck "open"....this can occur even if the choke lever is rotated to the fully closed position, if for some reasons the choke plungers are not fully closing (cable wear, cable adjustment, bent finger brackets, or installation problems). In addition, even if the choke plungers are "closing" fully, if the choke plunger valve face or its seat are worn or scarred, this will allow fuel to leak part the plunger and richen the mixture even if the plungers are closed.



Some common causes of a “run-away” idle speed:

If the idle speed starts building and building and eventually “runs-away” to a level that will grenade the engine without you shutting it off:

https://www.xjbikes.com/forums/thre...-no-vacuum-leaks-detected.120948/#post-607986


This is typically caused by an out-of-synch condition:

https://www.xjbikes.com/forums/threads/82-xj-650-startng-problem-surpise.46358/page-2#post-414262


After reading all of the above, you should by now know the solution……….. 



Why your engine seems to be schizoid:

A hanging idle---one that stays high and slowly comes down when decelerating---is a sign of lean mixture. The opposite case, where the idle drops dangerously low then rises, is a sign of rich mixture.

A bike that runs better when hot is probably lean, and a bike that runs better when cold is probably rich.

But sometimes a bike that can be adjusted "just right" when cool, but actually starts exhibiting signs of running lean (hanging idle) as it warms up. And if the idle speed is then re-adjusted while the engine is warm, but eventually falls and the bike dies (especially when sitting at a stop light). Or if the pilot screws are adjusted, then it's too rich when cold---all in direct contradiction of the above observations.

Experience shows that this is a sign of worn throttle shaft seals.....the aluminum carb bodies expand with the heat, but the steel throttle shafts---resting comfortably in a nice cool airflow---don't heat up and therefore don't expand. Once the shaft seals get old and hard, they no longer are able to flex and fill the gap.....so the carb starts drawing air around the shafts, leaning it out.



Why does my engine sometimes backfire when I first turn on the key (without attempting to start the engine)?:

- When you kill the engine, the intakes will still have some remaining (un-burned) air-fuel mixture remaining in them. Upon powering up the bike (turning the key on), the ignition system will apply 12 volts to the coils, thus charging them. Of course, that constant current is not good for the coils, so few seconds later (if the engine is not started) the TCI shuts down the coils by grounding them (to protect the coils from overheating) which cuts the current to the coils and thus triggers a spark to the plugs. If there is enough un-burned fuel in the intake manifolds or the combustion chambers, and if the valves are held open by the camshafts, a backfire thru the exhaust header and/or thru the intake manifolds/carbs/airbox can result.



Why are my plugs carbon-fouled (dry, sooty black deposits)?:

- Carbon fouling is the result of incomplete combustion----for any reason. It is most often associated with an overly rich fuel mixture (whatever the cause), but can also be caused by an overly lean fuel mixture (or poor spark, etc.) In a lean-mixture condition, most of the un-burnt mixture gets pumped out the tailpipe, but some fuel droplets remain in the cylinder and add themselves to the next intake charge. That's not a very precise way of metering the mixture, so when it's finally rich enough for a spark to ignite, that particular charge may be too rich, resulting in incomplete combustion and plug fouling. So carbon-fouled plugs can be due to rich or lean conditions.......your Colortune spark plug will tell you for sure. If you have a light blue or white-ish flame, intermittent flame, and/or intermittent flashes of yellow within an otherwise white-ish flame, then your fuel mixture is too lean.

And by the way.........if the spark that happens to ignite this overly-rich mixture is the "wasted spark" (which occurs in each cylinder at the top of the exhaust stroke,, it will occur JUST AS THE INTAKE VALVE IS OPENING ---- so the backfire pressure wave may be directed back up the intake tract!



Why are my plugs oil-fouled (wet, oily black deposits)?:

- worn or broken piston rings, excessive wear or damage to cylinders, *leaking intake valve stem seals.

* while bluish smoke from the exhaust can be caused by worn exhaust valve seals, that situation will not foul your spark plugs. Consider what happens: oil pools above the valve guides, and coats the valve stems every time they rise. These stem "seals" really aren't seals, they are more like wipers, and their function is mainly to wipe off the excess oil from the valve stem. Now, when these stem seals get old and hard, they leave an excess amount of oil on the valve stem, which then drops down into the path of the exhaust gas flow as the valve opens and the oil is evaporated off, leaving blue smoke from the exhaust. But note that none of that oil ever enters the combustion chamber, so it can't foul the plugs.

Of course, any excessive oil coating an intake valve stem will end up going through the cylinder, but intake valve stem seals rarely fail on these engines. Unlike the exhaust valves, which are constantly baked by superheated exhaust gas, the intake valves are bathed in cool and moist (with gasoline) air.



Why is the inside of my carbs covered with a brownish-green goo?:

When fuel mixes with water and sits around for a while, this is the result. Nasty looking, nasty smelling, and you can bet that the tiny passages inside the carb body are plugged solid with this stuff! Definitely time for a full rebuild.......



I have an XJ650 Turbo and......:

Here's a really great discussion on some Turbo fuel system problems, which are even more frustrating than carb problems on all of the other models:

https://www.xjbikes.com/forums/threads/weird-problem-on-my-yamaha-xj650-turbo.130408/#post-664092



Question #2: What Parts Will I Need?:

The parts you'll need depends on what is there, what is missing, what is worn out, what gets broken or damaged during the dis-assembly process, etc., but the "basic items" needed for the rebuild process (besides any special tools and tuning equipment) is as follows:

- throttle shaft seals (you'll have to split the carbs from the rack to replace these).

- fuel supply tube o-rings (you'll have to split the carbs from the rack to replace these) on the models that use them (some Mikuni carbs do not use these).

- float valve needle and seat rebuild kit (seat, needle, clip, seat washer. The float valve seat filter screens are also available separately). Mikuni owners will also want to replace the float valve seat o-rings.

- float bowl gaskets.

- idle mixture washers & o-rings for sure, and the idle mixture screw springs and mixture screws if they are damaged.

- jets, if damaged or incorrectly sized.

- carb bowl fuel drain screws, if damaged.

- new replacement carb hardware (screws, etc.)---now is the time to upgrade to stainless steel and/or allen-head fasteners if so desired!



From Our Experience:

Since the carburetors are THE most troublesome (and thus most expensive) aspect of these bikes, let me offer a few dozen words and insights about them, their service, and expense:

These carbs are quite simple, mechanically speaking.

The process of making DARNED SURE that you get them unbelievably, positively zestfully clean is a matter of stick-to-it-ness and resisting all attempts to take "shortcuts" or to brush off the tedious aspects of it. Many of the passages in these carbs are tiny, and it's that "tiny-ness" that bites most people, as they don't want to or don't realize the amount of effort that has to be undertaken to deal with such small passages.

If you read through these forums, you'll see many tales of woe of people who are now "cleaning" their carbs for the 2nd, 3rd, or 4th time BEFORE they get it right. The problem is, they never really "cleaned" them correctly the first, 2nd, and 3rd time. After all of the frustration and hassle involved, by the time they get around to the 4th go-around, then they understand that when people who have SUCCESSFULLY rebuilt carbs say things like "you'd better make SURE that you get clear flow through each and every passage, and you'd better polish that piston diaphram bore", etc. aren't just saying that to be over-the-top retentive about their own habits and style of working on these carbs, what they're really doing is issuing an experienced WARNING: do it right, or keep doing it again, and again, and again. And although they're kind of fun little critters to play with, taking them all apart and putting Humpty Carby all back together again, well, it's time better spent on other things.


Think we're kidding? The following thread is a "must read", because the title says it all:

http://xjbikes.com/forums/index.php?threads/17821


One last note: "cleaning" the carbs (internally, not just making them look pretty on the outside) is just one of the small subsets of tasks necessary to the proper REBUILDING of the carbs. I cannot stress this point enough. The use of the term "cleaning" is used as if it were the end goal of the process; in reality, the proper way to think about it would be this:

"A complete and exceptional level of carb CLEANING is a vital and necessary part of the process of properly REBUILDING the carbs."

And what are the other components of the rebuilding puzzle?

a) getting the darned things off the bike! This might help:

http://xjbikes.com/forums/index.php?threads/29695

and

http://www.xjbikes.com/forums/threads/made-a-how-to-video.103484/


b) replacing the worn, missing, or necessary "wear parts" on the carb.


c) Proper "service" work to the carb bodies, especially:

- polishing the piston bore for silky smoothness.
- repair or clean up of any stripped threads in the carb bodies.
- replacement of any damaged or worn parts. In fact, the ability the recognize what is damaged and worn (besides the parts above which are designed to wear out) is the most difficult part of the entire task, since it requires a level of experience: are my needle tips worn? What, exactly, does a worn needle tip look like? How "smooth" is smooth enough? Etc. This is where the advice and experience of the members of this forum are invaluable.


d) Proper "settings" of the various components during re-assembly:
- the fuel levels (float heights).
- the "basic or bench synch" of the throttle valves:

If your carbs have been removed from the engine for a rebuild, it is suggested that a “bench synch” procedure be performed, which does not require any tools to perform….the only purpose of the bench synch procedure is merely to get the carbs set up “close enough” to allow the engine to start and run, at which time a running (vacuum) synch of the engine should be immediately performed, using the HCP96Q synch gauges, A great visual guide to the bench synch process can be seen at:

http://xjbikes.com/forums/index.php?threads/6366


e) On-bike "settings":

- first and foremost, the measurement and setting to specifications of the valve train (shim) clearances. Failure to do this "wastes" 90% of your efforts involved with the carbs.
- final synch (using some type of manometer and the YICS tool if your engine is YICS-equipped)
- idle mixture screw setting, preferably using a Colortune plug.


One last thought about these carbs, since they are THE most troublesome aspects of these bikes, and something to consider:

- the four carbs concept is really neat looking, and is certainly performance-oriented to the extreme.

- for many of us who had lots of experience with automotive carbs, just beware that while these Hitachi and Mikuni carbs are a bit different in operation (and thus parts), a carb is a carb, and they're pretty basic little devices. The main difference is that the fuel circuit passages on these carbs can get bizarrely tiny, especially if you're used to working on automotive carbs (which have canyon-sized fuel passages compared to these carbs).

- like I've said, the cleanliness part is really just tedious work, with a couple of "tricks" thrown into the mix, given the small sizes you're having to deal with. The "rebuild" part is basic mechanical knowledge and skills, knowing which way to turn a screwdriver to loosen vs. tighten, when and how much force to use or not, being organized, stuff like that.

- but the "tuning" part will require some special tools, but no type of any rocket-science knowledge or skills----once you master the rebuild and tuning process with these bikes, you are pretty much a Carb Tuning God, as these carbs are about as "complicated" as it gets with carburetors. I mean, VERY few vehicles have multi-carbs, not until you get to the really high-performance machines level in the automotive world.

- well, as "complicated as it gets" until you start adding pods, etc.----which if you do, I sure hope you've got every last one of the basics listed above down to a science, and you can do it all, properly, and blindfolded, too!

- finally, if you do not have a service manual(s) for your particular bike(s), and you're going to wrench on it and want to do things right, then the only thing I can surmise from such a course of action is:

a) you're already an expert, or.....

b) you aren't really serious about doing things right, and that's okay, too---just don't expect good, quick, or cheap results!



The following guide may save untold hours of frustration and grief:

http://www.xjbikes.com/forums/index.php?threads/in-the-church-of-clean.14692/




- REMOVING THE DARNED THINGS!:

http://xjbikes.com/forums/index.php?threads/29695

and

http://www.xjbikes.com/forums/threads/made-a-how-to-video.103484/




- CARB REBUILDING BASICS:

http://www.xjbikes.com/forums/index.php?threads/in-the-church-of-clean.14692/

and

http://www.xjbikes.com/forums/index.php?threads/the-secret-life-of-carburetors.14751/




- CARB REBUILDING ADVANCED ---- X-RAY VISION!:

http://www.xj4ever.com/inside your carbs.pdf




- HITACHI CARB REBUILDING:

http://xjbikes.com/forums/index.php?threads/3649

and

http://www.xj4ever.com/hitachi throttle shaft seals.pdf



- MIKUNI CARB REBUILDING:

http://xjbikes.com/forums/index.php?threads/3633

and

http://xjbikes.com/forums/index.php?threads/3690

and

http://www.xj4ever.com/mikuni carb cleaning.pdf

and

https://thexscafedotcom.files.wordpress.com/2014/06/mikuni_bs-cv_carburetor_rebuild_tutorial.pdf

Note that the above link shows the rebuild for the BS28 series of Mikuni carbs (same as on XJ550 models) that are off a Suzuki, and while some minor differences exist ( i.e the choke plunger system and the locknuts on the synch screws), 99% of the information (and pictures) will crossover to the XJ550 model carbs.

and

http://xjbikes.com/forums/index.php?threads/31061

Note that the above link shows the exploded view of the BS28/BS30 series of Mikuni carbs (used on XJ550 and XJ650 Turbo models);, the BS33-and-larger series move the pilot air jet from under the vac piston diaphram to the carb throat.........and have the choke plunger coming out of the side of the carb body rather than the top.


Always remember to take copious notes as you are disassembling your carbs, or otherwise you will forget some important details when it’s time to put those Humpty-Dumpty’s back together again. For example, would you remember how to re-install the throttle closure springs correctly if you didn’t have this?:

http://xjbikes.com/forums/index.php?threads/18093



- CARB VACUUM PISTON OPERATION:

Having the carb piston bore fully polished is an incredibly important task when rebuilding a set of carbs, as any restriction to the free and almost friction-less movement of the vacuum piston will create a variety of performance-related problems. You can review this issue (the vacuum piston "CLUNK TEST") at:

http://xjbikes.com/forums/index.php?threads/1640

and see a nice video of a clunking piston at:



And the reason you want your vacuum pistons to operate as closely as possible to a "zero-resistance" state is because they must be able to perform, constantly, in the following manner; and if not, tuning and performance becomes troublesome or downright impossible:




Note closely the difference in vac piston operation between a no-load condition:



and how they operate under load:

https://www.youtube.com/watch?v=PoEo-KrMTA0



- THROTTLE SHAFT SEALS and SCREWS:

NOTE: these throttle shaft retaining screws are an absolute BEAST to remove, and it is very easy to destroy the screw heads as well as the throttle shaft threads while trying to remove them---if proper precautions are not taken. You will want to review the information in this forum thread before attempting removal:

http://xjbikes.com/forums/index.php?threads/8011

and

http://xjbikes.com/forums/index.php?threads/17628

and

http://www.xj4ever.com/hitachi throttle shaft seals.pdf



- CARB ENRICHMENT ("CHOKE") CIRCUIT CLEANING:

http://xjbikes.com/forums/index.php?threads/8918


P.S. how do you know when your starter jet is really, truly, zestfully clean? One of two ways:

a) shine a strong penlight or mini flashlight into the bottom of the bowl, where this jet passage "intake" is located. Look through the top of the bowl down into the jet passage "outflow" passage (this is the passage that the brass suction tube in the bottom of the carb body actually fits down into). Focus your eye carefully on the jet opening and make sure it's clean. P.S. it helps to do all this while in a darkened area.........see the picture "starter-jet.jpg" on page 2 of this forum thread topic for a great image of what you want to see!:

http://xjbikes.com/forums/index.php?threads/4050


b) put the spray tip (you may have to gently shape the end of it to a fine point, see the video below) of a can of carb or brake cleaner into the intake opening of the starter jet and let rip a spray. A STEADY, FINE, POWERFUL STREAM OF FLUID WILL COME OUT OF THE OUTFLOW PASSAGE ON THE TOP OF THE CARB BOWL IF THE JET IS PERFECTLY CLEAN AND OPEN. I mean this stream will absolutely spit out a good 5-10 feet. If the stream isn't powerful and laser-like precise coming out of the jet, then the jet isn't zestfully clean.....


By the way, when using the spray-stream method of checking the jet, don't even THINK of putting your eye or face anywhere even NEAR the jet outflow path, unless you like a painful and potentially serious trip to the emergency room.




- CARB PILOT MIXTURE SCREWS --- ALL YOU EVER WANTED TO KNOW ABOUT THEM:

http://xjbikes.com/forums/index.php?threads/18265



- CARB PILOT MIXTURE SCREWS STUCK?:

You're not alone.........

http://xjbikes.com/forums/index.php?threads/32017



- CARB PILOT FUEL CIRCUIT --- IT'S TINY, IT GETS CLOGGED INTERNALLY, AND WHAT TO DO ABOUT IT:

Q: and how do you know when your pilot fuel circuit is really, truly, zestfully clean?

Ensuring that your pilot fuel circuit is internally clear and free is one of the most difficult tasks to perform on these carbs due to its incredibly small size (so fuel varnish will accumulate and solidify in there over time):

http://www.xj4ever.com/inside your carbs.pdf

To make sure that your internal pilot fuel circuit is truly “zestfully clean” after your clearing efforts:

1. Drill out an old pilot fuel jet so that the straw from the carb cleaner fits snuggly in the hole (or some other suitable method of “sealing off” a straw into the pilot fuel jet passage where the jet screws into the carb body).
2. Leave the pilot air jet in, but block it off with a wooden q-tip that is covered with a bit of heat shrink tubing (or use your finger to firmly block it off).
3. Install the pilot screw without its o-ring, and set it to about 2.5 turns out from soft bottoming.
4. Blast the carb cleaner through the modified pilot jet and it should look something like this:

https://www.youtube.com/watch?v=5Qr2Y6G2Ejg

By the way, when using the spray-stream method of checking the jet, don't even THINK of putting your eye or face anywhere even NEAR the jet outflow path, unless you like a painful and potentially serious trip to the emergency room



- CARB EMULSION TUBES (a/k/a "MAIN NEEDLE JET") OPERATION:

Called by a variety of names, the main fuel jet tube is technically known as the MAIN NEEDLE JET, although they also go by the name of "power valves", "emulsion tubes", or some choice four-letter words while you are trying to remove them from their bore hole in the carb body! These 2" long brass tubes have a series of very precise, very small holes that actually atomize the fuel from the main fuel jet around the jet needle, and are what provide the final, precise metering of the fuel mixture through the main jet.

https://www.youtube.com/watch?v=IGPg51AtIEE

Commonly clogged and dirty-filthy beyond belief, they are easy to damage while removing them or during the cleaning process. If the holes are enlarged, if the end of the tube (where the needle enters it) worn or egg-shaped, or if the threads in the jet end damaged, these nozzles should be replaced, or your bike will never run properly.



- CARB BOWL DRAIN SCREWS STUCK?:

You're not alone, either.........

http://xjbikes.com/forums/index.php?threads/4281




- CARB FUEL LEVEL SETTING:

Here's the proper fuel-level settings by model when using the "clear-tube" method of measurement:

Hitachi all HSC32 series models:

NOTE: all of the following models used HSC32 carbs:
XJ650 Maxim, Midnight Maxim, XJ650RJ Seca (non-turbo), XJ650 Euro all use HSC32 carbs (various versions)
XJ750 all USA 1981-83 models use HSC32 version 5G200 (Seca) and 15R00 (Maxim and Midnight Maxim)
XJ750 all Canadian 1981-83 models use HSC32 version 5H200 (Seca) and 15T00 (Maxim and Midnight Maxim)
XJ750 UK/Europe 11M models, XJ750 Police models 24L and 37H use HSC32 version 5N100

-Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches)

-Float height: 17.5 +/- 0.5mm


Hitachi HSC33 series (XJ700 air-cooled models):

-Fuel level measured via the clear-tube gauge: 1.0mm +/- 1mm (.039" +/- .039")

-Float height: 16.0 +/- 1.0mm


Hitachi HSC33 series (XJ750E-II model):

-Fuel level measured via the clear-tube gauge: 5.0mm +/- 1mm (.197" +/- .039")

-Float height: unknown


Hitachi HSC33 series (XJ750RL models):

-Fuel level measured via the clear-tube gauge: 1.0mm +/- 1mm (.039" +/- .039")

-Float height: unknown, but possibly the same as XJ700 air-cooled models (16.0 +/- 1.0mm)


Mikuni BS28 (all XJ550 except 1984 XJ550L):

-Fuel level measured via the clear-tube gauge: 2mm +/- 1mm (.08 +/- .039 inches)

-Float height: 21.5 +/- 1.0mm


Mikuni BDS26 (USA all 1992-98 XJ600 Seca II):

-Fuel level measured via the clear-tube gauge:
USA: 4 - 6mm (.016 - 0.24”) below float chamber line

-Float height: 6.2 - 8.2mm (0.24 - 0.32”)


Mikuni BDST28 (non-USA all 1992-98 XJ600 Seca II):

-Fuel level measured via the clear-tube gauge:
1992-96 Canada and Australia: 3 - 5mm (0.12 - .0.20”) above float chamber line
1992-95 UK: 3 - 5mm (0.12 - .0.20”) above float chamber line
1996-98 UK: 8.5 - 9.5mm (0.34 - .0.37”) above float chamber line

-Float height:
1992-96 Canada and Australia: 11 - 13mm (0.43 - 0.512”)
1992-95 UK: 11 - 13mm (0.43 - 0.51”)
1996-98 UK: 8.8 - 10.8mm (0.35 - 0.42”)


Mikuni BS32 (all XJ550L, 1984-85 FJ600, and 1984-87 / 1989-91 XJ600):

-Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches)

-Float height: unknown


Mikuni BS30 (all XJ650 Turbo):

-Fuel level measured via the clear-tube gauge: 2mm +/- 1mm (.08 +/- .04 inches)

-Float height: 21.0 +/- 0.5mm


Mikuni BS33 (all XJ700-X and XJ750-X):

-Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches)

-Float height: 17.5 +/- 1.0mm


Mikuni BS35 (all XJ900RK/RL):

-Fuel level measured via the clear-tube gauge: 5mm +/- 1mm (.20 +/- .04 inches)

-Float height: 22.3 +/- 0.5mm


Mikuni BS36 (all XJ900F, FN, N, etc):

-Fuel level measured via the clear-tube gauge: 5mm +/- 1mm (.20 +/- .04 inches)

-Float height: 22.3 +/- 0.5mm


Mikuni BS34 (all XJ1100 and XS1100):

-Fuel level measured via the clear-tube gauge: 3mm +/- 1mm (.12 +/- .04 inches)

-Float height:
25.7 +/- 1.0mm (1978-79 all models)
23.0 +/- 0.5mm (1980 all models)
not specified (1981-82 all models)


And here's the Holy Grail on this subject:

http://www.xj4ever.com/setting fuel levels.pdf

And here’s a good visual guide to some problems that you might run into:

http://www.xjbikes.com/forums/threads/setting-the-floats-mikuni-not-gettin-any-readings-fixed.40395

and here’s a wonderful video from TurpentyneTV that shows the whole process in excruciating detail:

https://www.youtube.com/watch?v=V8yu-WjcglY



- CARB PRELIMINARY "BENCH-SYNCH":

http://xjbikes.com/forums/index.php?threads/6366

and

http://xjbikes.com/forums/index.php?threads/43094



- CARBTUNE "SYNCH STICKS" USAGE:

http://www.youtube.com/watch?v=CYgN2-96Ik0&feature=related

http://www.xjbikes.com/forums/threads/running-sync-screw-in-or-out-that-is-the-question.75716/



- SYNCH AND YOU:

http://www.xjbikes.com/forums/index...rtng-problem-surpise.46358/page-2#post-414262



YOU'RE SCREWED:

In three different ways if you don't understand the basics:

https://www.xjbikes.com/forums/threads/how-to-bench-synch-your-carbs.6366/page-5#post-680464



- YICS SYSTEM SYNCH TOOL USAGE:

http://www.xj4ever.com/HCP5460 YICS tool.pdf



- COLORTUNE TUNING PLUG USAGE:

e) the above procedure is the only way to truly and properly "tune" a multi-carbed engine!


The following overview video show the Colortune Plug in action:

https://www.youtube.com/watch?v=9mKQvWM0nMg


going from orange (rich) to blue:

http://www.youtube.com/watch?v=6hFUvQ4gaPc

Note in the above video how much easier it is to see the combustion color, especially when looking at the plug “window” from off-center (i.e. looking straight down the centerline of the plug results in the actual spark color “diluting” the combustion color). Also note that it is being filmed in a dark area, making the “neon blue” color easier to observe than when observed in strong light.


Here’s a good one showing a colortune being hooked up incorrectly (arcing):

http://www.youtube.com/watch?v=VQ_mZJYIq8I&feature=related


And here's a super-sized colortune plug, don't try this at home kids!:

https://www.youtube.com/watch?v=9V9u1KvyM5k

https://www.youtube.com/watch?v=TVTfNSTR39o



- PREVENTING BROKEN CARB FLOAT PIN POSTS:

http://xjbikes.com/forums/index.php?threads/19168



- FIXING BROKEN CARB FLOAT PIN POSTS:

http://xjbikes.com/forums/index.php?threads/17843



- ORIGINAL FUEL PETCOCK REBUILDING:

A great visual journal of the original automatic petcock rebuilding process is documented at:

http://xjbikes.com/forums/index.php?threads/25058

or:

http://redirect.viglink.com/?format...ogle.com/open?id=0B_auMGwOqE1rVlBMN0xKRE9rSG8



- FUEL HOSE EXPLOSION!:

Seems like if one fuel line is good, then seven must be even better........... although the pictured carbs are from XJ900 models, the XJ700 model carbs suffer a similar fate.

http://xjbikes.com/forums/index.php?threads/27090

and

http://xjbikes.com/forums/index.php?threads/41355


XJ1100 and XS1100 Special/Midnight Special models use a remote vacuum control unit (separate from the fuel valves on the tanks) to provide the automatic on/off control of the fuel valves. This designs also leads to a plethora of fuel hoses:

https://www.xjbikes.com/forums/threads/new-to-me-xj1100.124416/#post-625737




- FUEL TANK SWAPS:

Bolt-on tank interchanges:

All XJ650 (except Turbo) and 1981-83 XJ750 (except XJ750RL) tanks will swap between those models and fit, but may experience some minor interference issues with the front of the seat/seat pans. Many XJ650 Maxim and Midnight Maxim owners like to upgrade to the larger XJ750 Maxim tanks, and that is basically a bolt-on swap.

XJ750RL (1984) and XJ900 tanks are basically identical and will swap easily.

All XJ550 tanks (Maxim and Seca models) will interchange with each other.


[n/Tanks that will not interchange at all or without a LOT of work[/b]:

All XJ550 tanks (Maxim and Seca models) will interchange with each other, but will NOT swap with XJ650 or above models (the tank mounting dimensions are different). XJ700 and XJ750-X tanks will NOT interchange with any other models. XJ650 Turbo tanks will NOT interchange with any other models. XJ750RL and XJ900 tanks will NOT interchange with any other models.


Further insights into tank-swaps can be reviewed at:

http://xjbikes.com/forums/threads/m...rily-550-seca-and-650-seca.47996/#post-426801

and

http://www.xjbikes.com/forums/threads/80-to-83-seca-fuel-tank.49765


And if you want to increase the rather small fuel capacity of your XJ700 or XJ750-X tank, here's the correct way to do it:

http://www.xjcd.org/maximized-X



- FUEL TANK INTERNAL RUST REMOVAL AND SEALING:

For most owners, replacement fuel tanks are not available, and so the issue becomes "how to de-rust" an original tank. Although there are a variety of methods which can be used, there are plus-and-minus considerations to each method or technique.

Here are a few other good ways to de-rust metal products:

- soak iron (steel) parts in heated vinegar (doesn’t matter what kind) overnight, then rinse with clean water. and finally spray with fogging oil (or similar) to prevent rust from re-forming.

http://www.mopedarmy.com/wiki/Removing_rust_from_a_gas_tank

http://users.eastlink.ca/~pspencer/nsaeta/electrolysis.html

http://www.moreg.org.au/dissolving_rust.htm

http://www.htpaa.org.au/article-electro.php

http://xjbikes.com/forums/index.php?threads/32838

http://xjbikes.com/forums/index.php...val-no-frills-easiest-fastest-cheapest.48196/

http://www.robertscycle.com/chrome-clean.html

http://www.xjbikes.com/forums/threads/teds-2nd-82-xj750-maxim-bobber-project.47929/#post-478002

http://www.practicalmachinist.com/vb/general-archive/rust-removal-using-molasses-90452/



- REBUILDING YOUR FUEL TANK CAP: IT’S A GAS, GAS, GAS:

A great visual tour of the internal bits and pieces (and the rebuild process) for the original pop-open gas caps can be seen at:

http://www.xj4ever.com/gas cap.pdf

And now with video:

https://www.xjbikes.com/forums/threads/gas-cap-complete-clean-rebuild.120698/

or:

https://www.youtube.com/watch?v=3CSnBc6hf3s


A great visual tour of the internal bits and pieces (and the rebuild process) for the original twist-open gas caps (FJ600, XJ650 Turbo, and XJ900) can be seen at:

http://www.xj4ever.com/turbo gas cap rebuild.pdf



- THE SECRET LIFE OF FUEL SENDING UNITS:

https://www.youtube.com/watch?v=re5NdBmPgiY



- AIR FILTER ELEMENTS:

Filter, filter in that hole,
Who's the fairest of them all?

http://www.motorcycleproject.com/text/air_filters_more.html

and

http://www.motorcycleproject.com/text/powersports_air_filters.swf


Yamaha specifies a service life for stock pleated-paper air filter elements under "normal" conditions as being approximately 15,000 miles.



- WHAT ABOUT PODS?:

It's a question we get asked often and unfortunately, one that we cannot answer honestly about your specific bike besides with "it depends".

Which is a nice way of saying "you're about to enter the seventh circle of hell......."!

Carb jet tuning required by aftermarket modifications is somewhat of a black art, part science, part skill, part luck. It depends on the current state of tune of your engine, your altitude, the mix of aftermarket parts on your bike, etc........a lot of variables.

The best advice we can offer is: Just Say No!. Don't do it! Leave everything stock!

But, since most people---with good reason, I might add---don't always listen to our well-intentioned advice, then the next best recommendation we can offer is: "if you want more power get a bigger bike!".

And since that doesn't cut it with many owners, either, for the remaining stalwarts out there who insist on "experimenting" with aftermarket intake and exhaust systems, here's the best information that we've come across to give you some GUIDANCE, which you should take as just that, and not as ANSWERS, because it isn't!

Definitely not plug-and-play:

https://www.youtube.com/watch?v=Vt6HtsggcqU

And some pod filters make a difficult situation even worse.........read all about it:

http://www.caferacer.net/forum/technical/19639-pod-filter-thread-geeto.html

Yoji himself cautions against it:

http://xjbikes.com/forums/index.php?attachments/mikuni-article-jpg.15101



MAIN FUEL JET SIZE CHANGES NEEDED PER TYPICAL MODIFICATION:


Typical Exhaust Changes:

+2 main fuel jet size for custom 4-into-2 exhaust

or

+4 main fuel jet sizes for 4-into-1 exhaust

or

+4 main jet sizes for no muffler (open headers)


Typical Intake Changes:

+2 main fuel jet sizes for single K&N filter (inside a stock airbox)

or

+2 main fuel jet size for drilling holes in the airbox with stock filter

or

+4 main fuel jet sizes for individual pod filters (no airbox)


Additional changes:

- Add up all the main fuel jet size increases and subtract 2 sizes.

- Decrease main fuel jet size by 2 sizes per every 2000' above sea level.

- Under a mis-match condition, such as when using pod filters with a 100% stock exhaust, or 4-into-1 header with stock filter and air box, then subtract 2 main fuel jet sizes.



PILOT FUEL JET SIZES CHANGES NEEDED PER TYPICAL MODIFICATION:

Pilot fuel jet size changes are related only to the change in main fuel jet sizes according to the main fuel jet size formula described above. Note that this pilot fuel jet rule is for the main fuel jet size change BEFORE any main fuel jet altitude compensation is factored in:

Increase the pilot fuel jet size +1 for every +3 main fuel jet size increases.

Additional changes:

- Decrease pilot fuel jet size by 1 for every 6000' above sea level.



PRECAUTIONS:

- Make sure your carbs are in perfect working order before making ANY jet changes....meaning fully cleaned internally and rebuilt, operating properly in their stock configuration, proper sized air jets and needles, etc. Otherwise, you'll like find that all of your efforts are going to be a HUGE waste of time.

- Check plug color often and adjust as needed, 2 main fuel jet sizes at a time and 1 pilot fuel jet size at a time. Bright white plug insulators are a sign of an overly lean fuel mixture condition and WILL cause damage to your engine over time, up to and including engine seizure!

- Synch the carbs after each jet change.

- Make sure the floats are set correctly

- Seriously consider purchasing a Colortune Plug Tuning kit.

- You may find it necessary to make changes to the size or shimming of the main jet needle. There are no guidelines on what or how to do these changes, this is true trial-and-error tuning!



EXAMPLE:

A 1982 XJ750RJ Seca using an aftermarket Supertrapp 4-into-1 exhaust and a single K&N air filter in the stock, unmodified airbox. Bike is primarily operated at an altitude of 2600 feet above sea level.

XJ750 Seca Stock Hitachi HSC32 Carb Jetting:

#120 Main Fuel Jet
#40 Pilot Fuel Jet
#50 Main Air Jet
#225 Pilot Air Jet
Y-13 Needle


MAIN FUEL JET SIZE CALCULATIONS:

Changes made:

Exhaust:
4 into 1 with Supertrapp = +4 Sizes Main Fuel Jet

Intake:
K&N Pod Filters = +4 sizes Main Fuel Jet
----------------------------
Equals: +8 main fuel jet sizes above baseline
Subtract: -2 main fuel jet size per formula above
----------------------------
Equals: +6 main fuel jet sizes due to modifications, thus:

Stock main fuel jet size is: #120
+ 6 additional sizes
= a #126 main fuel jet size
---------------------------
Subtract: -2 main fuel jet sizes for Altitude of 2500' Average

= #126 calculated from above
-2 jet sizes for altitude adjustment

= a #124 main fuel jet size.


PILOT FUEL JET SIZE CALCULATIONS:

The formula is: +1 pilot jet size increase for every +3 main jet sizes increased.

Stock pilot fuel jet size is: #40
+ 2 additional jet sizes (since we went up +6 main fuel jet sizes before the altitude compensation was factored in):

= a #42 pilot fuel jet size.

Note that no altitude compensation is needed on the pilot fuel jet since our elevation is less than 6000' a-s-l.


------------------------------

RESULT:

A #124 Main and #42 Pilot is A GOOD STARTING POINT.

******************************************************

Note that the above calculations do NOT take into account any possible changes in the sizes of the main or pilot air jets, the main needle or main needle jet size, and thus are additional variables and opportunities for tuning excellence. These are areas which are largely unexplored by most tuners, but logically should allow for additional fine tuning or additional rage and frustration.........


Normally, changing to an aftermarket exhaust does NOT require re-jetting, (or minimal re-jetting) as almost ALL of the airflow restriction in the airflow path thru the engine (meaning: ATMOSPHERE > AIRBOX > FILTER > AIRBOX BOOTS > CARBS > INTAKE MANIFOLDS > CYLINDER HEAD PASSAGES > EXHAUST SYSTEM > BACK OUT INTO THE ATMOSPHERE) is within the intake side of this air flow path, and primarily within the stock airbox/air filter. Your stock EXHAUST system can already flow more air volume than the stock INTAKE system allows.

Thus changing only the stock EXHAUST system, with no changes to the intake side of the heads, normally makes NO DIFFERENCE IN TOTAL AIRFLOW, and "no difference in total airflow" means "no difference in TOTAL FUEL FLOW" either, and thus bigger jets are not needed.


But once you start freeing up the INTAKE side of the entire system, you will produce more system airflow, even with a stock exhaust system (because, the stock exhaust system has the capability to flow more air through it than what the stock intake system allows).

This is why re-jetting is usually needed even if you keep the stock airbox and the stock exhaust, but use a K&N low-restriction filter, or even if you drill holes in the stock airbox, or leave the filter lid off.

All such actions free up the intake side airflow restrictions; the stock exhaust will move this additional airflow, and without providing addition FUEL flow to match the increased airflow (within limits, an engine will gobble up the maximum amount of airflow that it can; an internal combustion engine is actually just a self-powered AIR PUMP) then the engine will run "lean"---meaning not enough fuel to match the amount of airflow that the engine can (and now will) gulp.

Most pod type filters allow for vastly increased airflow, and thus require fuel re-jetting, and although no one really talks much about it, probably also require AIR JET changes to match the additional fuel flow, but since no one likes to deal with two parameters at once, it becomes a "tuning nightmare".


BUT, when you read all of the common symptoms of people who use pods, you quickly come to the conclusion that it's not possible to reproduce the stock "smooth in all rpm ranges" engine response. The reality is that you SHOULD be able to match it pretty darn closely, even with the increased airflow through the system, but ONLY changing the fuel jets isn't going to accomplish that. There are also air jets in the system, and they are there for a reason, as well as needle tapers and vacuum piston responsiveness issues.


For further insights and understanding, the Holy Grail (meaning: the whole miserable, un-varnished truth of what a real chore carb tuning is going to be, written by people who actually know what they're talking about, rather than by people who are trying to sell you something) can be found at:

www.factorypro.com

and then click on the "Product Support/Technical Support" link at the top of the page, then on the "Motorcycle Tuning Tech" link, and then the "CV Carb Tuning" link........and then read, weep, study, and do....if you still dare to! HINT: if reading through it makes you think to yourself "sheesh, this sounds like an incredible amount of effort!", well, you're right! That's just some of the joys (and pitfalls) of getting to play "tuning engineer", which is what you're going to be doing. Yamaha probably has 10 of those types of guys on staff, and millions of dollars of test equipment, both physical and computer-aided, that allowed them to get the mixture settings just right---from an overall drivability AND power output standpoint----and now, since you're changing the airflow parameters thru the engine, you'll have to figure it all out "from scratch", but WITHOUT the benefit of 10 trained engineers and all that test equipment and experience.

That's why we warn you that setting up a bike for pods can be quite a bit of trial-and-error procedure. You can make the calculations according to what is shown in that guideline and then order the jets that the "formula" recommends, and that should serve as a good STARTING POINT............you may (or may not!) have to do more tuning and trial-and-erroring substitution of different jet sizes, etc. to get it performing to you satisfaction, with the recognition that you may ALWAYS end up with a situation that has some kinds of trade-offs.....lazy at the lower end but runs well at mid/upper-ranges, or runs well at the lower end but a "flat-spot" at some other rpm range, etc. Unfortunately there is no magic formula........you might want to read through the factorypro.com article that I list at the end of that section, and you will get a better understanding of what is involved to get the carbs set-up properly in a non-stock configuration.

As one of our favorite experts says about pod filters: "Get a Rubik's Cube instead.....it's less trouble and actually has an eventual solution!"




- REMOVING THE AIRBOX:

The first step on your road to hell:

http://xjbikes.com/forums/index.php?threads/21608


Hint: it's the funky background music that makes it all possible!

http://www.youtube.com/watch?v=rfcKX29lSRk&feature=email


Purchasing a replacement airbox to replace the original cut-up version (https://www.youtube.com/watch?v=48PJGVf4xqk&list=RD48PJGVf4xqk) when someone thought it was a great idea to install pod filters:

http://xjbikes.com/forums/threads/new-pool-idea.81761



- RE-INSTALLING THE CARBS:

Sometimes, it's not as easy as you'd think!

http://xjbikes.com/forums/index.php?threads/29640




- LOOK MA, NO CARBS!:

EFI to solve all of your carb woes............

http://xjbikes.com/forums/index.php?threads/10574

and

http://xjbikes.com/forums/index.php?threads/29313

and

http://users.hal-pc.org/~dhutch/




EXHAUST SYSTEM:

- EXHAUST SYSTEM OVERVIEW:

As with many other systems on these bikes, the Yamaha XJ-series of exhaust systems are a mini marvel-to-behold, well thought out and engineered......so please do keep this in mind when considering aftermarket "performance" exhaust systems.

Let's start with the headpipes: many of them are actually of a double-wall design......and inner tube (that carries that gas) and an outer tube that can stay relatively cooler and thus maintains its appearance much better and longer. Additionally, they are tuned in their internal (gas-carrying) pipe diameter to match the flow characteristics needed for their intended use.....thus, for example, even though the headpipes for an XJ650RJ Seca can physically be installed onto an XJ700 engine, the inner pipe diameters do differ, and thus the swap may cause more harm than good, as it messes up with the balance of airflow thru the engine.

Pipe diameter helps determines (among other things) both the volume of exhaust gas that can be carried away, and, equally as important, the speed at which those gases will flow thru the pipe. All other things being equal, a bigger diameter pipe --- while surely capable of flowing more gas volume, will also slow down the progress of gas thru that pipe......which, in the world of exhaust gas flow --- and its important effects on intake gas flow (how well each cylinder can be scavenged of its burnt exhaust gases and allow for a full and complete incoming fuel/air charge) --- is a mighty important consideration.

http://www.gomog.com/allmorgan/exhaustbackpressure.html

By the way......although we've touched on some of the reasons above.....in regards to "swapping" headpipes between models, our best advice is: don't. Besides the whole "gas capacity and velocity" issues discussed above, there also the issue of fit: although the headpipes between a 550 and a 750 (for example) may look the same, and may actually bolt onto the cylinders heads, both their length and their unique bend angles ---- needed to follow the frame and mate up with the exhaust collector ---- will likely be different.


Next: the collector. Although these weren't used on the XJ650 Maxim and XJ1100 models --- those bikes use a crossover pipe to perform the same function --- the collector box performs a few not-so-obvious but very important functions, and does it in a very admirable manner. First, of course, it provides a transition between the headpipes and the mufflers. Second, it keeps the decibel levels down to a reasonable volume. And finally....and very important for overall engine performance.....it provides a method of assisting that all-important "gas velocity" by providing a sufficient volume of space for "warehousing" (temporarily) the exhaust gas volume, while also providing (via its unique design) the ability to assist in providing maximal exhaust gas flow.

If you've ever looked carefully at your heavy (and probably-rusty) collector, you'll notice that it is designed ("split") in such a way so that cylinders 1 & 4 (the outer two) "share" a certain internal cavity space, while cylinders 2 & 3 "share" the rest of it. This is important because of the firing order of your engine: 1-2-4-3

If cylinders #1 and 2 --- which fire sequentially (and, thus need to exhaust their spent gases sequentially) ---- were to share the same exhaust cavity, then their (sequential) exhaust gas flows would be "spaced" too close to each other (in time) and would see vastly different back-pressures (cylinder 2, which fires after cylinder 1, would see more back-pressure than cylinder 1, which emptied itself into a, well, into an "empty" exhaust collector).

To put it another way, cylinder #2 sees a lot more back-pressure than cylinder #1, because the gas pulse from #1 doesn't have much time to exit the system before the pulse from #2 is trying to squeeze itself in the same pipe. Notice that cylinders #3 and 4 have a similar situation.

The same thought goes for the other two cylinders (# 2 and 3). Notice how even the aftermarket "dual" exhaust systems suffer from the above problem, since they are really two separate system, one system being for cylinders #1 and 2 (left side) and the other being for #3 and 4. Notice how it's the "sequential" problem.....since cylinders 1 and 2 fire (and exhaust themselves) sequentially, and since those gases vent into one common chamber, that cylinder #2 is going to see more backpressure than cylinder #1 will......and same for #3 and 4.

This un-balanced situation....with different cylinders seeing different exhaust system back-pressures......can (and does) result in different amounts of burnt gas scavenging from the differing cylinders, which is not the way to get an engine to make the most amount of power.


Aftermarket 4-into-1 systems overcome this "differential scavenging" situation by re-introducing, somewhat, a "collector".......where the fours pipes come together into a common chamber, just before the muffler. This collector allows the system to maintain some amount of equalized back-pressure (and thus burnt gas scavenging), while the particular placement of the four headpipes, as they come into the collector, allows a little bit of "pull-thru" between each cylinder, helping to reduce overall system back-pressure levels, while still maintaining a somewhat equal amount of back-pressure to each cylinder.

Or, maybe, aftermarket systems do no such thing:

http://www.motorcycleproject.com/text/exhausts2.html


Of course, the final piece of the puzzle is the mufflers, which are primarily decorative pieces....they look nice, stylish to the lines of the bike, contribute almost no back pressure to the system, and provide a nice throaty (but not too loud or droning or buzzing) sound output.

So just remember that the real heavy-lifting in the exhaust system is actually done by the headpipes and the unique, well-designed (but often overlooked) collector box.



- EXHAUSTING ISSUES....:

straight pipes: just say no:

http://xjbikes.com/forums/index.php?threads/14772



straight pipes tuning tricks ---- in case you didn't listen to the above advice:

http://www.bobhenneman.info/dragpipe.htm



stock and custom exhaust sounds, for your comparison. Note that bikes parked in a garage (or their exhaust facing a wall) will sound a bit louder than they actually are "in the wild":

XJ550:

stock exhaust:
https://www.youtube.com/watch?v=Iv3Y9LhN794

4-into-1:
https://www.youtube.com/watch?v=lsPmnpn-mhg



XJ650 (except Turbo):

stock exhaust:
https://www.youtube.com/watch?v=xG9hCSkoCj4

Emgo replacement mufflers on stock system:
https://www.youtube.com/watch?v=nJNzXzdVusI

Mac 4-into-2:
https://www.youtube.com/watch?v=ydXu7kpZmMs

Open mufflers:
https://www.youtube.com/watch?v=42PaZTxft8c
https://www.youtube.com/watch?v=PamVCd9-xZ8

Mac 4-into-1:
https://www.youtube.com/watch?v=4g6lvxoW5fo

Unknown brand 4-into-1:
https://www.youtube.com/watch?v=xXkzfQv-Cak

Supertrapp 4-into-1:
https://www.youtube.com/watch?v=hRbBFpnvIcM

Marhsall 4-into-1:
https://www.youtube.com/watch?v=JbaTFRIn2xY

Something different:
https://www.youtube.com/watch?v=LqLUo-V8fS4



XJ700:

air-cooled models stock exhaust:
https://www.youtube.com/watch?v=bFT5_aHzj70

water-cooled models stock exhaust:
https://www.youtube.com/watch?v=NVcRsBMf1wE
https://www.youtube.com/watch?v=a_c8P4_IQzA

water-cooled models 4-into-1:
https://www.youtube.com/watch?v=mBv3ZrHzjXg



XJ900:

stock exhaust:
https://www.youtube.com/watch?v=ZDrz_oQ5vGk

4-into-1 Supertrapp:
https://www.youtube.com/watch?v=nuUF9KHxsAg



XJ1100 and XS1100:

stock exhaust:
https://www.youtube.com/watch?v=Yxv1NGbpXLE
https://www.youtube.com/watch?v=udh1Qb7d1l4

4-into-1 Kerker:
https://www.youtube.com/watch?v=MjVvDO6jlIE




- EXHAUST GASKETS:

exhaust port gasket hide-and-seek.....and replacement:

http://xjbikes.com/forums/index.php?threads/29356





COOLING SYSTEM:


- TIME FOR A COOL CHANGE:

changing the coolant on your water-head engines:

http://www.xj4ever.com/maxim-x coolant flush.pdf

 

ELECTRICAL SYSTEMS:


- ELECTRICAL SYSTEM OVERVIEW:

Electrical problems can be terribly difficult to diagnose properly. Electrical and fuel-related problems manifest themselves in the same ways: hard starting, mis-firing, poor performance, back-firing, etc.

Although the electrical systems on XJ bikes are fairly durable, there are a number of known, common problem areas on these bikes, which are compounded by the fact that these bikes are 25+ years old.

The fusebox is the most critical area: the stock one may have been adequate in 1981, but it's now old, outdated, and ready for the dust-bin of history. We carry replacement ATC-style fuseboxes and in-line fuse holders which allow you to easily upgrade your original.

The generator brushes wear down over time, change their electrical characteristics as they age, and need periodic replacement. They are available as complete brushes with holder assemblies, or brushes only. By the way, in a technical sense, your bike is really equipped with an Alternator, not a Generator (as Yamaha calls it), since the output of that electrical-generating device is an alternating (AC) electrical current, which is then rectified into a direct (DC) current via---you guessed it---the rectifier section of your Regulator box......

Anyway: finally, in a general electrical system sense, the wiring harness on your bike is getting old---and like most vehicle wiring harnesses from this era, they aren't (and never were) the most robust things ever made. Corrosion, weak connectors, and other assorted issues will cause you all sorts of headaches and the agony of electrical troubleshooting nightmares if not addressed and remedied.

An exceptional write-up on the electrical system on XJ-series bikes---the good, the bad, and the ugly---can be found at:

http://web.archive.org/web/20071214...ies.com/MotorCity/Speedway/7795/xjfaqbig.html

I highly recommend that you visit that site and PRINT OUT the FAQ (you never know when a web page might disappear from the web), as it is the "Electrical Bible" for XJ owners!


And understanding the importance of (and how to measure) voltage drops in circuits will go a long way to helping you successfully diagnose and solve electrical problems on your bike:

http://www.motorcycleproject.com/text/volt_drop_test.html

and here’’s an easy-to-understand guide to how to perform a voltage-drop test:

http://www.agcoauto.com/content/news/p2_articleid/330



And finally, if you want to become much more of an expert on your electrical system, we recommend this excellent site……although it was written by/for owners of the Yamaha Vision series of bikes, all of the basic information and some of the bike-specific information is also applicable to the XJ model bikes. Easy to understand, and easy to learn from, the ideas and concepts explained here can really help you become comfortable enough to perform many diagnostics and repairs to the electrical system on your bike.

http://www.jetav8r.com/Vision/IgnitionFAQ.html#aapp


A nice consolidated "cheat sheet" covering many of the electrical components on your bike can be found at:

http://www.xjbikes.com/forums/index...te-relay-switch-sensor-and-diodes-guide.27543

and

http://www.xjbikes.com/forums/threads/how-to-test-a-relay.6809/#post-57590



And a great companion write-up on these subjects and some basic ignition system trouble-shooting guidelines can be found at:

http://xjbikes.com/forums/index.php?threads/21932



And a very good review of the issue of electrical resistance in ignition systems can be found at:

http://www.ultralightnews.com/enginetroublshooting/resistorcapsandplugs.htm

Although the above article references the ignition systems in ultra-light aircraft, the same concepts apply to all ignition systems.


And Testing 101 may be a good summary for you to review, before you rip all your hair (and wiring) out:

http://xjbikes.com/forums/index.php?threads/32483


A multi-meter is one of the mandatory tools that you must have and know how to use:

http://nadp.sws.uiuc.edu/cal/PDF/MulltimeterUse.pdf

https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter?_ga=1.238289411.262114863.1436923213

http://www.masonmonitoring.com/pdf/support/UsingMultimeter.pdf

http://www.autoshop101.com/forms/elec12.pdf




Here’s a good source of info on how to actually read a wiring schematic:

https://learn.sparkfun.com/tutorials/how-to-read-a-schemati


Another good source for wiring diagrams can be found at:

NOTE: some of these may be for non-US models.

1981-3 XJ550 Maxim WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d1a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d1b.jpg


1981-83 XJ550 Seca WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d2a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d2b.jpg


The World’s Greatest XJ550 Seca Wiring Diagram:
http://www.frankjohansson.com/stuff/xj550/XJ550ElectricalDiagram.html



1980-82 XJ650 Maxim, Midnight Maxim, and Seca WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d7a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d7b.jpg


XJ650 Euro/UK WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d6a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d6b.jpg


XJ650 Turbo WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d13.jpg


1982 XJ750J Maxim WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d10a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d10b.jpg


1982-83 XJ750 Seca WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d11a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d11b.jpg


XJ750 Police WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d12a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d12b.jpg


XJ750 UK WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d9a.jpg
and
http://members.tripod.com/dave_jack/wiringdiag/d9b.jpg


Components Key Guide for all of the above WIRING DIAGRAM
http://members.tripod.com/dave_jack/wiringdiag/d8.jpg



- THE BATTERY: IT ALL STARTS RIGHT HERE:

http://www.dansmc.com/batteries.htm



- THE BATTERY: IT CONTINUES HERE:

Brand new OEM and replacement batteries will certainly solve those slow or no-start problems, but before you buy a battery............read on to determine whether you really need a battery, or whether your situation is due to some other cause.

Of course, if you determine that your battery is ready to take that trip to the great lead-acid Heaven in the sky......or, actually, to a recycling center, such as a local auto parts store........then we have a variety of choices for your specific bike.



How do I know if my battery is good?:

Is it your battery, or your charging system, or something in-between?

The best way to know for sure is to use a multimeter (voltmeter) attached directly to your battery positive and negative terminals, and observe the following:

1) with the engine and all electrical accessories off, the battery should read a minimum of 12.8 volts DC. If not, the battery is either not fully charged, or it is bad (it is incapable of holding a full charge). Charge the battery fully and check again; if the reading is less than 12.8 volts, the battery is bad and should be replaced.

NOTE: most manuals describe checking the specific gravity of each battery cell electrolyte (fluid) as the preferred method of checking the condition of the battery. This reading should be between 1.2650 - 1.280 per cell. If a fully charged battery cannot reach these levels in all cells, then that cell is bad and the battery should be replaced.


2) If the first test above passes, leave the multimeter hooked up to the battery terminals, and press the starter button. While the starter is engaged (but before the bike starts), the battery voltage should be 9.5 volts or greater. If not, then this signals either a bad battery, very dirty or weak electrical connections, or it could be a incredibly problematic starter motor (not likely; it's probably the battery!).


3) if you run into this specific problem:

* "There were a few times when I cranked it, that it ALMOST started. It would start to fire immediately as I let off the start button. But it just wouldn't catch.

Then this is a symptom of a weak battery, due to any number of causes.......

What happens is that as the starter is being engaged, it gobbles up battery voltage. As soon as the start button is released, you now have full battery voltage available TO THE IGNITION CIRCUIT (including the pick-ups, the TCI, and especially the coils), and in that instant when you release the starter button, the coils get enough voltage to produce an adequate spark while the motor is still (by inertia) turning over. If everything is in a great state of tune, the bike will normally kick over. If not, you get the "almost fires" situation explained above, so.........

Test the battery voltage WHILE THE STARTER IS ENGAGED (a voltmeter across the + and - terminals of the battery is all that's needed). It should remain above 9.5 volts while the starter motor is engaged but without the engine running. If it drops below that level while the starter is active, then that's the "problem", and the cause of that problem must be determined and remedied (usually a sign of a bad battery, or it could be a incredibly problematic starter motor).


4) Your charging system output VOLTAGE should be checked, again at the battery terminals, while the engine is running. The measured voltage should be:

* 14.2 - 14.8 Volts at about 2,000 rpms for all non-X models, and the same voltage for "X" models, but at about 3,000 rpms. Again, you would measure these voltages at the battery terminals with your voltmeter.

NOTE: If your alternator is outputting more than 14.8 volts to the battery, your regulator-rectifier unit is bad and should be replaced. Over-charging a battery will quickly ruin it, and may cause severe damage or failure of other electrical components, such as the TCI or the computer monitor system (on bikes so equipped).


Here's your cheat sheet on all of the above:


Static Battery Voltage Test

Prior to conducting this test, make sure the battery has not been
recently charged. You must wait at least one hour after charging
your battery to conduct this test.

a) Adjust voltmeter to DC volts (20 volt range).

b) Place voltmeter leads to the battery terminals (positive to positive and negative to negative).

c) Read voltage and refer to the chart below.

State of Charge:

100% Charged with Sulfate Stop:
Using a syringe Hydrometer: 1.280
Using a Digital Voltmeter: 12.80 volts
Using a Floating-Ball Hydrometer: 5 balls floating


100% Charged:
Using a syringe Hydrometer: 1.265
Using a Digital Voltmeter: 12.60 volts
Using a Floating-Ball Hydrometer: 4 balls floating


75% Charged:
Using a syringe Hydrometer: 1.210
Using a Digital Voltmeter: 12.40 volts
Using a Floating-Ball Hydrometer: 3 balls floating


50% Charged:
Using a syringe Hydrometer: 1.160
Using a Digital Voltmeter: 12.10 volts
Using a Floating-Ball Hydrometer: 2 balls floating


25% Charged:
Using a syringe Hydrometer: 1.120
Using a Digital Voltmeter: 11.90 volts
Using a Floating-Ball Hydrometer: 1 ball floating


0% Charged:
Using a syringe Hydrometer: less than 1.100
Using a Digital Voltmeter: less than 11.80 volts
Using a Floating-Ball Hydrometer: 0 balls floating




Starting Load Test:

a) Adjust voltmeter to DC volts (20 volt range).

b) Place voltmeter leads to the battery terminals (positive to positive and negative to negative) .

c) Watch the voltmeter as you start your motorcycle, but before the engine is running.

d) If the voltage drops below 9.5 volts, the battery has very low capacity and should be replaced.




Basic System Operation Test:

To test and see if the alternator is actually getting power to it (along the brown and green wires) you verify whether a magnetic field is being created inside the rotor and stator. Be sure to use a thin feeler gauge when performing this test, since the magnetic field being created is not all that strong outside the generator cover….but it will exist if the system is performing.



or

https://www.youtube.com/watch?v=lFvrId8VjeE

Hold the extended feeler gauge blade and 1/4” away from the AC generator cover and when the key is turned on the feeler gauge should pull towards the cover. The rotor should be receiving maximum excitation when the engine is not running. You should be able to measure about 12-volts on the brown wire, and approximately 1.8-volts on the green wire. The voltage regulator controls the low side (green wire) and will raise and lower the voltage based on internal voltage sensing within the regulator.




Charging System Tests:

a) Adjust voltmeter to DC volts (20 volt range).

b) Place voltmeter leads to the battery terminals (positive to positive and negative to negative).

c) Start the engine.

d) Bring engine up to approximately 2,500 rpm's.

e) Compare the voltage reading to the specification given below:

For all XJ-series models, the maximum available charging output VOLTAGE should be as follows (all values are approximate):

* approximately 500-2000 rpms: 12.6 volts gradually increasing to 14.2 volts
* 2000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all models except XJ700-X and XJ750-X)
* 3000+ rpms: 14.2 volts up to about 14.8 volts, with a maximum of 14.8 volts (all XJ700-X and XJ750-X)


NOTE: the voltage reading must be approximately 14.0 - 14.5 volts to properly charge an AGM battery......anything less, and you will quickly kill these type batteries!

If your charging voltages are too low, suspect the alternator brushes first, then perform the alternator stator and rotor checks as described in the Alternator Section elsewhere in the catalog. Alternator brushes should be replaced whenever they are less than 11mm in overall length......the factory maintenance interval indicates that you should expect to replace these brushes every 8-10,000 miles. Factory brushes have "wear marks" (scribed lines) on the brush to indicate their wear limit; these aftermarket brushes also have the scribed wear line. Overall length of these brushes are 17.10mm, with 9mm of length from the wear bars to the contact end of the brushes:

http://www.xjbikes.com/forums/threads/im-going-crazy.66888/page-4#post-466203


If your charging voltages are too high, suspect your Regulator - Rectifier unit first, and perhaps dirty or corroded electrical terminals. The procedure for checking these is too detailed to describe here, and you should consult your service manual for additional details.


5) Check the condition of your main circuit terminals.....they should be zestfully clean and un-corroded, or you're primed for a variety of problems......not only will your circuits not be getting full power out of your battery, but to add insult to injury, your charging system may think that the battery needs more juice, and so it starts cranking out amps like there's no tomorrow. It's pretty safe to say that neither of those two occurrences qualify as a Good Thing (tm), so...........start at the beginning, and inspect and clean (and then protect, like with di-electric grease or equivalent) all the [/b] terminal connection points[/b]:

* the positive battery post connection to the positive battery cable.
* the positive battery cable connection to the starter relay (or "solenoid").
* the main harness terminal connector from the starter relay.
* the main lead from the starter relay to the starter motor (both ends).
* the "main fuse" contacts inside the fusebox.
* the battery ground cable contacts at both the engine case and at the negative battery post (poor ground are just as bad as poor positive feeds; after all, it takes two to tango, or to complete a circuit, and electricity doesn't care where the restriction occurs).



Battery and Charging System Results:

Okay, now with all of the above out of the way, you should be able to determine whether you need a new battery, or not. There's no need to waste money on a replacement battery if it's not the root cause of your problems. If your battery is good, but your charging system or electrical system isn't, then spend your time and money on fixing the root causes of the problem........such efforts will also help prevent you from murdering your otherwise good battery.

But assuming that your battery is ready to be retired, the question then becomes, which battery?----as they come in a variety of types and price ranges (and, as with most things in life, the more you spend, typically, the better quality you'll get when it comes to a "commodity" product such as a battery).


Basically, motorcycle batteries are of two basic types, the flooded cell type (sometimes called a "wet cell" or "conventional" battery) and the AGM or "absorbed glass mat" type.

Your original-style, Yuasa-brand battery was a "conventional" type, and these are now available in both their original configuration, or in a high-performance version that can output more amperage than the standard style-----and this is typically a cost-effective upgrade.


AGM batteries feature cell separators made of fiberglass mats that minimize the movement of electrolyte (acid), and prevent spillage if tipped over on their side. The acid formulation in these also typically a bit stronger compared to flooded cell batteries, which accounts for their typically higher output. AGM batteries are of the permanently sealed, "maintenance-free" design, thus never requiring the further addition of water or acid.

The charging system of many modern motorcycles that come factory-equipped with an AGM type battery uses a regulator/rectifier that outputs a slightly higher voltage than a flooded cell battery requires. Using an AGM in almost any motorcycle will usually work well, while using a flooded cell battery in a bike designed for an AGM type will often result in overcharging and quick boiling of the electrolyte solution -- it isn't long before the battery is dry and possibly ruined. Of course, all of our XJ-series bikes came originally with a conventional wet ("flooded") type battery, so replacing them with the AGM types is not a problem or issue.

AGM type batteries are also more tolerant of sitting for long periods with minimum formation of lead sulfate (sulfation) on the plates. They can usually be charged at a slightly higher rate and in general provide better performance over the long haul. However, once AGM batteries are "dead"; they're dead, and cannot usually be brought back to life (even for a short amount of time) like a conventional battery can.

Finally, be aware that while AGM batteries are sometimes incorrectly called "gel cells batteries", a true "gel cell" type of battery is quite a different animal, and is actually not recommended for motorcycle use.



Battery FAQ's:


What is a conventional (or "wet" or "flooded") battery?:

These are the standard automotive type design battery, with individual push-in or screw-in battery cell access caps, a vented design, also referred to as a "lead-acid" design, and need the periodic addition of distilled water to "top up" the fluid level.



What is a "maintenance-free" battery?:

Maintenance-free batteries do not require the addition of water after their initial fill of their water/acid electrolytic solution. It means that it is a "sealed" battery, with no filler caps. Note that while conventional "wet" batteries may be available in a sealed, maintenance-free variety, AGM batteries are always of this sealed, maintenance-fee type.



What is a "high-performance" battery?:

Due to plate design and other factors, high-performance batteries have a denser charge ability and will output more amps for a longer period of time (this is the so-called *CCA rating number that is used to describe a battery) before full discharge. Although there have been some interesting technological "enhancements" to the basic conventional battery design over the years, almost all "high-performance" (meaning, higher-capacity) batteries rely on more lead material in their plates, resulting in a physically heavier battery. More lead = more money to manufacture and transport the battery, which is why these batteries cost more.

*NOTE: CCA (Cold Cranking Amperes) is the most popular industry rating and is a measurement of the current a fully charged battery can deliver for 30 seconds and maintain a voltage of 7.2 volts (12 volt battery) at a temperature of -18*-C (0* F).



What is an AGM battery?:

AGM is an abbreviation for "absorbed glass mat". In this battery design, almost all of the battery sulphuric acid solution --- which, by the way, is typically at a higher concentration level than of what is used in conventional "wet-cell" batteries --- is absorbed into glass mat separators which are sandwiched between the lead plates. It's a totally sealed and maintenance free design. There are no discharge tubes or fillers caps, which eliminates the need to maintain water levels and offers no concern about acid leaks on valuable parts and accessories.

AGM batteries offer the following advantages over conventional batteries because:

a) their sealed, maintenance-free design means you never have to worry about checking nor maintaining their fluid levels.

b) AGM batteries, unless physically damaged, will not leak or corrode your paint and chrome.

c) they have less internal resistance which offers more cranking amperage than wet batteries.

d) their lower self-discharge rate means they can sit for extended periods of time without constant monitoring. A conventional wet battery discharges 15% a month, whereas AGM batteries discharge only 2-3% a month.

e) a longer service life be expected from an AGM battery-----the main reason conventional wet batteries fail is due to water levels that are not properly monitored and maintained. Conventional batteries are also not very heat nor vibration resistant. AGM batteries are much more heat and vibration resistant than conventional batteries, and of course are maintenance-free, all of which contribute to their longer service life.

f) however, AGM batteries are more sensitive to both undercharge and overcharge conditions than conventional wet-cell, lead-acid batteries. They must be maintained correctly, and use a quality "smart" charger that does not stray too much, or too long, into the "overcharge" range of charging.



What is a gel-cell battery?:

A type of battery that you do not want to use in your XJ-series bike!



What are the electrical specifications for an original battery?:

all XJ550 and XJ650 models:

Capacity: 12ah
Charging rate: 10 hours @ 1.2A
CCA's: 113


all XJ700, XJ750, and XJ900RK models:

Capacity: 14ah
Charging rate: 10 hours @ 1.4A
CCA's: approximately 130


XJ1100 models:
Capacity: 20ah
Charging rate: 10 hours @ 2.0A
CCA's: 260


How should a battery be maintained?:

Good battery maintenance allows you to get the maximum power and life from your battery:

a) always keep the acid level between lower and upper lines on front side of the container (for conventional type batteries that are not sealed).

b) do not let the battery remain in a discharged condition for any length of time. Discover and remedy the cause of such a condition immediately.

c) when a bike is stored for over 30 days at a time, use an automatic battery charger to maintain a proper storage charge.

d) keep the top of the battery case clean, dry, and free of dirt or moisture.

e) clean the battery terminals to prevent corrosion, and treat them to some anti-corrosion spray or coat their exposed areas with di-electric grease. Do not over-tighten the terminal cinch bolts!

f) inspect the battery vent tube regularly, ensuring that it is not bent, twisted or clogged, especially at the bottom of the tube, where it discharges towards the ground......this is the most common place where the tube will get clogged via road debris, etc.

g) protect the battery from strong impacts or shocks.


How long will my new battery live?:

Regardless of battery type or manufacture, you can expect a properly activated, and properly maintained battery (meaning it's neither overcharged nor overly or repeatedly allowed to become fully discharged) to give you 2-4 solid years of life.

Heat is the big enemy of motorcycle batteries----they'll last much longer in a cool climate than a hot one. The self-discharge rate of a battery can run as high as 3% a day in hot weather with a flooded cell battery to about 1% or less per day with an AGM type. Overcharging a battery also overheats a battery---a double whammy! Make sure your charging system is in good order to get the maximum life from your battery.

Constant, repeated complete discharges of a battery will also reduce their lifespan. There's only so many times you can "drain the well" before a battery electrically gives up the ghost.


What are some of the best ways to kill a battery?:

a) Let a discharged battery freeze. Fully discharged batteries freeze at about +25-F, or just below the freezing temperature of water. Fully charged batteries freeze at about 75-F below zero. 'Nuff said........

b) Let a battery overheat.

c) Overcharge the battery........either via the use of an incorrect (or poor quality or defective battery charger), a charging system regulator gone bad, or highly corroded (high resistance) wiring harness connections within the system.

d) "Quick-charge" the battery using an incorrect style battery charger.

e) Allow the fluid level (for wet or conventional batteries) to get too low. This exposes the plates to air, which cause the plates to "sulfate", which leads to increased electrical resistance and a drop in power output.

f) Run a battery down into deep-discharge. Each full discharge event causes sulfate build-up on the lead plates. Do this enough times.....like when your charging system isn't outputting properly........and you'll kill a battery pretty quickly.

g) On conventional batteries, do not use regular tap water to fill or re-fill the battery. Tap water contains minerals and metals that will shorten the life of a battery. Always use distilled or de-mineralized water to fill a battery.


What about my original battery fluid level sensor?:

Some original models with the "computer" dashboard monitor system (1982 XJ750 Maxim, 1981-83 XJ750 Seca, and XJ1100 models) had a low-battery-fluid warning light on the dash, triggered by a fluid-level sensor which replaced one of the battery cell screw-in caps. If the fluid level in that battery cell was too low to trigger the sensor, the circuit in the computer dash warning system would read that as a low-voltage condition and would then illuminate the warning light.

So of course, the first issue in regards to these sensors is: if the light is on, first check your fluid level!

But other issues arise: it could be that the tip of the sensor has become dirty, or encrusted with deposits, in which case even if the fluid level is fine, it will still sense a low-voltage condition. This can be remedied with a gentle cleaning of the sensor tip (steel wool, brass bristle brush, etc.).

Also, the sensor reads voltage, and without enough voltage to trigger the computer system, the light illuminates. The wire path from the sensor goes through your ignition switch and if this switch has electrically "dirty" internal contacts, then that can add enough resistance to cut the voltage signal enough to trigger the dash "low Batt" warning light or display, even though the sensor is fine and the fluid level is okay! So: remove the ignition switch, and its bottom plate, and clean the copper contacts inside the ignition switch.

Finally: a few issues arise with replacement batteries in regards to the use of sensors:

a) some batteries are designed to allow you to re-use your original sensor (we also offer a replacement sensor in case your original is missing or damaged). These conventional-style batteries will feature screw-in caps and your original sensor will screw right in place (by the way, the sensor must be installed in the 4th cell over from the negative post or it will not work correctly and may damage your dash computer!).

b) but some aftermarket batteries, even though they have screw-in caps, have a different "plate depth" internally, and even though the original sensor will screw into the cell port, the sensor tip will be too deep and contact the lead plates in the battery which will cause battery, sensor, and dash computer damage! Thus you must be careful with aftermarket batteries, and measure the depth of the cell, and if it's shorter than that of an original battery, you must use plastic spacer shims (washers) to space an original sensor "upwards" to the proper depth for such batteries, or carefully trim the sensor tip shorter so that it does not ever contact the internal plates.

c) other aftermarket batteries will have push-in rather than screw-in caps. An original sensor will not fit into these batteries unless that one cell port is "threaded" to accept the sensor. This can be best accomplished by gently screwing into the cell port a proper sized and thread steel bolt, and thus "cutting threads" of the proper size into that cell port opening. Now your original screw-in sensor can be properly installed; however, the same warnings as in issue "b" above (in regards to the depth of the cell) must be observed and remedied, if necessary. Of course, make sure that as you cut these new threads into the battery case, that any plastic "shavings" that are created by this threading process do not get into (or are removed) the battery cell.

d) some of the replacement Yuasa batteries that we offer come with a replacement sensor.......in which case, you discard (or save) your original sensor and just hook up your sensor wire lead to this new sensor.

e) some aftermarket batteries.....such as the replacement "maintenance-free" (sealed) and all AGM batteries......have no "cell caps" and thus are not going to accept a sensor, at all. This present a problem, since the lack of voltage to the dash computer makes it think that there is a battery problem, and the red warning light or display message is always on or blinking at you. Although you can "reset" this annoyance away, there are two other solutions available to you in order to disable or bypass this function:

i) on models that use a warning light, you can simply remove the bulb from your dash! No more "warning" of a low battery fluid condition (except on the LCD display screen), but no more annoying blinking light, either.

ii) on all models, you can install our HCP9982 sensor bypass wire that duplicates the function of the original sensor.



What are the best battery myths?:

a) that putting a battery on a cement floor will cause it to discharge. This may have been true a long time ago, when the battery case was made of a rubber material, which would develop hairline cracks and thus allow moisture to permeate into the case, opening up an electrical circuit which would quickly discharge a battery. Modern batteries use molded plastic cases that do not suffer from such a fate.

b) that bringing a battery inside during the winter will prolong its life. Batteries produce electricity via a chemical reaction, and the chemical reaction results in the production of sulfate deposits on the lead plates within the battery, and these sulfate deposits act as electrical insulators----thus reducing the power output and the overall life of the battery. These chemical reactions slow down dramatically with lower temperatures. As long as your battery does not freeze, the lower the temperature, the less the amount of chemical reactions taking place, thus prolonging the life of the battery!

Remember, heat is one of the things that wears out batteries, because they speed up the amount and intensity of these chemical reactions that creates the sulfate deposition on the lead plates.....and those deposits are what really "kills" the battery.

By the way, the main reason why your car or bike cranks over so slowly during winter is not due to "thicker oil" (multi-viscosity oils took care of that issue a long time ago), but because of the decreased chemical reactions (meaning less electrical output generation) within the battery due to those lower temperatures.


Can I jump-start my dead motorcycle battery from a car battery?:

Yes, BUT.................

a) you need to make sure that you are using the proper gauge jumper cables.

b) hook the jumper cables up incorrectly (+ to -) and if you're lucky, you'll just burn up your TCI unit. If you're unlucky, you'll blow up your battery, your bike, or yourself.

c) make sure that your key switch and all electrical power drains are OFF before you hook up the jumper cables.

d) the best sequence of battery connection is to hook up both jumper cables onto the dead battery first, and then connect the positive lead to the good battery, and finally the negative lead to the good battery (or a good ground on the donor battery frame, etc.).



Your quest for more battery knowledge may still remains unsatisfied; if so, a great battery tutorial can be found at:

http://www.batteryfaq.org

and

http://www.dansmc.com/batteries.htm



- THE BATTERY SENSOR: I SEE DEAD BATTERIES:

Battery sensor bypass install:

http://www.xj4ever.com/HCP14180 battery sensor bypass.pdf



- THE ROOT OF MANY EVILS: REPLACING YOUR ORIGINAL FUSEBOX:

This should be on the very top of your "to-do" list, it will save you untold hours of grief and frustration down the road (no pun intended!):

Replacement Fuseboxes:

Upgrading your electrical system couldn't be simpler with one of our aftermarket style enclosed, waterproof fuse panels.....bringing your bike a long way up to 21st century standards of electrical wiring, and helping to prevent and eliminate annoying, frustrating, and down-right dangerous electrical issues that worn out stock fuseboxes suffer from.

So, if your fusebox (or the remains of it) look anything like this:

http://www.xjbikes.com/forums/index.php?threads/photo-of-new-fusebox-install.14200/#post-121673

or this:

http://xjbikes.com/forums/index.php?threads/fuse-panel-poll-yes-no-will-wont.9277/page-2#post-87015

then it's time to solve a number of problems and potential problems, all at once!


And here is the shocking video that everyone’s talking about, showing the entire install on an XJ650 Maxim model (other models, besides the XJ100 and XS1100 models, are all basically the same procedure):




FITMENT: the stock Yamaha fusebox is very flat...less than an inch tall. These aftermarket fuseblocks are quite a bit taller, and therefore may present some challenges and the need for some creative engineering to place them properly. In some cases the small "document holder" under the seat may need to be removed. We offer the following tips:

XJ550 models (all): the stock fusebox lays on top of the "tool kit caddy", and the forward "arms" of this caddy hold both the TCI (on the right side) and the fusebox (on the left side). These aftermarket fuseboxes will not fit in the same place as the stock fusebox, as the increased height will cause interference with the bottom of the seat pan. The best fit can be obtained by carefully cutting away a portion of the left tool caddy "arm", so that the replacement fusebox can be attached to the top of the air filter housing. Careful positioning of the fusebox will allow you to remove a minimal amount of the tool caddy arm material, thus retaining the structural strength of that arm. The replacement fusebox should them be retaining to the top of the air filter box via two self-tapping screws, or proper sized bolts and nuts. Here is a good image of what it should look like when you're done:

http://xjbikes.com/forums/index.php?threads/14200


XJ650 all models (except Turbo) and all 1981-83 XJ750 models: the stock fusebox lays on top of the air cleaner box lid. The replacement fuseblock can go in the same area, but some care must be taken as to positioning to make sure that the bottom of the seat pan does not contact the top of clear cover of the fuseblock. You will have to slightly reposition the fuseblock from the original mounting holes to get everything to line up properly, and you may have to remove the small plastic "document holder" that snaps into the bottom of the seat pan to secure proper clearance. Most clearance issues on these models can be resolved with the use of our FITMENT TEMPLATE and SEAT SPACER KIT listed further below.

Here are the basic steps needed, shown on an XJ650 Maxim model; XJ650RJ Seca and XJ750 Maxim and Seca models are similar. Although this how-to uses a 4-circuit replace fusebox, our 6-circuit panel installs in the same manner:

http://xjbikes.com/forums/index.php?threads/6350


XJ650 Turbo models: the stock fusebox fits into a flat plastic holder "bar" that fits over the air cleaner box. This holder will no longer be used, and the replacement fusebox will need to be screwed directly to the top of the air cleaner box.

XJ700 and XJ750-X models: these bikes already use the push-in type fuses in a fuse panel (under the gauges) that already comes with ATC style fuses for the auxiliary circuits, and there is no need to upgrade that! Therefore these replacement 6-circuit fuseboxes are not needed on these bikes. However, they also use a 30A main fuse in a separate in-line fuse holder that uses the old glass-style fuse, and that is certainly a candidate for updating with the 30A ATC style in-line fuse holder HCP6833 listed further below.

XJ900 (and possibly XJ750RL) models: the stock fusebox sits in the "electrical components compartment" caddy under the seat. The replacement fusebox will fit in place of the original fusebox inside this caddy, but you will need to add the HCP12836 spacers to the frame tubes to space the seat pan up slightly (1/8") to prevent interference between the bottom of the seat pan and the top of the fusebox. Here's a great visual how-to:

http://xjbikes.com/forums/index.php?threads/3184


XJ1100 models: some slight modification to the battery tray will need to be done; here is a good illustration of the installment procedure on these models:

http://www.xjbikes.com/Forums/viewtopic/p=176959.html



Also available are harness WIRING EXTENSION KITS that contain all the additional color-coded wiring leads, terminals, and connectors needed to make the installation of these aftermarket fuseboxes an even simpler fix!



- THE SECRET LIFE OF STARTER MOTORS:

The secret life of starter motors is revealed here, which may assist you in visualizing what the rebuild process will involve:

http://xjbikes.com/forums/index.php?threads/45727


Checking Starter Motors:

As far as checking your starter motor, the only tests that you can do are on the commutator (the segmented "snout" of the entire armature) and the brushes, and are as follows:

a) if the surface is commutator is dirty, clean it with 800-grit or finer garnet paper or crocus cloth. Make sure that any dust generated by this process is completely removed.

b) the mica insulation on the armature.....in between each of the raised "segments"......should be:

* 0.8mm (.03") below the level of adjoining segments on XJ550, FJ600, FZ600, and YX600 starter motors.

* 0.6mm (.025") below the level of adjoining segments on all XJ650, XJ700, XJ750, and XJ900 starter motors.


If the depth of this mica insulation below the level of the segments is less than the specifications given above, you should scrape away the insulation until that depth is reached (a hacksaw blade or similar tool can be shaped to fit), or take the armature to an electrical service shop to have them undercut the mica to the appropriate depth.

c) check the raised segments for continuity between each individual segment and each and every other segments. There should be continuity.

d) check for continuity between every segment (assuming the test in "c" above has already been performed) and the shaft of the armature. There should not be any continuity.

e) check the resistance of the internal coil windings of the armature. You do this via measuring the resistance across every two adjoining segments. It should be:

* 0.012 ohms +/- 6% at 70-degrees F. for all XJ550, FJ600, FZ600, and YX600 starter motors.

* 0.014 ohms +/- 6% at 70-degrees F. for all XJ650, XJ700, XJ750, and XJ900 starter motors.


f) measure the outside diameter of the segments. The minimum acceptable diameter is 27.00mm.


If any of the above tests (c-f) fails, then the armature is bad and needs to be replaced.


g) measure the length of the brushes. The minimum acceptable length is:

* 5.00mm for all XJ550, FJ600, FZ600, and YX600 starter motors.

* 8.50mm for all XJ650, XJ700, XJ750, and XJ900 starter motors.


h) check for continuity between each brush and the brush plate. There should be continuity.

i) check for continuity between each brush and its terminal bolt. There should be continuity.

j) check the condition of the shaft end bushings or bearings in the case. If they are worn, then they needs to be replaced.

k) check the condition of the ring and planetary gears. If they are worn or chipped, then they need to be replaced.

l) the only other procedure that is mentioned in the factory manual is to check the condition of the brush springs, and you are supposed to do that by comparing them to new ones.....which is kind of hard to do! The springs should be considered serviceable if they snap the brushes firmly back into position when released from tension. The exact specification is:

* 550 +/- 50 grams (18.5 +/- 1.5 ounces) of pressure, measured via the use of a spring gauge, for all XJ550, FJ600, FZ600, and YX600 starter motors.

* 800 +/- 150 grams (28.22 +/- 5.29 ounces) of pressure, measured via the use of a spring gauge, for all XJ650, XJ700, XJ750, and XJ900 starter motors.


Also, be very careful when re-assembling a starter motor. There is an alignment notch in the brush plate that must be aligned with the case properly, as well as alignment notches on the outside of the main case to the end caps. Failure to install the brushes and brush plate in their proper orientation can cause the starter motor to not work at all, or to even spin backwards! The correct rotation of the starter motor is counter-clockwise, looking at the butt-end of the motor (as it is installed on the engine); or, clockwise if you're looking the starter drive gear dead in its eye..........

Another simple check is to rotate the external toothed gear with your hand clockwise (as viewed from gear end of the starter motor). Place a voltmeter positive lead (the red probe) on the large terminal of the starter motor (the one that the battery cable is normally attached to), and place the voltmeter negative lead (the black probe) grounded somewhere on the engine case or frame. You should see about a positive 0.3 volts (DC) being generated when you rotate the gear.


Finally, always be sure to use a premium, high-temperature grease to lubricate the internal gears and bearings, and do not attempt to clean the armature via the use of strong solvent sprays (brake cleaner, carb cleaner, etc.) as the solvents may break down the insulation on the coil windings, causing an internal short.


A great video of the entire process from start (no pun intended) to finish:



And though you may not have your own personal growler, follow these basic tips anyway while you have your starter motor apart for the rebuild:

https://www.xjbikes.com/forums/threads/tackling-starter-rebuild-this-weekend.123652


By the way, if your engine is locked up for some reason (carbs flooded and hydrolocked a cylinder, for example), it's possible that a starter motor in good shape---and backed up by a good battery---can strip out the above two gears, as seen in this very nice thread:

https://www.xjrider.com/viewtopic.php?t=6298

A starter motor that spins, without turning over the engine, is symptomatic of this type of (fortunately) rare problem.



- TESTING YOUR STARTER MOTOR CIRCUIT:

http://xjbikes.com/forums/index.php?threads/7828



- THE SECRET LIFE OF STARTER SOLENOIDS:

Here's a good overview of the diagnosis process for problems with a "no-start" condition:

http://www.xjbikes.com/forums/threads/won’t-start-1983-yamaha-xj750-maxim.118050/#post-591103

and

https://www.xjbikes.com/forums/threads/help-me-plz.125369



- REBUILDING THE STARTER MOTOR SOLENOID - RELAY:

Yikes, this seems like a lot of work! But it will make your solenoid work again!! Note that the “round” type solenoids work in the exact same manner, but the can may be held together with rivets of crimped together, making it more of challenge to get inside of it.

https://xs11.club/forum/idle-talk-forum/xs11-xj11-discussion/27495-how-to-rebuild-a-starter-solenoid



- THE SECRET LIFE AND REPAIR OF THE MAIN KEY SWITCH:

http://www.xj4ever.com/clean and lube the ignition switch.pdf

http://xjbikes.com/forums/index.php?threads/34810



- TESTING ELECTRICAL RELAYS:

http://xjbikes.com/forums/index.php?threads/6809

and

http://www.xjbikes.com/forums/threads/how-to-test-a-relay.6809/#post-57590



- YOU'LL GET A CHARGE OUT OF THIS:

CHARGING SYSTEM OVERVIEW:

The following guide to understanding your charging system was contributed by Dwayne Verhey, extreme XJ-Wizard.

There are two main types of alternator systems commonly used on motorcycles. Both types depend on a magnetic field, created by magnets in the alternator rotor, to induce an electrical voltage and current flow in a stationary coil of wires-----the alternator stator. If you ever get confused as to which is which, just remember that the rotating component is the "rotating rotor", and the spaghetti-like bundle of wires is the fixed-in-place, "stationary stator"......


The first type is the permanent-magnet rotor system (used on Virago, V-max, and FJR models, among others). In these systems, the fixed-strength magnets in the spinning rotor generate a constant-strength magnetic field, and thus excite the stator coil constantly; thus the alternator puts out 100% current at all times and the voltage regulator merely serves to shunt any excess generated current to ground. The advantage of the permanent-magnet system is a reduced amount of system complexity, but at the cost of increased heat and power losses (since the alternator system is always generating maximum output, and thus using up engine horsepower, constantly).

The XJ-series of bikes follows the more common automotive model, which employs variable-strength electro-magnets in the rotor. In these systems, the variable-strength magnets in the spinning rotor, when energized, are used to form the magnetic field which excite the stator. The voltage regulator controls the voltage output by varying the input voltage applied to the rotor's electro-magnets, and thus varies the strength of the magnetic field. If the system voltage drops, the voltage regulator increases the voltage fed into the rotor electro-magnets, thus increasing the strength of the magnetic field that the magnets produce, and therefore increasing the excitation (output) from the stator....and thus the alternator output voltage increases. This type of system is more complex, but has the advantage of using less power to operate, thus freeing up engine output for more admirable purposes.

If you lose a leg, or even a single diode, it is possible to still achieve voltage if the load is minimal, but as current requirements increase, the alternator will not be able to meet the challenge and the battery will have to take up the slack. Of course, as the battery drains, the available voltage is reduced, so the maximum rotor field voltage is reduced, so the current output is reduced, so the battery has to take up more slack, so ....

The end result is the battery discharges and the bike won't start.

If you suspect alternator issues, do the following checks, in this order:

- first check the resistance on the wires to the rotor. If resistances are out of spec, then check for dirty rotor commutator rings, corroded connections, etc.----all of these problems will reduce the available rotor field voltage.

- next, check the condition of the connectors from the stator to the rectifier (the 3 white wires). There's usually 2 connectors -- one from the alternator, often hidden behind the battery box, and the other near the regulator. Corrosion in these spots will reduce the stator's outputted current (bad corrosion will often melt the connector, as the outputted current turns into heat rather than being delivered to the battery).

- finally, using your multi-meter and following the directions in the service manual, check the function of each of the 6 diodes in the rectifier to make sure the power is being properly rectified from AC to DC.


Alternator Stator:

Checking alternator stators:

These tests should be taken while the components are at a temperature of about 70-F:

a) with the engine off and key off, measure the resistance across each pair of the three white wires (white1, white2, and white3) --- thus you take a separate measurement for white1 to white2, white1 to white3, and white2 to white3 ---- at the connector should be as follows. This test is measuring whether there is any internal short within each wire bundle.

0.50 ohms +/- 10% for all XJ550 models.

0.46 ohms +/- 10% for all XJ650, all XJ700, all XJ750, and XJ900RK models.

0.37 ohms +/- 10% for all XJ1100 models.

0.40 ohms +/- 10% for all XS1100 models.


b) with the engine off and key off, measure the continuity between each wire to ground (battery negative post or engine case, etc.). Thus white1 to ground, white2 to ground, and white3 to ground. This test is measuring whether there is any short within each wire bundle to the external world.

c) with the engine running, back-probe each of those 3 white wires at their connector to ensure voltage is being generated on each leg. NOTE: the voltage on those 3 white wires is AC, not DC, so be sure to set your voltmeter properly. AND, YOUR CHECK WILL BE BETWEEN WIRE PAIRS (white1 to white2, white2 to white3, and white1 to white3….and it doesn’t matter which one you consider wire #1 or #2 or #3 to be, as long as each wire’s output is checked)……AND NOT TO THE FRAME OR (GOD HELP YOU) TO THE BATTERY NEGATIVE. You should see some voltage (the actual amount is not meaningful, nor specified) on each test, and the voltages should be about the same on each leg.



Alternator Rotors and Field Coils:

Checking alternator rotors or field coil: the resistance across the two lead wires (usually brown and green) at the connector should be as follows. Note that worn or damaged alternator brushes can affect these readings, as can "dirty" copper commutator rings on the rotor face (where the brushes contact the rotor):

4.5 ohms +/- 10% for all XJ550 models.

4.0 ohms +/- 10% for all XJ650, all XJ700, all XJ750, XJ900RK, and XJ1100 models.

3.5 ohms +/- 10% for all XS1100 models (field coil).



NOTE: for best performance, your alternator Stator and Rotor (or, the Field Coil on XS1100 models) should be replaced at the same time.




- C'MON BABY LIGHT MY FIRE:

IGNITION SYSTEM OVERVIEW:

Before we get into the list of components within your ignition system, it may be useful to explore the basics of the ignition design used on these bikes, as this knowledge may help you to better recognize, troubleshoot, and repair performance problems with your engine that you think may be due to these components.

The ignition system actually begins at the left end of your CRANKSHAFT, since the rotational position of the crankshaft determines the position of the pistons and of the camshafts. Obviously, since the purpose of the entire ignition system is to deliver a high-voltage spark at the plugs at exactly the proper instant----meaning, as the piston approaches Top Dead Center of the compression stroke----then the ignition system must "know" what the position of the crankshaft is in order to transfer that information (via electrical signals) to the major components: the PICK-UP COILS, then onto the TCI UNIT, to the IGNITION COILS, via the PLUG WIRES and through the PLUG CAPS and finally, onto the SPARK PLUGS.

But it all begins at the crankshaft, which has a flat metal ROTOR DISC bolted onto the left side snout, and which hides under the left side, round "Oil Pump Cover" (also called a "YICS" cover on YICS-equipped engines). This spinning rotor disc has a small magnet embedded within it's outer tip, and as that outer tip rotates past the fixed magnets within the PICK-UP COILS, the interaction of magnetic fields triggers a small voltage in the pick-up coil wires that lead to the TCI UNIT.

Note that since the rotor disc is fixed in position and spins along with the crankshaft, this rotor disc "knows" the position of the crankshaft at all times. And since the pick-up coils are bolted in place, and are thus stationary, whenever the spinning rotor passes by a fixed pick-up coil, and thus triggers it to send a voltage signal to the TCI, in this way the TCI unit thus also "knows" where the crankshaft is, rotationally-speaking, and thus where the pistons are in relation to Top Dead Center and when their spark plugs need to be fired.......

Also note that since there are only two pick-up coils for your four-cylinder engine, that each pick-up coil is actually providing the "firing signal" to the TCI unit for two different cylinders. In these engines, one pick-up coil is responsible for sending the signal to the TCI that eventually leads to the spark plugs firing off for cylinders #1 and #4 at the same time, and the other pick-up coil sends the message to the TCI unit to fire off spark plugs #2 and #3, again, at the same time.

Although this may seem odd at first, the mechanical arrangement within the engine of the crank throws, and thus the rods and pistons, as well as the camshaft timing, allow this situation to proceed without a problem; in fact, when one of these "paired" cylinders (for example, #1) is approaching Top Dead Center of it compression stroke----and thus is in need of a spark from its spark plug----it's "mated" cylinder (#4) is also approaching Top Dead Center, too.........but on its exhaust stroke.......and so even though cylinder #4 gets a spark at its spark plug, there's nothing in the cylinder to combust, and thus it's a "wasted" (yet harmless) spark that occurs in cylinder #4.

Obviously, the exact same situation occurs in the mated pair of cylinders #2 and #3.

In fact, the whole system is known as the "wasted spark" system, since one of the two sparks that always occur at the same time is "wasted" on a cylinder that is on its exhaust stroke............


Anyway, to continue our journey: when a pick-up coil is energized by the passing magnetic field of the spinning rotor disc, it send an electrical impulse signal to the TCI. Therefore, the TCI unit now also "knows" the position of the crankshaft (and thus of the piston). Using other sensor information.....primarily, the rotational speed (RPM's) of the engine......the computer chip in the TCI is then responsible for calculating exactly when to send a "message" to the proper IGNITION COIL to release it's energy to the proper cylinders. And note that we said "cylinders" (plural), since just like the pick-up coils, one ignition coil also sparks two cylinders at once (part of the same "wasted spark" method discussed above).


The ignition coils use a rather small (12V) input on their primary side to product a large (20,000V +) amount of electrical energy on their discharge (spark plug wires). When the TCI unit determines that "the time is right" for a particular coil to fire, it grounds that coil, which collapses the small magnetic field inside the primary side of the coil, which thus induces a large electrical field in the secondary (plug wires) side of the coil, which then rushes to ground. This electrical energy rushes down the non-resistive PLUG WIRES, through a resistor in the SPARK PLUG CAP, and finally jumps a small gap in the spark plug electrode on it's way to ground, and thus the spark occurs that fires the air-fuel mixture (in one of the two cylinders being sparked at the same time), things go boom, power gets produced, and you're on the way down the road........

A great explanation and diagram---starting at the 4:15 mark in the video---explains all of the above in a very simplified, yet understandable detail:




By the way, the firing order for the XJ550 thru XJ900 engines is 1-2-4-3, with the two center pistons coming up while the two outer pistons are going down, and the direction of engine rotation is in the same direction as your tires rotate when moving forward.



Now, What Could Go Wrong?:

Well, remember, all of these components are basically used to transmit knowledge of where the piston is within it's four-stroke cycle, and to be able to deliver a spark at the appropriate time to each cylinder to take advantage of the compressed air-fuel mixture in the cylinder (during the compression stroke). So it sometimes help to understand these component pieces as being mainly responsible for providing this stream of precise information, and the electrical-spark making (at the spark plug gap) as merely being the natural (according to the laws of physics and electricity) end-result of all this information handling and processing.


Now, unless your crankshaft was installed backwards (an impossibility, by the way!) or the camshaft was installed improperly (or if the camshaft drive chain has skipped a tooth----not a common occurrence, at all), then we can safely ignore all of these issues. And since the spinning rotor disc used to trigger the pick-up coils is bolted firmly in place at the end of the crankshaft, it can be ignored for troubleshooting issues.


But the pick-up coils themselves can go bad over time, and even though it's rare, it can happen. No pick-up coil signal out----along their wires to the TCI unit-----means no signal into the TCI unit, and the whole system breaks down. Which means the small wires from the pick-up coils to the TCI had better not be pinched, shorted to ground, or broken internally, or the message just won't get through.

NOTE: if you are having intermittent or difficult-to-diagnose ignition system problems, it may be that the wire leads from the pick-up coils (under the left round crank-end cover) have become pinched where they exit the cover and have worn through their insulation.


Of course, if the TCI unit itself is defective, then even if it is getting a signal from the pick-up coils, it is unable or unwilling to process the signal, or the signal gets processed incorrectly, and either the signal doesn't get sent to the ignition coils at the proper time, or doesn't get sent at all.


But even if the pick-up coils and the TCI are performing flawlessly---which they usually are----if the ignition coils are not getting enough voltage input to them, or, if they are not able to multiply the small incoming voltage into a much higher output voltage (that is, after all, their main purpose in life), then we have a problem.

Worn-out ignition coils, or coils that perform poorly or get cracks in their outer cases (and thus short out when moisture enters their internal shells), are a common cause of ignition system problems.


And even if the coils are performing properly, if the spark plug wires have an internal break, or an external break, and thus prevent the coil electrical output from reaching the plugs, then nothing good is going to come from all this activity.


Of course, the spark plug Resistor Caps also play a role. They have a tiny resistor embedded within them, and the purpose of the resistor is to provide, of course, electrical resistance to the flow of electrical energy. There are a couple of reasons why some resistance is necessary-----it helps eliminate electrically-generated Radio Frequency Interference "noise" (RFI), it provides a "cushion" against instantaneous electrical energy pulses (which is really hard on small, fragile electrical components, such as the capacitors and transistors in the TCI unit), and it "slows down" the passage of the electricity through the spark plug, thus providing a sort of "electrical Viagra" to spark at the plugs, allowing the electrical discharge (and thus the spark) to last a bit longer (instead of being instantaneous), thus promoting more-better and fuller combustion of the air-fuel mixture.

In fact, outside of the RFI suppression issues, it is the control of this "spark burn time" that is really the most critical issue, especially on bikes that are jetted a bit lean to begin with........as increased electrical resistance in the secondary circuit will increase the spark firing or "burn" time, and that longer burning spark assists in the more complete combustion of harder-to-fire lean fuel mixtures.


But those resistors in the spark plug caps........or in the spark plugs themselves, for those engines that use resistor plugs........do wear out over time. And when they do, their resistance increases, which means that they provide more resistance to the flow of electricity than is needed. So that 20,000 volts of electrical energy, instead of being discharged at the spark plug gap in a rather short (10 milliseconds) amount of time, gets "spread out" over a much longer period of time, and gets reduced in voltage, too. So when plug caps or plugs "go bad", they rarely fail to the point where no spark occurs at all, it's just that the electrical output is being "spread out" over such a long period of time that the energy being created in the spark plug gap is so low that it's not enough to fire the fuel mixture completely (or at all)........and that's what leads to hard starts and poor performance (and reduced gas mileage, too).

By the way, as you may have figured out by now, a spark plug that is contaminated ("fouled") by carbon or oil deposits, or one which has too large of a gap, fail to operate properly mainly because such situation can greatly increase the electrical resistance characteristics of such a plug.........and now you know why that's not a good thing.

NOTE: some models specify a different (higher) plug cap resistance for the inner 2 cylinders vs. the outer cylinders. The probable reason for this is that the inner pair of cylinders may run a bit leaner (at least on some engines) since they run warmer, and also because the YICS system should allow the inner pair to “steal” more than the outer pair. If they’re really effectively leaner, they'll need a longer duration of a spark to ignite their charge, and of course the way to achieve that is: you guessed it, increased resistance on those inner cylinders!


A very good review of the issue of electrical resistance in ignition systems can be found at:

http://www.motorcycleproject.com/motorcycle/text/plugwiretech.html

and

http://www.ultralightnews.com/enginetroublshooting/resistorcapsandplugs.htm

Although the above article references the ignition systems in ultra-light aircraft, the same concepts apply to all ignition systems.


Okay, so that's your nickel tour, and although it's not as detailed as it could be, hopefully it's enough to get you started. A good voltmeter (also called an ohmmeter) is an invaluable friend when trying to track down ignition system problems, as you must make sure that the "information" between components is actually able to travel from Point A to Point B properly, and that the individual components are, electrically-speaking, able to process and transmit the electrical information properly.


A good companion write-up to this subject and some trouble-shooting guidelines can be found at:

http://xjbikes.com/forums/index.php?threads/21932



- IGNITION SYSTEM CHEAT SHEET:

Ignition system components resistance specifications:

The following list also covers the resistance values of the spark plugs, plug caps, the ignition pick-up coils (which are located behind the left side round crankshaft end cover)m and the ignition coils. The resistance of the pick-up coils can be checked at their connector to the TCI box by measuring the resistance between the grey and the black wire (this checks the condition of the first pick-up coil) and then between the orange and the black wire (this is the resistance of the other pick-up coil).

NOTE: "K" is abbreviation for a thousand units, so "5K" ohms = 5,000 ohms of resistance, etc.

NOTE: if measuring the resistance when the pick-coils are hot (i.e. after the engine has been running for 20 minutes or more, such that the pick-up coils are fully heat-saturated), then the resistance readings will be higher by 100 – 150 ohms than at the 70-F “cold” readings shown below.

NOTE: some models within this era could have been fitted with "noise suppression" plug caps (these caps are evidenced by a metal "shield" wrapped around the plastic cap body) and such caps may have used a higher resistance rating as opposed to their stock ratings listed below (for non "noise suppression" style caps).


XJ550 models:

Pick-up coils:
650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug




XJ650 models:

Pick-up coils:
1980-81 XJ650 Maxim and Midnight Maxim: 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
1982 XJ650RJ Seca (non-yics engines): 700 ohms +/- 20% = 560 ohms to 840 ohms acceptable range
1982-84 XJ650 Maxim: 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982 XJ650RJC Seca (yics engine): 650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range
1982-83 XJ650 Turbo: 120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug




XJ700 air-cooled models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.7 ohms +/- 10% = 2.43 ohms - 2.97 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
12K ohms +/- 20% = 9,600 ohms - 14,400 ohms acceptable range


Spark plug caps:
1985 N/NC models: 5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range
1986 S/SC models: 10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range


Spark plugs:
1985 N/NC models: 0 ohms per plug
1986 S/SC models: 5K ohms per plug




XJ700-X water-cooled models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.7 ohms +/- 10% = 2.43 ohms - 2.97 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
12K ohms +/- 20% = 9,600 ohms - 14,400 ohms acceptable range


Spark plug caps:
10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range


Spark plugs:
1985 XN/XNC models: 0 ohms per plug
1986 SX/SXC models: 5K ohms per plug




XJ750 air-cooled models:

Pick-up coils:
650 ohms +/- 20% = 520 ohms to 780 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
1981-83 models: 5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range
1984 RL models: 10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug




XJ750-X water-cooled models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.7 ohms +/- 10% = 2.43 ohms - 2.97 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
12K ohms +/- 20% = 9,600 ohms - 14,400 ohms acceptable range


Spark plug caps:
10 +/- 20% = 8,000 to 12,000 ohms per cap acceptable range

Spark plugs:
5K ohms per plug




XJ900RK, RL, N, FN, and F models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
original coils, marked CM12-20: 2.7 ohms +/- 10% = 2.43 ohms - 2.97 ohms acceptable range
replacement coils, marked CM12-09 or CM12-10: 2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
original coils, marked CM12-20: 13.2K ohms +/- 20% = = 10,560 ohms - 15,840 ohms acceptable range
replacement coils, marked CM12-09 or CM12-10: 11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
RK and RL models: 5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range
N, FN, and F models: 10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range
S and SH models: 15K +/- 20% = 12,000 to 18,000 ohms per cap acceptable range

Spark plugs:
RK and RL models: 0 ohms per plug
N, FN, and F models: 5K ohms per plug




XJ1100 models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.5 ohms +/- 10% = 2.25 ohms - 2.75 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
11K ohms +/- 20% = 8,800 ohms - 13,200 ohms acceptable range


Spark plug caps:
5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug




XS1100 models:

Pick-up coils:
720 ohms +/- 20% = 576 ohms to 864 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
1.5 ohms +/- 10% = 1.35 ohms -1.65 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
15K ohms +/- 20% = 12,000 ohms - 18,000 ohms acceptable range


Spark plug caps:
5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range

Spark plugs:
0 ohms per plug




- TESTING OF THE IGNITION PICK-UP COILS:

The resistance across each pair of lead wires (at the TCI) should be checked as shown in the following video……note that resistance valves specified in the service manual is for measurements taken at 70-F, and as the coils heat up, their resistance values will change, and the use of a hair dryer or heat gun to warm up the coils is simple way to see if values go way out of range as the coils heat up:

https://www.youtube.com/watch?v=54mNJaAleCo


Resistance values at 70-F are as follows:

120 ohms +/- 10% for all XJ650 Turbo models, XJ700 all models and XJ750-X models, XJ900RK, RL, N/FN, and F models, and XJ1100 models.

650 ohms +/- 20% for all XJ550 models, 1982-84 XJ650 Maxim, 1982 XJ650RJC Seca (Canadian, yics-engine), and all air-cooled XJ750 models..

700 ohms +/- 20% for all 1980-81 XJ650 models and 1982 XJ650RJ (non-yics engine) models.

720 ohms +/- 20% for all XS1100 models

NOTE: if measuring the resistance when the pick-up coils are hot (i.e. after the engine has been running for 20 minutes or more, such that the pick-up coils are fully heat-saturated), then the resistance readings will be higher by 100 – 150F than at the 70-F “cold” readings shown above.

NOTE: if both coils are out of specifications, suspect a pinched or shorted black ground wire, which is a shared ground for both of the pick-up coils on most models. It is very unlikely (although not impossible, especially in a case of improper jump-starting, etc.) that BOTH pick-up coils would expire at the same time!

A simple test to see if the coils are working, at all is to place a voltmeter (preferably an analog unit) across the Grey or the Orange wire to the Black wire. Energize the system and watch for voltage pulses as you rotate the reluctor past the pickup. This can be done by hand or with the starter.......we'd recommend using the hand method so that the pulses are slow enough to see. These "pulses" are what the TCI "black box" counts and interprets when "deciding" when to fire the ignition coils.


NOTE: the orange lead wire is the trigger wire for the #1/#4 ignition coils, while the grey lead wire is the trigger for the #2/#3 ignition coils.



- WHICH COIL IS WHICH?:

The -82310 part number is the left side ignition coil and is for cylinders #1/4 spark plugs. It has the solid orange (ground) wire and the red-with-white-tracer-stripe (hot) wire input leading to it.

The -82320 part number is the right side coil and is for cylinders #2/3 spark plugs. It has the solid grey (ground) wire and the red-with-white-tracer-stripe (hot) wire input leading to it.



- TESTING OF THE IGNITION COILS:

Factory Yamaha coils need to "see" a total load resistance on the secondary side (the "going-to-the-plugs" side of the coil) of around 20-30K ohms (ohms being a measure of electrical resistance). Electrical resistance depends on a number of factors: wire size, type of material, length of material, ambient temperature, etc. etc. All readings are specified at 70-F.

In any case, all factory XJ coils and wires combined---BUT WITHOUT THE CAPS OR PLUGS ATTACHED---have the following primary and secondary resistance ranges.

Forget watching any other video on u-tube, etc. about how to test dual-lead ignition coils; this is the only one that shows how to properly test both the primary circuit (from the wire harness) and the secondary circuit (the "plug wires" side of the coil).......with the spark plug caps removed. You can ignore the actual readings that he is showing....the specs for XJ bikes are shown below.....but the method that he shows for testing the secondary circuit is the correct procedure:

www.youtube.com/watch?v=I0TKybs6Rnw
(skip to 3:55 for the dual-lead coil)

or you can read all about it here:

www.xjbikes.com/forums/threads/how-to-test-ignition-coils-and-plug-caps.130696



For all XJ models except XJ700, XJ750-X, and XJ900 models:

Primary (input from TCI): 2.5 ohms +/- 10%
= 2.25 ohms - 2.75 ohms acceptable range

Secondary (output to spark plugs): 11K ohms +/- 20%
= 8,800 ohms - 13,200 ohms acceptable range


For all XJ700 and XJ750-X models:

Primary (input from TCI): 2.7 ohms +/- 10%
= 2.43 ohms - 2.97 ohms acceptable range

Secondary (output to spark plugs): 12K ohms +/- 20%
= 9,600 ohms - 14,400 ohms acceptable range


For all XJ900RK, RL, N, FN, and F models:

Primary (input from TCI): 2.7 ohms +/- 10%
= 2.43 ohms - 2.97 ohms acceptable range

Secondary (output to spark plugs): 13.2K ohms +/- 20%
= 10,560 ohms - 15,840 ohms acceptable range


For all XS1100 models:

Primary (input from TCI): 1.5 ohms +/- 10%
= 1.35 ohms -1.65 ohms acceptable range

Secondary (output to spark plugs): 15K ohms +/- 20%
= 12,000 ohms - 18,000 ohms acceptable range




- READY, AIM, FIRE :

The firing order is 1-2-4-3 for all XJ engines.



- DYNA PERFORMANCE IGNITION COIL INSTALLATION:

http://www.xj4ever.com/dyna coils install.pdf



- MR. SPARK PLUG CAP:

Original TD (Tokia-Denso) and aftermarket NGK SPARK PLUG CAPS are available in a variety of styles and configurations. All plug caps include their weatherproof upper and lower rubber end boots.

Okay, before we get going, let's quickly review a little bit about the original Yamaha COILS, PLUG WIRES, PLUG CAPS, and the SPARK PLUGS used on these bikes:

Factory ignition systems are designed to operate properly with a total system resistance on the secondary side (the "going-to-the-spark-plugs" side) of the coils of around 20-30K ohms (ohms being a measure of electrical resistance). Electrical resistance depends on a number of factors: wire size, type of material, length of material, age of material, ambient temperature, etc. etc. In any case, most factory XJ coils and wires combined---BUT WITHOUT THE CAPS OR PLUGS ATTACHED---are specified to have a resistance of around 11K ohms, +/- 20%, at 68-degrees Fahrenheit. Please see the complete list of specifications in the "COILS" section above.


Plug WIRES on factory coils are non-replaceable, at least not without a bit of surgery. Suffice it to say that if your coils measure out of specs for resistance (as described above), they're junk and should be replaced, either with another factory coil or a pair of the HCP245 Dyna aftermarket coils.

We do offer an NGK plug wire in-line splicer (HCP2789) that will allow you to cut off and remove a bad factory wire and replace it with a length of our aftermarket plug wire.


The original spark plug wire resistive CAPS---mistakenly called "boots" by some people---are the hard plastic insulators that fit onto the spark plug threaded stud, and accept the plug wire from the coil on their other end via a simple "twist-on" method------yes, the plug wire end of the cap has a metal screw that bites into and "screws" onto the end of the plug wire, penetrating the plug wire inner metal core and making a mechanical connection.

Plug caps use a small internal ceramic resistor, and the resistance of each cap should be checked with an ohmmeter on a periodic basis. Caps that are +/- 20% resistance from specified levels are considered bad, and should be replaced:




NOTE: some models within this era could have been fitted with "noise suppression" plug caps (these caps are evidenced by a metal "shield" wrapped around the plastic cap body) and such caps may have used a higher resistance rating as opposed to their stock ratings listed below (for non "noise suppression" style caps).

5K +/- 20% = 4,000 to 6,000 ohms per cap acceptable range:
all XJ650 models
1985 XJ700 air-cooled models
all 1981-84 XJ750 (except XJ750RL) models
all 1983-84 XJ900RK and RL models
all XJ1100 models
all XS1100 models

10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range:
all XJ550 models
1986 XJ700 air-cooled models
all XJ700-X water-cooled models
all XJ750-X water-cooled models
1984 XJ750RL models
all 1985-up XJ900F, N, and FN models

15K +/- 20% = 12,000 to 18,000 ohms per cap acceptable range:
all XJ900S and SH models


Spark plug "boots", typically seen on automotive engine plug wires, are usually only a protective (insulating) rubber cover........there is no internal resistor (as with plug "caps") since there is an internal direct-connection from the spark plug wire to the spark plug top terminal stud. Automotive ignition systems take care of system resistance via the spark plug itself, and the spark plug wire (which is resistive, unlike on these bikes, which use non-resistive wire), and thus do not rely on a resistive plug "cap" to regulate the resistance of the ignition secondary circuit. Yamaha chose to go with non-resistive plug wire, resistive plug caps, and (on most models) non-resistive spark plugs....thus allowing the resistive plug "cap" to handle the entire resistive load for the secondary circuit.

So don’t resist (ha-ha), go ahead and read this and become an electrical-resistance genius:

http://www.motorcycleproject.com/text/plugwiretech.html


If you would like to keep your (otherwise) good condition original plug caps, you can rebuild the ones which are marked TD-131, TD-135, and TD-140 (the TD-133 caps can be rebuilt, but we do not have the correct 5K ohm resistor to fit it, and the TD-134 caps cannot be rebuilt) by replacing the internal RESISTOR CORE, the thin resistor SPRING SEAT DISC, and cleaning the TENSION SPRING and the screw-in brass cap PLUG.

http://faq.f650.com/FAQs/Photos/ElecPhotos/PlugCapUndone.jpg

http://faq.f650.com/FAQs/Photos/ElecPhotos/PlugCapUndo.jpg


Always remember, that if you replace an original resistor with a core of lesser-value resistance, you should "make-up" the difference in electrical resistance via the use of resistor plugs.



- MR. SPARK PLUG GAP:

NOTE: you should never gap nor re-gap the high-performance Iridium spark plugs! All of the gapping information below pertains only to standard spark plugs. On Iridium plugs, always leave their gap "as-is" when they are removed from their box and for evermore!!

On all engines equipped with non-Iridium plugs, you can experiment with plug gaps to try and increase performance slightly. Typically, opening up the gap slightly improves high-load and high-rpm performance; in fact, the ability to run larger plug gaps is the [/i]real[/i] reason why you should consider using high-output ignition coils…..they have the extra voltage needed to successfully bridge larger plug gaps than the stock coils do.

http://www.motorcycleproject.com/text/high_perf_ignition_coils.html


The stock gaps are given below. One user reports better overall performance on their XJ700-X (water-cooled engine) with the gap set at .048” (rather than the stock .028”).

0.60 - 0.70mm (0.024 - 0.028")
- all XJ550 engines
- all XJ700-X and XJ750-X engines

0.70 - 0.80mm (0.028 - 0.032")
- all XJ650 engines
- all XJ700 air-cooled engines
- all XJ750 air-cooled engines
- all XJ900 engines
- all XJ1100 engines

The recommended service interval for spark plugs calls for their replacement every 7,500 miles. Spark plugs should be torqued to 14 foot-pounds on all XJ models except the water-cooled XJ700-X and XJ750-X models, which only require 12 foot-pounds of torque.



- MR. SPARKY PLUG:

Original SPARK PLUGS on all XJ-series bike were the NGK brand. Although many other brands of plugs can be cross-referenced to the originals, NGK plugs offer both value and performance that is quite satisfactory, in both the original stock performance configurations, and in replacement standard or high-performance, platinum-tipped IRIDIUM IX resistive design plugs. All non-resistor plugs have zero ohms resistance, while all resistor plugs.....those with the letter "R" in their part number.....have a resistance rating of 5K (5,000) ohms.

Although spark plugs are pretty cheap (and thus it's not to hard on the wallet to replace plugs with new ones as part of an ignition system troubleshooting routine), if you want to actually check their condition, here's how you do it:

https://www.youtube.com/watch?v=hnd7P7O_vEQ


On all engines equipped with non-Iridium plugs, you can experiment with plug gaps to try and increase performance slightly. Typically, opening up the gap slightly improves high-load and high-rpm performance; in fact, the ability to run larger plug gaps is the [/i]real[/i] reason why you should consider using high-output ignition coils…..they have the extra voltage needed to successfully bridge larger plug gaps than the stock coils do.

http://www.motorcycleproject.com/text/high_perf_ignition_coils.html


The stock gaps are given below. One user reports better overall performance on their XJ700-X (water-cooled engine) with the gap set at .048” (rather than the stock .028”).

0.60 - 0.70mm (0.024 - 0.028")
- all XJ550 engines
- all XJ700-X and XJ750-X engines

0.70 - 0.80mm (0.028 - 0.032")
- all XJ650 engines
- all XJ700 air-cooled engines
- all XJ750 air-cooled engines
- all XJ900 engines
- all XJ1100 engines

The recommended service interval for spark plugs calls for their replacement every 7,500 miles. Spark plugs should be torqued to 14 foot-pounds on all XJ models except the water-cooled XJ700-X and XJ750-X models, which only require 12 foot-pounds of torque.


Spark plug knowledge you can use:

- Reading spark plugs:

http://www.motorcycleproject.com/text/reading_plugs.html

and

http://www.wallaceracing.com/plug-reading-lm.html


- Spark plug heat ranges and plug etiquette:

http://www.motorcycleproject.com/text/spark_plug_facts.html


- Believe it or not, there’s actually quite a bit of information on the proper installation and use of spark plugs that is not generally known or appreciated. A few minutes review can prevent a world of hurt, aka Don’t Lose Your Head!:

http://www.bmwmotorcycletech.info/sparkplugs.htm



- LOOK MA, BAD (PLUG) WIRES!:


https://www.youtube.com/watch?v=vCQ06vgaq4w

and

https://www.youtube.com/watch?v=qjIrFEWQEZ0



- TESTING AND REPAIR OF THE TCI BOX:

Yamaha (thankfully!) used a TCI (which stands for Transistor Controlled Ignition) system on all XJ-series bikes to control the coils, timing, spark advance, etc. A TCI unit is an "early" version of the now-common electronic control systems that are used on virtually all modern vehicles of almost every type, and even these early versions are completely maintenance-free and very rarely cause problems...........which is a good thing, because original TCI boxes are no longer available new.

When engine performance problems develops, many people immediately suspect that the cause may be within the "black box" workings of their TCI unit, which is unlikely. The factory service manual gives "instructions" for diagnosing TCI problems, and it basically says "test every other possible cause for your problem and if no other cause for the problem exists, only then should you "suspect" TCI failure, but before you buy a replacement, first try to find a known, working TCI unit from a similar bike and plug it in on the problem bike, and see if the problem goes away............"

Well!

There are four main problems that TCI units succumb to after years of reliable service:

1) bad solder joints on some of the internal components (known as "cold solder joints") result in the component pieces coming loose from the circuit board, and thus they can no longer perform their function reliably (or at all).

2) component failure......a blown-up transistor, a burned circuit trace, etc. This situation can develop if you have a short-circuit in your electrical system, or hook up your battery or jumper cables incorrectly, etc. TCI units do not like "big blue sparks" in the electrical system (except at the spark plugs, of course!).

3) another common failure of these units occurs if the TCI is continuously grounding the ignition coil (i.e. its output driver is shorted). You can verify this situation with an ohmmeter with the following tests:

- disconnect the 2-pin plug at the ignition coil and measure from the orange or grey wire to the chassis. You should see very high resistance. This should be pretty close on both the working and non-working channels.

- if you read a few ohms of resistance or less, then the TCI is bad. A shorted driver will also make the ignition coil run very hot and may ruin the coil.

4) dirty terminal connections.....clean them with electrical contact cleaner and/or miniature wire brushes or files. NOTE: sometimes the mere act of unplugging and plugging back in the connectors to the TCI unit can resolve a “dirty connectors” issue (at least, temporarily).


Bad solder joints can be repaired by someone who is skilled at that sort of diagnosis and repair, and even individual circuit components can be replaced, but it's tough to find someone in the modern world of "pitch-and-plug" skill-sets who actually has the skill and patience to do this type of work. Yamaha gave absolutely "zero" electrical specifications for checking the condition of the TCI units, besides the afore-mentioned "check everything else first" type of diagnosis.

But you can perform a simple set of tests to determine whether your TCI unit is good or not, without having a second, known good unit to install in place of the suspect unit. Although these instructions were written for XS owners, the exact same thoughts apply to the TCI units on the XJ-series of bikes:

Whoops! Unfortunately the link to that page is dead, but here are the written instructions. It does require an analog meter, as digital multi-meters do not show the swing of the needle that is required to test it.

"Using a voltmeter set on 12VDC, connect the positive meter lead to the Orange or the Grey pick-up coil lead at the TCI. Connect the negative meter lead to the black (negative) lead at the TCI. Turn on the ignition. Voltage should come right up to about 10 - 11VDC. Crank the ignition and observe the meter. Look for a wide voltage swing during cranking. A strong swing indicates that the pickups and TCI are working OK and your trouble is between the TCI and the plugs. Possibly a bad ballast resistor (XS1100 models only) , bad coil, bad plug cap or just corroded connections. Repeat this test for both Orange and Grey coil leads."

Remember that the Red wire with the white tracer stripe should always be hot with the key on. The TCI unit grounds the gray and orange wires from the ignition coils. The ignition coils fire when the TCI interrupts the ground.

The tricky part is the TCI un-grounds the gray and orange if there is no signal from the pick-up coils for a few seconds. This is to protect the coils from overheating if the key is on and the engine isn't running. So unless you check the Red/white wire to gray (or orange) really quickly, you might get false readings or a mis-diagnosis of the true nature of the problem.


All of the XJ-series TCI units are of the "4RO" style as described in the above article.


And if the above isn't enough, if you feel the need to get medieval with your TCI unit, well, then it doesn't get much better than this:

http://www.jetav8r.com/Vision/IgnitionFAQ.html

and this:

http://xjbikes.com/forums/threads/old-yamaha-diodes.32519


And for those who just can't resist a good Resistor (or transistor), here you go:

http://xjbikes.com/forums/index.php?threads/37190

and Holy Dark Mother of Fibre, don't try this at home kids!:

http://xjbikes.com/forums/index.php?threads/38234


One of the peculiarities of the TCI is the need to have at least one ground path for each secondary coil winding when checking for spark, or the TCI could (more like will) be damaged. For that reason you should never have more than one spark plug wire disconnected at any one time while cranking, and check for spark one plug at a time by grounding the plug to the head.

In a situation where you would want all plugs out…….for example, compression testing of the engine……then it is recommended that the TCI be unplugged from the main harness before testing is undertaken.


By the way, the TCI needs a minimum of about 10VDC to operate......and while the starter will spin the engine over like mad with low voltage, the TCI falls on its face at less than 10 volts.....which can lead to all sorts of confusion when a battery low-voltage condition occurs!



- WHY WON’T IT START?

Well, in order for your engine to start and run, you’ve got to have fuel, spark, and enough engine compression.

The following article is THE authoritative testing procedure if you suspect a no-start situation is due to ignition system issue. Obviously, it assumes that:

a) you are getting fuel into the carbs (verify this by loosening one (or all of them, but one at a time!) of the carb bowl drain screws and see if some fuel leaks out. If so, you got fuel! If not, you’ll need to tackle this issue and figure out why.

b) you have good engine compression. If you’re not sure, you’ll need to perform a compression test and verify that then engine is making enough compression.

c) your battery should be fully charged:

While the starter is engaged (but before the bike starts), the battery voltage should be 9.5 volts or greater. If not, then this signals either a bad battery, very dirty or weak electrical connections, or it could be an incredibly problematic starter motor (not likely; it's probably the battery!).

A low voltage during cranking will prevent the ignition coils from getting enough voltage to charge themselves enough to deliver a good spark to the plugs.

http://www.xjbikes.com/forums/threads/how-to-ignition-troubleshooting.21932/



- OIL LEVEL SENSORS:

NOTE: when swapping engines (or oil pans/sensors) beware of these differences:

- the HCP700 (analog gauge) sensor is a N.C. (normally closed) style switch when the oil level is at a correct level, while the HCP701 (computer dash) sensor is a N.O. (normally open) switch when the oil level is at a correct level. Thus these sensors, If swapped between bikes, will not give proper signaling to their warning lights or read-outs!



- SERVICING AND REBUILDING GAUGE CLUSTERS:

NOTE: do you have a speedometer or tachometer that has a squealing or “Mexican jumping bean” needle?

This type of problem could be caused by the speedo drive hub (on the wheel), the cable, or the speedo head unit.

You can try lubricating the drive cable (remove it from the bike, hold or hang it vertically, use brake clearer to blast all the old gunk out, and then re-lubricate it with motor oil). Once the “cable” is off the bike, then the inner drive cable (the actual drive cable) can usually be slipped out of the outer plastic sheath to make cleaning easier.

While the cable is off, you can test the speedo head itself using an drill with a proper size square drive socket (which will be the same size as the speedo cable squared drive end) and operate the speedo in this manner ---- the drill should be set to run in reverse, as the cable rotates CCW as you are looking at the back of the speedo (from the front of the bike looking backwards). Note that it may be difficult to reach the speedo drive input while the gauges and/or the headlight assembly are still on the bike.

Yamaha speedometers take a 2240:60 ratio to work properly. The 2240 = 60 MPH means that the cable spinning at 2240 rpm’s will read 60MPH. So you’ll need a drill capable of that speed.

If the speedo works properly when testing it in the above manner, then the issue resides with either the speedo cable (which, if not regularly cleaned internally and re-lubricated, will fail after several years) or the drive hub at the wheel. If the problem goes away, then you can move on to further testing of the cable itself. If the problem persists, the the internal mechanism needs servicing.

You can perform the same "drill test" as described above, but with the speedo drive cable connected at the speedo head, and disconnected at the wheel hub......and the far end of the speedo cable itself chucked into the drill (at the wheel hub end) and running the test again.

If the problem goes away, then you need to service or replace the speedo drive hub. If the problem continues, then it’s probably the internal gauge mechanism that needs cleaning or lubrication. This can be a tedious task and no guarantee of success. Here’s a useful guide; although shown on an XJ550 speedo head unit, they are all very similar, although the dis-assembly procedure may differ

Gauge mechanism servicing:

Cluster teardown:

https://www.xjbikes.com/forums/threads/seca-550-instrument-cluster-teardown-with-pics.14948

https://www.xjbikes.com/forums/threads/bigfitzs-seca-550-instrument-cluster-teardown.116027

XJ750 Maxim and XJ750 Seca clusters are illustrated here:

http://www.xj4ever.com/gauge cluster breakdown.pdf

And the XJ700 style gauges are shown here:

http://www.xj4ever.com/repairing your 700 gauges.pdf


Head lubrication:

https://www.xjbikes.com/forums/threads/speedo-and-tach-dissection-with-pics.15303


NOTE: we strongly recommend that you do not remove (nor try to do so) the needle assembly from the gauge unit……it is clocked into a certain position, and removing the needle shaft almost always results in a non-operational gauge upon re-assembly.



150mph speedo retrofit:

http://www.xjbikes.com/forums/threads/bigfitzs-550r-150mph-speedo-retrofit.116028



- REPLACING GAUGE CLUSTER BULBS:

http://xjbikes.com/forums/index.php?threads/6696



- REPLACING GAUGE GLASS LENSES:

http://www.xj4ever.com/repairing your 700 gauges.pdf



- REPAIRING AND REPLACING WIRE END TERMINALS:

http://www.xj4ever.com/crimping my style.pdf



- ZESTFULLY CLEAN (NO MORE GREEN!) WIRES:

www.instructables.com/id/How-to-perfectly-clean-wires-in-minutes



- LOOK MA, MORE WIRES!:

How to properly add a wire splice:

http://advrider.com/forums/showthread.php?t=281500



- LOOK MA, LESS WIRES!:

If you are doing a custom project, and just have to do away with some electrical devices, here's some basic wiring diagrams that you can use to guide your efforts:

http://xjbikes.com/forums/index.php?threads/14822

http://i.imgur.com/m1csRY7.jpg

http://i.imgur.com/eQNlgxq.jpg



- LOOK MA, BAD (PLUG) WIRES!:


https://www.youtube.com/watch?v=vCQ06vgaq4w

and

https://www.youtube.com/watch?v=qjIrFEWQEZ0



- LOOK MA, NO TURN SIGNALS!:

OEM turn signal system FLASHER and SELF-CANCELLER RELAY. In order to design a "self-canceling" turn signal system, Yamaha chose to use a simple but very different style turn signal Flasher than what is used in almost all other vehicle applications. Of course, the unique design of this flasher unit makes it, let's say, "pricey" to say the least! However, if you want your self-canceling feature to work then you'll have to use this original flasher. NOTE: most aftermarket mechanical or solid-state flashers will not function (at all) in place of the original flasher, and even the ones that do (see below) will disable the use of the self-canceller feature from operating.

Also, if you substitute LED bulbs in your turn signals for the standard incandescent bulbs, then the stock flasher (which is mechanical) will not see enough of an electrical load to be able to flash correctly, if at all. In such a situation, the stock flasher is not defective, it is just designed to operate at a much higher voltage draw than LED lights provide, and you will need to replace the stock flasher with an aftermarket solid-state flasher. NOTE: the use of most aftermarket, solid-state flasher relays will defeat the self-canceller feature of the original system.

NOTE: All of the following information applies to all models except 1984-85 FJ600, all XJ700, and XJ750-X models.....those models use an "integrated relay" unit that combines the flasher relay and self-canceller into one device.

Identification: The FLASHER is contained in a large, rectangular black hard-plastic "box" housing, and has the following 3 wires connected to it: a solid brown wire, a brown wire with a white tracer stripe, and a yellow wire with a green tracer stripe.

The SELF-CANCELLER UNIT is a rectangular, sealed, rubber-coated box with 6 wires coming out of it into a connector: a solid tan wire, two (2) white wires with a green tracer stripe, a yellow wire with a green tracer stripe, a yellow wire with a red tracer stripe, and a white wire with a red tracer stripe.

By the way, the self-canceller operates off both time AND distance measurements to determine when it should cancel the flashers.....a minimum of 10 seconds time and 150 meters (about 400 feet) distance. BOTH criteria must be met before the canceller releases the signal flasher:


http://www.xjbikes.com/forums/threads/help-with-automatic-cancel.81440


NOTE: the signal system is designed so that it will still operate if the self-canceller module fails; of course, in such a situation, you will have to cancel the signals manually (by pushing straight “in” on the thumb lever after it has returned to the center position). To diagnose problems with your signal system, you should follow these steps:

1) unplug the self-canceller from the main harness.
2) identify the following wire on the main harness side of the plug: white with green tracer stripe wire and the solid black wire.
3) using a volt/ohm meter set on the ohms x 100 range, probe those two wires and then spin the front wheel. The ohms reading should shuttle back and forth between 0 and infinity
4) if the above is good, now identify the yellow with red tracer stripe wire. Hook one lead of your ohm meter to it, and the other to a good chassis grounding point. Now, with the flasher switch on the handlebars OFF (center position), the meter should read infinity. With the lever moved to either the left or right signal engagement position, the ohm meter should read 0 ohms.

If the signals work properly when the self-canceller is disconnected from the system, then you know that the flasher relay, the bulbs, and the handlebar switch circuit (inside the control switch on the handlebars) is okay. If the signals won't operate properly, even with the self-canceller removed from the system, then it may be a problem within your control switch itself, the flasher relay, the signal bulbs, wiring, etc. The movement of the thumb lever fully to one side, AND THEN RELEASING THE LEVER, should:

a) allow the lever to return to center, and
b) keep the turn signals ON (flashing) in whichever direction you had chosen, until either:

i) the self-canceller, if plugged in the system, cancels the flashers, or......
ii) if the self-canceller is un-plugged from the system, then the flasher will not cancel until you push "in" (or "down" depending on which model bike you have) on the lever, while the lever is in the center position.


Having to hold the lever fully over to the left or right position is an indication that the internal contacts (within the switch housing) may be wonky. There is a "two-armed" contact that can get bent, or, the slider contacts may have gotten dirty and/or the solder connections to the slider contacts have broken or become loose:

http://www.xjbikes.com/forums/threads/turn-signal-switch-question-w-photo.61051/#post-453580

and

http://www.xjbikes.com/forums/threads/electrical-challenges.53983/page-2

The first link above has a good image of the copper contact "arms" that can get bent, and will thus no longer make contact with the brass "button" contact on the bottom of the pivoting lever arm (one button contact on each side of the lever arm), while the second link has some good images of the slider assembly.

 

CLUTCH, SHIFTER, TRANSMISSION, and FINAL DRIVE:

The following two fantastic videos show how power gets from your crankshaft, thru the clutch and transmission, and onto to the rear wheel. Although the animations show a chain-driven bike transmission (much like an XJ550 or any of the XJ600 models), the same concepts apply to shaft-driven bikes. Understanding how these seemingly “voodoo” parts operate and interact with each other can help make troubleshooting and repair much simpler.

I’d suggest watching both of them, in the following order (although it may seem “backwards”) to get the best understanding:


How the shifter mechanism and transmission works (and transmits power to the rear wheel):




How the clutch works (and transmits power to the transmission)….shown on 1100 engines; again, just like all of the others work:




And here’s an few un-animated versions, to show you “the real thing”:

https://www.youtube.com/watch?v=TKkInvmWrtc


Understanding the concepts of how each system actually works and interacts with the others will go a long way to helping you prepare for all of the following:



- CLUTCH REBUILDING ISSUES:

The rebuild process for most clutches is pretty straightforward; although this thread is specific for the XJ550 models, the same basic steps and parts also apply to all the XJ550 - XJ1100 models:

http://xjbikes.com/forums/index.php?threads/29541

Please note that while the above guide is specific for the XJ550 clutches, all XJ-series bikes use the same basic procedures as above, with a few minor differences in drive plate style and design.

And here’s a good introductory video on doing a basic clutch rebuild:



Here are a couple of additional do’s-and-don’ts that we would recommend:
- always check the metal drive plates for flatness using a feeler gauge and flat piece of glass, etc.
- align the throw-out gear teeth towards the SW corner.
- always use new pressure plate spring bolts!
- perform the final torque on the spring bolts in criss-cross ("star") pattern.
- use a proper cover gasket rather than sealant!


And here’s any even better one, which overcomes all of the issues noted above:

https://www.xjbikes.com/forums/threads/refurbishing-the-clutch.122029


Clutch life depends on many variables, primarily your style of clutch operation and "enthusiasm". Typically, clutch discs need replacement every 20-40,000 miles, depending on use and abuse.


XJ550 clutches use a unique style of drive plate that are "tabbed" and not symmetrical, and thus must be installed in a particular order and method that is not illustrated or explained well (or at all, or even incorrectly) in many manuals and diagrams. The following revised diagram is what you should follow; incorrect assembly of the clutch drive plates could cause serious safety and reliability issues:

http://xjbikes.com/forums/index.php?threads/22927


XJ550 can also suffer from a strange noise, which is not uncommon and is typically (but not always) harmless:

http://xjbikes.com/forums/index.php?threads/33497

although some of it can be reduced with a simple fix:

http://www.xjbikes.com/forums/threads/clutch-rattle-fix.117514


And a couple of bonus tips:

http://xjbikes.com/forums/index.php?threads/33243



- here is the proper way to adjust the pivot shaft lever arm (what the clutch cable attaches to at the clutch cover):

http://xjbikes.com/forums/index.php?threads/44555

and

http://xjbikes.com/forums/index.php?threads/25394

and

http://xjbikes.com/forums/threads/clutch-adjustment-clutch-cable-replacement-procedure.2672/

and

http://www.xjbikes.com/forums/threads/bike-not-staring-and-shifting-gears.72992/#post-479385

and

http://xjbikes.com/forums/index.php?threads/29541

see text just below the last picture on page 1.



INTERNAL SHIFTER MECHANISM PARTS:

Inside your shifter case side cover are a variety of levers and linkages that translate the motion of the your shifter foot pedal into movements that operate the SHIFTER DRUM, which in turn operates the SHIFTER FORKS which then engage or disengage the various TRANSMISSION DRIVE GEARS. Worn or damaged RETURN SPRINGS can prevent the shifter from operating properly, and are the first thing to check if your bike will not go into gear, is "stuck" in a particular gear, or if you cannot "find neutral".

Of course, there may other issues which could cause the same problems, particularly the dreaded "disintegrating primary chain guide" issue, but it's always best to determine whether a simple problem exists first..........

Pictures of the inside of the shifter assembly can be seen at:

http://xjbikes.com/forums/index.php?threads/20246

and

http://xjbikes.com/forums/index.php?threads/28233

and here’s a nice video showing all of the various components:

https://www.youtube.com/watch?v=_-T_fnMc7sA


And here’s some even nicer videos showing all the different external and internal components (shift shafts, shift drums, shifter forks, gears, and shafts) and their interactions with each other……and, don’t feel bad if not all of it makes sense to you at first. But….once you’ve mucked around, even with just the easily accessible external components (i.e. parts that are not inside the cases)…..then these videos will give you a much better insight and understanding of what you are looking at, what its function is, and how it interacts with everything else (even the invisible internal components), and that kind of understanding can be a big help in troubleshooting most problems:

https://www.youtube.com/watch?v=7EMIdGgsQ68

https://www.youtube.com/watch?v=Xtghypx8mII

https://www.youtube.com/watch?v=h9MkzOkaHd4


Oh heck, and here’s one more, bringing the clutch assembly into the picture, too, so now you can put A, B, and C together to see how the whole transmission interacts / works from the input (the rotating crankshaft) to the output (the external drive sprocket for chain-drive bikes, or the “middle drive gear” subsection of the tranny on shaft-driven bikes, which uses a “rear differential” type arrangement (like on a car) to change rotational forces and shaft motion 90-degrees….clever, eh?:

https://www.youtube.com/watch?v=JhTf7cBeGcs



A few good write-ups on the typical problems and issues involved with these parts can be accessed at:

http://xjbikes.com/forums/threads/xj550-transmission-problem.12233

http://xjbikes.com/forums/index.php?threads/19227

http://xjbikes.com/forums/index.php?threads/48591

However, please note that the exploded diagram attachment on the 19227 page is "typical" for most XJ-series bikes, the actual mechanisms will differ slightly between different models (the diagram shown in the 3rd post is correct for the XJ650 - XJ900 models; most other models use a variation on the same theme).


NOTE: if this describes your situation:

Couldn't get her out of (whichever gear you were in when the problem occurred).

This situation can be caused either by a broken TENSION SPRING (the small linear-acting spring) or by the TORSION SPRING (the one with one straight arm and one "hooked" arm). Both of these springs are designed to keep the pawl arm properly engaged with the shifter drum "star wheel" segment. Note there is also a long SCREW which retains this star wheel to the shifter drum; if that screw is loose, it will allow the star wheel to rock back and forth or not even engage with the drum, also resulting in the same type of issue.

On early XJ550, XJ650, and XJ750 Seca engines, the original torsion spring used was somewhat weak, and was replaced by an upgraded spring on later model engines, which also required a slightly different spring collar (sleeve) to be fitted.


NOTE: if this describes your situation:

"Today, after a downshift, the shift pedal would not pop back up automatically."

This problem tends to be caused by a broken TORSION SPRING (the one with straight arms on both ends of the spring) which is supposed to center the selector shaft segment. The earlier 1980-81 XJ650 and XJ750 Seca models were especially susceptible to this problem, and an upgraded, thicker spring (which required a thinner spacer collar underneath) was introduced to the 1982-later models.


Of course, some of these issues may be due to something as simple as broken shifter mechanism but it also could be dues to worn gears (see the TRANSMISSION: section further below for details) or the dreaded "disintegrating primary chain guide" issue, but it's always best to determine whether a simple problem exists first..........


NOTE: if this describes your situation:

"Over the past couple months while shifting to any gear it has gone into ghost neutrals. Steadily getting worse. Now it will not stay in gear any gear unless rolling on the throttle. As soon as you roll off the throttle it falls out of gear.”

This problem tends to be caused by a broken TORSION SPRING (the torsion spring with one straight arm and one hook on the other end of the spring) which is supposed to put tension on the “stopper arm” on the forward shaft assembly.

http://xjbikes.com/forums/threads/xj-motor-switch-out.110242/#post-557101


NOTE: and if this describes your situation, it may have nothing to do with the shifter mechanism itself, but maybe a disintegrating primary chain guide (inside the engine case) may have lodged some debris into the shifter drum, preventing the shifter pedal from operating at all (up or downshift) on occasion, or, all the time:

Starter Clutch Primary Chain Guide:

This plastic chain guide should always be replaced when the engine is apart. Similar in design and concept to the camshaft drive chain guides, as it ages it gets hard and starts shedding small (or large) chunks of plastic into the engine, some of which invariably end up in the gear shifter drum assembly.....causing you to lose the ability to upshift or downshift into some (or all) of your gears. In fact, if you experience such a shifting problem, and remove the shifter drum and dig out hunks of plastic, this is a sure sign of impending starter primary chain guide failure (followed closely by the failure of the primary chain). Pieces of hard plastic discovered during an oil change may also point to the same problem.

A great visual of this "problem child" part can be seen on the 2nd image down on this page (visual is correct for XJ650-XJ900 engines):

http://www.xjbikes.com/forums/threads/bks-winter-restomod-project-82-xj650-seca.72850/page-7

To get a better understanding of what is happening and what will be involved in solving the issue, this excellent illustrated guide on how to temporarily solve the problem of a disintegrating chain guide (and it locking up your shifter) you can review this guide from the xjcd.org website on how to do an “emergency” fix to the problem (i.e. when you're a million miles away from home):

https://www.xjcd.org/emergency_guidectomy




And here’s some good videos showing the proper method of installing ball bearings into engine cases and onto shafts:



and






- THINGS THAT GO CLUNK IN THE NIGHT: TRANSMISSION ISSUES:

Hopefully, you're reading this section of the catalog just out of intellectual (or morbid) curiosity, and not because you have a transmission problem.....which in fact, is pretty rare with these XJ series engines (except, perhaps, on the XJ1100 models). The trannies are pretty bulletproof, and many "shifting" problems or issues are really caused by worn or improperly adjusted clutch system components, shifter mechanism issues, or shifter drum (the infamous disintegrating primary chain guide problem).

However.........that's not to say that they are infallible, especially on very high-mileage or improperly operated or maintained bikes. Indeed, bikes that jump out of gear, or that won't stay in gear or even go into gear, may be suffering from worn gear "dogs" or "slots" which, taken together, are what act to synchronize and "lock" two gears together while in operation, and thus can cause all sorts of problems when worn.......due to rapid shifting, forceful shifting, or extreme high-torque shifting events.


If you've determined that your transmission problems are caused by gear or fork issues, and feel up to the task, then we can still provide you with some of these GEARS, SHIFT FORKS, and HARDWARE that you'll need. Be aware that while you can replace some of these items with the engine still in the bike, it's a tricky proposition, at best. You really should resign yourself to the fact that the engine needs to come out, the crankcase halves need to be split, and as long as you're doing that level of surgery, you might as well do a partial or full engine rebuild at the same time.............


To add a little more confusion to the whole mix, when you have these types of problems, although they typically manifest themselves on 1st gear (won't go into it) or 2nd gear (won't go in, stay in, or jumps out of), it's not always a problem with the actual "1st Gear" or "2nd Gear" set. Because of the way that these transmissions operate, it may be that the problem is actually caused by the 4th GEAR itself, since the "slots" are on the 1st Wheel Gear and the "dogs" are on the 4th Pinion Gear.......and the interaction of those two gears is what actually puts the transmission in "1st gear".


Confused yet? We certainly hope so, it means you're paying attention! For further information, we suggest you start by watching this remarkably understandable and entertaining video. Coming to you straight from 1936, this short Chevrolet promo video “Spinning Levers” is the simplest explanation of what “gearing” actually is and how a transmission works:

https://www.youtube.com/watch?v=JOLtS4VUcvQ


With the above understanding, you can then read this extremely well-written article.....although written by and for XS1100 owners, the exact same principles and circumstance apply to all of the XJ-series transmissions:

https://xs11.club/forum/repairs/transmission-aa/5292-1st-and-2nd-gear-dremmel-fix-part-1-2-and-3


Further comprehension can be achieved by reviewing this pictorial guide about how XJ transmissions operate:

https://xs11.club/forum/repairs/transmission-aa/211-xs11-transmission-pictures-and-explanation


And here is a really great (somewhat long, but at least the chap is funny and entertaining) showing you what “dogs” and “slots” are, how they affect the operation of the gearbox, and showing you a damaged tranny gear set, explains what happened, and how/why what needs to be replaced. Eventually, you’ll have an excellent working understanding of gearbox issues, what happens and what can go wrong (and why you shouldn’t ever “power shift” or slam the tranny from first to second…..unless, of course, you actually enjoy rebuilding sequential transmissions):

https://www.youtube.com/watch?v=Zq7Fu2GXMEs


These two fantastic videos show how power gets from your crankshaft, thru the clutch and transmission, and onto to the rear wheel. Although the animations show a chain-driven bike transmission (much like an XJ550 or any of the XJ600 models), the same concepts apply to shaft-driven bikes. Understanding how these seemingly “voodoo” parts operate and interact with each other can help make troubleshooting and repair much simpler.

I’d suggest watching both of them, in the following order (although it may seem “backwards”) to get the best understanding:


How the shifter mechanism and transmission works (and transmits power to the rear wheel):

https://www.youtube.com/watch?v=g8xnIFf4id4


How the clutch works (and transmits power to the transmission)….shown on 1100 engines; again, just like all of the others work:

https://www.youtube.com/watch?v=JhTf7cBeGcs


And here’s an un-animated versions, to show you “the real thing”:

https://www.youtube.com/watch?v=TKkInvmWrtc




- DRIVE CHAINS:

XJ550, FJ600, and XJ600 models used the tried-and-true reliable chain drive system for such power transmission, while all XJ650-up models used a newly developed, smoother and more maintenance-free shaft drive system.....well, except for this one:

http://www.xjbikes.com/forums/threads/the-ultimate-chain-drive-xj-bike-that-does-exist.48461/


While certainly reliable and keeping with the traditional of Yamaha quality, drive chains by their nature will both wear, stretch, and need periodic cleaning, lubrication, maintenance, and eventual replacement of the drive chain and both drive sprockets:

http://www.motorcycleproject.com/text/chains.html


Our line of original and top-quality aftermarket items will keep your chain-gang of components in-line, doin' time, and humming right along for years to come.

As a general rule of thumb, you can expect original drive chains and sprockets to last about 10-15,000 miles, a little more or less depending on your driving style (heavy on the throttle, or trying to pull wheelies dramatically lessens the chain life) and riding conditions (wet weather or dirty/dusty conditions will also reduce chain life) and the maintenance schedule observed (no cleaning and re-oiling of the chain or periodic tension and alignment adjustments means also you'll be replacing parts fairly quickly!).

Chain technology has changed and evolved greatly since the 1980's, and chains can now be had in three basic types----and each in a mind-numbing different grades or versions----any of which can add to the durability and service life of the chain, while also being available at different price points. We've tried to take the mystery and "salesmanship" out of drive chains for you, and have pared down our selection to what we believe is the best price-to-performance ratio on the market today.

Your original chain is what is now known as a STANDARD CHAIN, and it has no additional rings or seals to help extend the life of the pins and rollers. A good basic chain such these will last about as long as an original chain, somewhere between 10,000 to 15,000 miles.

The first step upwards in "performance" chain is an O-RING CHAIN, which uses rubber o-rings to seal off the pins from the chain side plates. Since it's the PINS that stretch and wear (and not the rollers, as is commonly assumed), anything that can be done to prevent wear to the pins is a Good Thing.......and an o-ring which seals off the pin from where it enters the roller, thus keeping dirt and grit out while helping to retain lubrication in.......greatly improves the life of the chain. O-Ring style chains can generally be expected to last about 30% longer than a standard type chain, but..........with the introduction a few years ago of the X-ring style chains, there is no longer any meaningful price-to-performance difference between O-ring and X-ring style chains. Bottom line: the very small difference in price between an o-ring chain and an x-ring chain isn't worth the cost savings, in terms of the much greater strength and longevity of the x-ring style chains. Thus we do not offer any o-ring style chains!

The top-of-the-line style chain is an X-RING CHAIN, which is really an enhanced version of the o-ring type chain. X-rings are merely o-rings that feature two or more additional sealing "faces" molded into the rubber surface of the ring, thus giving more contact and thus more lubrication sealing points for the rubber ring----which means, in the case of drive chains, more dirt and grit being sealed OUT, and more lubrication "pooling" points to hold the lube IN. X-Ring style chains cost a bit more, but you can normally expect an additional 25-40% chain life over an o-ring style chain.

And once again----the life expectancy of any type of chain will be dramatically reduced by failing to lubricate often enough (once every two weeks is recommended for regularly driven bikes) or in a proper manner (clean first, then lubricate the from both sides at the bottom of the rear sprocket) or with a proper high-quality lubricant (such as the PJ1 chain lubes that we offer).

And of course, it should go without saying, but here goes anyway!: the quickest way to wear out a chain is to use it with worn or mis-aligned sprockets. You should ALWAYS replace your sprockets (both of them, front and rear) when you replace the chain. And you should follow the proper alignment, tightening, and adjustment procedures and schedules in your service manual in order to realize the maximum chain life.


Now, all of the above has to do with the LIFE EXPECTANCY OF THE CHAIN.....and nothing to do with the STRENGTH of the chain. Regardless of which style chain construction is used, chain strength is always expressed as the "tensile rating" of a chain. which is really a measure of how much shear strength the pins have. It's a measure of how much weight a chain can hold before it shears, and it's expressed as pounds of dead weight. For an XJ550 or FJ600 engine, anything above 7,000 pounds of tensile strength is more than adequate for even a high-performance, enthusiastically driven street bike.

All of the chains that we offer are pre-stressed for maximum performance, and pre-stretched for the longest life and ease of maintenance.

Finally, to replace your drive chain you will need to obtain a chain breaker and riveter tool; not cheap but a necessary evil. And although many chains are offered with either a rivet or clip type of master link, we've always found that the rivet style performs better and more reliably than a clip style, so that is what we offer whenever there is a choice of style available.

So, there you have it. We're going to start at the beginning (at the front output shaft drive sprocket) and work our way back. Enjoy the ride!


Chain wear specifications are as follows: check the amount of FREE PLAY in your chain by placing the transmission in neutral, and the bike on the centerstand. Push up on the bottom run of chain, midway in-between the front and rear sprockets. The allowable amount of free-play is 35-40mm, and if more or less is observed, the chain need adjustment (via the puller mechanism) or replacement if no further adjustment is possible. NOTE: user experience shows that setting the free-play to 40mm~45mm (instead of the factory-recommended 35-40mm slack) will allow the chain to hold its adjustment longer, with no negative effects on chain or sprocket wear.

With the bike still up on the centerstand, check for excessive chain wear by pulling the chain AWAY from the rear sprocket, at the 3-o'clock position of the sprocket. If more than 1/2 of a sprocket tooth can be uncovered, then the chain needs to be adjusted (via the puller mechanism), or replaced if adjustment limits have been reached.

A good visual representation of this procedure can be seen at:

http://xjbikes.com/forums/index.php?threads/28367

Failure to properly adjust the chain results in "fish-hooked" sprockets, adding additional expense and efforts to your maintenance:

http://www.xjbikes.com/forums/threads/advice-on-what-chain-to-use.70568/#post-473221

Please refer to a factory service or aftermarket workshop manual for further inspection, lubrication, and chain drive system maintenance procedures and techniques.


- The World's Fastest XJ, a/k/a Gear Ratio Analysis:

The original rear wheel sprocket is either a 45-tooth, alloy-steel gear (all XJ550 and all FJ600 models except the 1981 XJ550 Seca), a 46-tooth gear (1981 XJ550 Seca only), or a 48-tooth gear (all XJ600 Seca II models). Aftermarket gears are available in a variety of different tooth-count versions, and are made from a higher quality grade of steel, case hardened, hard-chromed and hand-finished for a more durable and uniform fit and function.

A rear gear with a higher tooth count than stock will give will give quicker acceleration (but may limit top speed), while a rear gear with a lower tooth count than stock results in lower engine rpm's for any given speed, and may allow a higher top speed (if the engine is powerful enough to actually achieve it at max rpm's), but will reduce acceleration.

For a quick performance comparison, here is a chart of the various combinations of drive ratios available using any combination of either a 15-, 16-, or 17-tooth front sprocket along with either a 44-, 45-, or 46-tooth rear sprocket on XJ550 and FJ600 models:

15 front and 46 rear = 3.0667-to-1 ratio (fastest acceleration)
15 front and 45 rear = 3.0000-to-1 ratio
15 front and 44 rear = 2.9333-to-1 ratio
16 front and 46 rear = 2.8750-to-1 ratio (stock 1981 XJ550 Seca)
16 front and 45 rear = 2.8125-to-1 ratio (stock 1982-3 XJ550 Seca and all XJ550 Maxims)
16 front and 44 rear = 2.7500-to-1 ratio
17 front and 46 rear = 2.7059-to-1 ratio
17 front and 45 rear = 2.6471-to-1 ratio
17 front and 44 rear = 2.5822-to-1 ratio (highest top speed)

Note that the 16/46 (2.8750 ratio) combination was stock for the 1981 XJ550 Seca only, while all other XJ550 models used the slightly "slower" 16/45 (2.8125 ratio) combination for a more overall "balanced" performance (but please note that direct comparisons of gear ratios are not the entire "story", as transmission gear ratios and wheel/tire sizes also affect the final performance, but the above figures are provided just for basic comparison purposes).

Also, XJ550 Seca owners can reduce their RPM's by about 300 rpm's (at highway speed) if you use a 4.00 x 18 rear tire (Dunlop and Avon still offer this size) instead of the stock 110/90 - 18 tire.




- DRIVE SHAFTS:

A good write-up on the driveshaft removal process and what’s involved in servicing a leaking final drive unit can be reviewed at:

http://www.xjbikes.com/forums/threads/driveshaft-removal-question.112460


Also a good video on servicing the u-joint/driveshaft/final drive system. Although this video features an XS1100 final drive, it is very similar to the type used on all of the XJ650 thru XJ1100 models:

https://www.youtube.com/watch?v=xCwMkFsKfWA



- SWINGARM BEARINGS:

Over the years, the swingarm bearings and pivot shaft parts take a beating....and when was the last time you (or anyone you know) ever lubricated them or even checked them for wear and play? Well, wear they do, and then they start moving around under load and cornering, leading to vibrations, wandering during straight-line riding, and other unnecessary, unneeded, unwanted, and undesirable (not to mention unsafe) characteristics and conditions. Wow, that a lot of "un's". Oh well.

In fact, if your bike rides "rock hard stiff" in the rear end, what you may find is not only worn-out rear shock absorbers, but easily overlooked is worn or even partially seized swingarm pivots and bearings. Since swingarm lubrication and maintenance is probably THE most overlooked aspect of preventative maintenance (do you know anyone who has ever done it?), it's a good bet that you swingarm could be silently suffering the same fate, too.....

The factory service interval for the repacking of the swingarm pivot bearings is every 10,000 miles (XJ550, XJ650, 1981-83 XJ750, and XJ1100 models) or every 16,000 miles (XJ700, XJ750-X, XJ750RL, and XJ900 models)

NOTE: the replacement of swingarm bushings (XJ550 models) or the swingarm bearings (all shaft-drive models) require proper-sized drifts to remove and install the new components, and in the case of shaft-drive swingarms, a 2- or 3-jaw bearing/bushing puller will most likely be required to remove the old races. Do not install new bearings into old races, they will wear out quickly! Here is one way to perform the race removal task on shaft-drive swingarms:

https://www.xjbikes.com/forums/threads/swing-arm-bearing-race-replacement.79492

 

SUSPENSION:


- FORK TUBE REBUILDING:

Your front suspension is called on to do a lot of different tasks, sometimes all at the same time: steering and braking are the two most critical ones that come to mind. Thus the proper operation and integrity of your front forks, and all their parts and pieces, is vital to the proper operation, handling, and safety of your bike. And worn front forks are the primary reason why your front tires wear out quickly, or in an uneven pattern.

Although your front forks are pretty simple devices....a spring, inside a fluid-filled tube, that serves to soak up road imperfections while maintaining positive-yet-smooth road feel and control....there are quite a few items that need attention and periodic replacement in order to get the proper lifetime and performance out of your system.

We offer a variety of OEM and aftermarket products and tools needed to properly maintain and service your forks and keep them firmly planted on the road beneath you.


NOTE: The process of rebuilding your forks seems mystical and difficult to many first-timers, mainly because all of the internal parts are normally hidden from view.....and thus the "fear of the unknown" takes over. The fork mechanisms on most of the XJ-series bikes are really pretty simple, and the entire process of removing your forks from the bike is more time-consuming and involved than the actual re-building procedure. HOWEVER, this is one procedure that we strongly recommend that you have a factory or aftermarket service manual at-the-ready, because there are certain diagrams, specifications, and various "tricks of the trade" that you'll want to know about and follow when doing fork surgery.

Forks on these bikes generally fall into one of two categories: simple and more-difficult. The simplest forks are the ones that are not encumbered by any additional "enhancements", such as air-assistance or anti-dive features. Here's the scorecard:


SIMPLE: XJ550 Maxim, XJ550 Seca, XJ650 Maxim and Midnight Maxim, XJ650RJ Seca, and XJ700 non-X.

SIMPLE-PLUS: due to the air-assist function, these forks have a few additional parts (mainly o-rings) that must be attended to, but again, these forks could just as easily fall under the "simple" category above: 1982-83 XJ650 Maxim, XJ650 Turbo, XJ700-X, XJ750-X, XJ750 Maxim and Midnight Maxim, and XJ1100 models.

INVOLVED: due to both their air-assist and anti-dive functions, these forks are the most difficult to work on.....mainly due to the addition of the anti-dive function, which introduces quite a few additional parts into the internal fork mechanism. You will definitely want a service manual handy while working on these forks, and pay very close attention to the order and orientation of all the small parts during dis-assembly: XJ750 Seca and XJ900RK Seca models.



The following discussion has some very good pointers, tips, and photographs that detail the fork rebuild process on a 1981 XJ650 Maxim model (one of the "simple" fork systems), and is a good point of reference to help you decide whether the task is something that you wish to attempt yourself or leave to a qualified shop. Many thanks to owner Gamuru for his excellent efforts in providing this material:

http://xjbikes.com/forums/index.php?threads/8355

and here’s a great video showing you all of the fun you’ll have doing this job the proper way:

www.youtube.com/watch?v=iO8Lv6a-2Cw



And thanks to user Tabaka45 for his expose of the XJ700 fork system with this great visual review of the procedures needed for rebuilding these forks, which can be seen at:

http://www.xjbikes.com/forums/threads/fork-seals-85-xj700n-picture-heavy.78389/



A slightly more complicated type of forking system can be found on the XJ750 Seca and XJ900RK models, due to the use of the anti-dive system. An XJ750 Seca fork system goes under the knife, here:

http://xjbikes.com/forums/index.php?threads/18730


Regular contributor Alive also has two great image-documentaries in regards to the more "complicated" fork systems. This first one shows the XJ900 (without the anti-dive system) fork rebuild process, although these images can also be used as a guide for any model front forking system that use the lower bushing on the chrome fork tubes:

http://xjbikes.com/forums/index.php?threads/4067

while this photo-journal details the secret, inner workings of the "anti-dive" units found on XJ750 Seca and XJ900RK Seca models:

http://xjbikes.com/forums/index.php?threads/1860

and

http://xjbikes.com/forums/index.php?threads/44997


and finally, for all you XJ750 Seca owners, here's the secrets to that funny and unique "oil lock valve assembly" used only on these models, and the proper orientation of all of those special washers:

http://xjbikes.com/Forums/viewtopic/p=159288.html

and

http://xjbikes.com/forums/index.php?threads/41895


1982 XJ750J Maxim owners will want to pay attention to the special guidelines in regards to properly setting the preload via correct positioning and insertion of the long damper adjusting rod unique to these forks:

http://xjbikes.com/forums/index.php?threads/32271


While many people may simply need to replace the OIL SEAL, SEAL CLIP, AND DUST BOOT (sometimes called a "DUST WIPER"), we also recommend that whenever you have your forks apart, that you also replace the upper CAP BOLT CIRCLIP or SNAP RING, the cap bolt O-RING or GASKET, the fork oil drain screw GASKET, the damper rod retaining bolt SEAL, and, on air-fork-equipped models, the AIR VALVE O-RINGS.


Replacing these items now, while the forks are apart, can help prevent leaks and problems from developing down the road.

On high-mileage bikes, you should also replace the metal slider bushings, taper spindles, and other items.


All forks usually require the use of a DAMPER ROD RETAINING TOOL to hold the damper rod in place while the lower damper rod retaining screw (in the bottom of the lower fork tube) is being loosened or tighten; otherwise, the damper rod will spin and freely and make removal and installation difficult if not impossible.

While the basic servicing and rebuilding of your forks is not a specialized skill, it can be somewhat confusing and daunting to people who have never performed such a task before. Since the procedures vary (sometimes greatly) between the different model bikes, we can give no real instructions or recommendations besides this: refer to your factory or aftermarket service manual for the proper procedures and techniques, and if you don't already have such a manual, please purchase one!

And here’s a couple of other good tips for exceptional fork rebuilding success and performance::

http://www.motorcycleproject.com/text/stiction_tuning.html

and:

http://www.motorcycleproject.com/text/shucking.html


The general layout of your forks (some models have more or less pieces than others), from the very top of the UPPER (also called the inner or chrome) TUBE moving downwards, is as follows. Note that the items underlined are the ones that we strongly recommend replacing during a fork rebuild procedure.

- Top Cap (rubber or plastic)
- Snap Ring, sometimes called a Stopper Ring
- Cap Bolt
- O-Ring for cap bolt
- Spacer (if used)
- Upper Spring Seat (if used)
- Fork Spring
- Damper Rod, with a plastic piston ring in the head
- Damper Rod Rebound Spring
- Oil Lock Valve Assembly (XJ750 Seca)

The following items may need replacing on high-mileage or neglected (dirty oil) bikes, as these items wear quickly if the fork oil was not refreshed regularly and thus was allowed to accumulate grit and abrasive particles:

- Taper Spindle
- Metal Slide Bushing #2, a split-ring bushing on the bottom of the chrome tube, not used on all models.


Air-assisted front forks (1982-3 XJ650 Maxim and Turbo, all XJ750, XJ900RK, and XJ1100 models) also included some or all of the following parts. Note that the items underlined are the ones that we strongly recommend replacing during a fork rebuild procedure.

- Schraeder Valve(s) and their protective screw-on Caps.
- O-Rings for the schraeder valve(s)
- Air joints (used on XJ650 Turbo, 1982 XJ750 Maxim, XJ900RK, and XJ1100).
- Cushion Gasket for air joint
- O-Rings internal to the air joints.
- Air Hose that connects the air joints.
- O-Rings for the end fittings of the air joint connecting hose.
- Stopper Ring on models using air joints.


Additionally, all XJ650 and XJ750 Midnight Maxim models, and XJ1100 models, had upper tube covers, their related guides and associated gaskets.


The LOWER (outer) FORK TUBE is populated as follows. Note that the items underlined are the ones that we strongly recommend replacing during a fork rebuild or seal replacement procedure.

- Dust boot
- Oil Seal Clip
- Oil seal Washer (XJ750 Seca, XJ900)
- Oil Seal
- Oil seal Spacer (XJ750 Seca, XJ1100)
- Fluid drain plug and gasket
- Damper rod retaining bolt and gasket
- Fork Oil


The following item may need replacing on high-mileage or poorly-maintained bikes:

- Metal Slide Bushing #1, a split-ring metal bushing near the top of the lower tube, just below the oil seal.




Finally, as part of any fork system service you should take the time to check the fork tube alignment.....an often over-looked part of fork system maintenance:

FORK TUBE ALIGNMENT CHECKING:

One feature of front fork systems that is typically overlooked is assuring that the two fork tubes are properly aligned with each other........that they are precisely spaced apart from each other, and also exactly aligned with each other in their "rake angles", and not "twisted" in relation to each other. Hitting large objects or deep holes with the front wheel, dropping the bike, slight bending or fatigue of the steering crown or lower bracket, or any other sort of injuries can result in fork tubes that are not perfectly in synch with each other, and that can cause both annoying and dangerous steering, handling, and braking problems.

Therefore it will be worth your while to check your fork tube alignment periodically, especially after you've had them out for a rebuild.......this will be the most time-efficient opportunity you'll have for this procedure, since it requires removal of the front wheel, headlight, and other assorted front-end components.

Although the following step-by-step guide was written for BMW owners, the same techniques and guidelines will apply on your bike:

http://w6rec.com/duane/bmw/fork/title.html


If you choose not to go through the above process, you can perform the following "poor-man's" fork alignment techniques as described in the following sections:

http://xjbikes.com/forums/index.php?threads/16145

and

http://xjbikes.com/forums/index.php?threads/9323

and

http://www.motorcycleproject.com/text/stiction_tuning.html

and

http://www.xjbikes.com/forums/threads/dropped-bike-need-help.97887/#post-533302

and a good video:





Listed in the following sections you will find our complete list of fork tube rebuild and service parts, arranged BY BIKE MODEL. The description of what each individual fork component part is, and its characteristics, is first review immediately below, and then the list of items by model follows.



UPPER (INNER) FORK TUBES AND PARTS:

Chrome Inner Fork Tubes:

ift3) Reproduction UPPER (INNER) (chrome) FORK TUBE, exactly replaces bent or rusted and pitted original tubes. Beautiful hard-chrome plating will last as long as original.

All fork tubes are precision made from centerless ground, cold-rolled steel tubing, and are then machined to proper tolerances and specifications as original. All inner tubes will fit either the left or right side. Stock length tubes are listed below. Shorter or longer length tubes are available by special order, but are non-returnable or refundable, and must be inquired about directly with us specifying the length desired.


NOTE: Used upper (inner) chrome fork tubes should always be checked for straightness using V-blocks and a run-out gauge (a local machine shop should be able to do this for your inexpensively), or using a professional quality straight-edge, or roll the tubes along a known flat surface such as a 30" x 12" wide piece of 1/4" thick plate glass (you can buy a cheap piece of scrap plate glass at Home Depot, etc.). Regardless of what anyone tells you, do NOT attempt to straighten bent tubes; they must be replaced!


Also, you should carefully inspect these chrome tubes for RUSTING or PITS in the area where the fork tube slides through the lower fork tube seal area. If there is only very minor surface rusting in this area, it may be possible to polish it out; however, if the rust has pitted or eaten into or below the surface of the metal, then you will need replace the tubes, as pitting in this area will very quickly chew up any new oil seals, and you'll have leaking seals again in no time!

http://xjbikes.com/forums/index.php?threads/42966


Inner Tube Gaiter Boots:

Although not originally used on any XJ-series bikes, these accordion-pleated thick rubber boots fit into the area between the bottom of the steering underbracket and the top of the lower (outer) fork boots, covering and protecting this area from damage, while providing an "old-school" or cafe-racer type look. They are retained to the chrome tube itself (at their top end) via spring clips, and to the top of the lower fork tube via metal screw-clamps.

For a great visual of how these boots appear when installed properly, see the images at:

http://xjbikes.com/forums/index.php?threads/16019



Inner Tube Top Cover/Cap:

The very top part of your fork tube is rubber or plastic cap, that serves to seal the chrome inner tube from dirt and moisture, as well as providing a decorative look.



Inner Fork Tube Cap Bolt Circlip, Snap Ring, or Stopper Ring:

These rings, located at the very top of the chrome legs, underneath the top Cap/Cover, are what hold all the rest of the internal goodies in. They are usually pretty corroded after years of inattention, and it is recommended that they be replaced during any fork renewal process. Be careful when removing these items, they are under spring pressure!



Inner Fork Tube Cap Bolts and Related:

This is the rather solid upper "plug" that retains the innards of the fork tube (the spring sits just below it). Some models may incorporate an o-ring onto this cap bolt; other use a gasket below it. Although these cap "bolts" normally don't wear out, their corresponding o-rings or gaskets should always be replaced. Some models with air-adjustable forks have the air valve threaded into this cap bolt, and the o-ring around that air valve should also be replaced during a fork service or rebuild. Always use a liberal coating of pure silicone grease (HCP1714) when installed these o-rings onto their cap bolts.


Cap bolts that are retained via a circlip (all XJ550 models, all XJ650 models (except Turbo), and the XJ750 Seca models) should have the circlip replaced. All other models use a threaded cap bolt that screws into the top of the fork tube, and these threads inside the fork tube should be inspected carefully and cleaned up if signs of deterioration or rust, etc. are noted.


HINT #1: the area where the CAP BOLT seals (at the top of the inner fork tubes) is very susceptible to rust from water accumulation and migration into this area. Rust and pitting in this area will not allow the upper cap bolt o-ring or gasket to seal properly.....a real problem! BE SURE TO INSPECT THIS AREA THOROUGHLY WHEN YOUR TUBES ARE APART. For proper oil and air sealing abilities (on those models equipped with air-assisted forks), you want this area to be as perfectly smooth as is possible.

If there is only surface rust, you can polish it away on fork tubes that use non-threaded cap bolts (all XJ550 models, all XJ650 models (except Turbo), and the XJ750 Seca models) using either bristle-wire brush HCP10222 or HCP10223, or our HCP9955 cylinder hone, chucked into a drill, and then follow-up with some 600- and 800-grit FINISHING PAPERS (these items are listed further below in the FORK TOOLS section).

Models using threaded fork cap bolts (XJ650 Turbo, all XJ700 models, all XJ750 models, XJ900RK, and XJ1100 models), should use the butterfly brush HCP10223, chucked into a drill,on the threaded portions and finishing paper on the smooth area above the threads.

If there are DEEP PITS in this area on the non-threaded style fork tubes, you can try polishing them out using the above method; however, if they have eaten into or below the surface of the metal, then you will either need to "rebuild" the surface (using JB Weld or some type of gel Super Glue formula to fill in the depression, and then sanding and/or honing any "high spots" back down to level).


It's always a good idea to use a strong smear of pure silicone grease (HCP1714) on the top edge of the cap bolts after they are installed; this will help to seal that area as much as possible from water migration into the fork tubes and contaminating the fork oil.



HINT #2: the surfaces where the DAMPER ROD PISTON RING seals (along the entire inner diameter of the inner fork tubes, below the top cap bolt) is also prone to rust from water absorption and accumulation in the fork oil (another great reason to change the fork oil regularly!). Rust and pitting in this area will not allow the damper rod upper plastic piston ring to seal properly.....another real problem! BE SURE TO INSPECT THIS AREA THOROUGHLY WHEN YOUR TUBES ARE APART (a strong flashlight and good eyes are needed, as it will be a "looking down the barrel of a rifle" type of view). For proper oil management abilities and thus fork function, you want this area to be as perfectly smooth as is possible.

If there is only minor surface rust, you might be able to polish it away using our HCP9255 cylinder hone with the 400-grit stones (listed further below in the FORK TOOLS section) attached to the long extension HCP10217.

If there are PITS in this area, there is no real cure for them, and the fork tube should be replaced.



Inner Tube Fork Springs:

Top-quality aftermarket progressively wound FRONT FORK COIL SPRINGS don't just "restore" the performance to your front forks, they actually improve it over the original equipment. Spring and suspension technology has come a long way in the 30 years since the XJ model bikes were designed and built, and our line of performance front coil springs will not only get rid of the sags and "mush" in your front end, but will give your bike a crisper, more controllable and predictable ride and handling quality due to their superior design, engineering, and manufacturing.

Original coil springs are what are known as "dual rate springs"........they have one fixed spring rate until a certain level of compression is reached, and then a firmer, stiffer rate (stronger resistance to compression) takes over (soft, soft, soft, soft, boom! stiff, stiff, stiff.......).

Replacement springs are what are known as a "progressive rate springs".........meaning that as the load on them increases, they get progressively firmer (softest, softest, soft, less soft, firm, firmer, firmer, really firm), rather than the "all or nothing" transition that takes places with the stock springs. Progressive rate springs tends to give both a smoother, less harsh ride, as well as increasing the performance of the front suspension during enthusiastic driving and the suspension action that it creates.


One pair of front springs does both front forks. Please note that some models will require the use, re-use, modification of the original, or the fabrication of the front spring spacers (and some models do not require the use of spacers at all).

NOTE: the more tightly coiled area of your fork springs (whether original or aftermarket) should be towards the TOP of the fork tube.



Inner Fork Tube Spring Spacers, Rebound Springs, and Spring Seats:

Used along with the coils springs, these various pieces allow for the proper pre-load and spring placement within the upper fork tube. Note that not all models used spring spacers.



Inner Tube Metal Slider Bushings:

These split-ring bushings fit over into a recess at the bottom of the inner chrome tube, and along with the lower tube slider bushing, serves as a both a tube guide and absorbs the majority of the side loading of the inner tube as it passes through the lower tube. If the fork oil hasn't been changed regularly, grit and moisture in the oil eventually wear down these slides, and thus require their replacement.



Inner Fork Tube Damper Rod:

Called a "compression cylinder" in Yamaha-engineering-speak, this precisely machined tube manages the oil flow within the fork system via oil bleed holes and passages. The top "head" of this damper rod rides within a flanged area of the upper (inner) fork tube and is also the lower spring seat for the coil spring, while the bottom of this rod is internally-threaded and bolted to the bottom end of the lower (outer) fork tube----and thus this rod is what actually makes the mechanical connection and physically "joins together" the upper and lower fork tubes.

HINT: check your the damper rod for straightness using a run-out gauge or a straightedge (or the edge of a machine-cut piece of flat glass).

The damper rod head has a plastic split-ring "piston ring" that should be inspected and replaced during a fork rebuild.



Inner Fork Tube Taper Spindle:

This oddly-named part is actually a tapered metal bushing that surrounds the lower shaft of the damper rod. If your taper spindle shows signs of wear (flat spots, gouges, scoring, etc.) then it should be replaced.




Inner Fork Tube Air System Parts:

Air Joint O-Rings:

These rubber o-rings provide and air-tight seal among the various component pieces used in air-assisted fork systems. These seals and o-rings should always be replaced during a fork rebuild procedure. And always use a generous coating of pure silicone grease (HCP1714) when installed these o-rings onto their cap bolts.



Air Inflation Valves and O-Rings:

NOTE: the top caps that are used on all of the air valves listed below are NOT the same as those used on tire valves, as the ones used on the fork air valves are much shorter.



Inner Fork Tube Retaining Hardware:

Your chrome fork tubes (properly called the "inner" fork tubes) are held to your bike via the upper and lower steering brackets. The upper bracket is called the "crown bracket" and your handlebars bolt to this bracket, while the lower bracket is called, quite logically, the under-bracket. The under-bracket has the large diameter stem that goes up through the steering neck tube (that is part of the frame), and within that tube are the steering Neck (or "Head") Bearings. This stem is then bolted to the crown bracket after it has emerged from the top side of the frame steering neck tube.

The inner fork tubes are located in round bores on both sides of the upper crown bracket and the lower under-bracket. These bore are "split" and via proper tightening of the special Cinch Bolts, the proper tension is applied to firmly locate the fork tubes to the rest of the bike.

HINTS:

a) there may be oxidation on the triple tree clamps so it might be necessary to clean the inner diameter of these upper and lower bracket clamp bores using a rotary tool with a brass wire brush wheel.

b) do NOT grease or lubricate the inner diameter of these upper and lower bracket clamp bores or put any anti-seize or other protective coatings inside these clamps, as such products will impair the effectiveness of their grip.



Crown Bracket Inner Fork Tube Retaining Hardware:

For the upper (crown) bracket, the various cinch bolts, washer, and nuts that retain the fork tube to this bracket.



Under-bracket Inner Fork Tube Retaining Hardware:

For the lower (under) bracket, the various cinch bolts, washer, and nuts that retain the fork tube to this bracket.




LOWER (OUTER) FORK TUBE PARTS:


Dust Wiper Seals:

ft1) OEM and aftermarket lower fork tube Dust Wiper Seals will stop grit and moisture from entering the lower tube cavity and chewing up the oil seals. These dust wiper seals are the things you see at the very top of the lower fork tube.



Oil Seals:

ft1) OEM and aftermarket lower fork tube Oil Seals will stop those leaks and restore the performance to your front suspension and braking system. We offer three different grades of seals to satisfy everyone's needs:

a) OEM original equipment double-lip rubber seals provide the same quality and life expectancy as the originals. Although these are not the least expensive seals, no one ever went wrong with using original manufacturer products. Oil seals come with the internal tension spring when they were originally equipped as such.

NOTE: all oil seals install with the sharp, tapered "point" of the oil seal internal wiper lips pointing "down", so that these lips can wipe the oil from the chrome tube as it exits the lower tube.

b) Standard grade aftermarket double-lip BLACK OIL SEALS are the same or better quality than the OEM seals, but normally at a better price.

c) Premium grade aftermarket seals are a significant development in fork seal technology and feature a specially designed lip and spring tensions that result in a much lower sliding friction between the seal and the fork tube. Lower friction prevents un-wanted fork movement resistance from occurring, for instance, when initially entering a corner, or braking. Ideally, you want the inner forks to move smoothly and without any "choppiness" past the lower tube seal, rather than a "starting and stopping" motion due to tube-to-seal "stiction". These seals deliver the lowest possible friction coefficient of any of our seals, and are well worth the extra cost!


HINT: the areas in the lower fork tube where the OIL SEAL and the SLIDER BUSHING are located (at the top of the lower fork tubes) should be inspected carefully after dis-assembly and seal/bushing removal for any nicks, gouges, or imperfections. For proper oil seal slider bushing seating and fitment, you want this area to be as perfectly smooth as is possible.

It is recommended that you polish these areas using some 200-, 400-, 600-, and 800-grit FINISHING PAPERS.


ALSO---it's never a bad idea to use some of the 100% Silicone Grease as an "assembly lube" when installing any of these oil seals:

HCP1714 Aftermarket o-ring and gasket installation pure SILICONE GREASE:



Although fork seals can be installed without removing the inner chrome fork tube from the lower tubes, the proper procedure is to dis-assemble the forks completely, removing the inner tube from the lower tube. Trying to remove the oil seal from the lower tube while the inner tube is still installed risks damaging the lower tube, since it is very difficult to remove the old oil seals from the lower tube while the chrome upper tube is still in place.

Here is a good video on the entire process:





Oil Seal Retaining Clips:

These C-shaped metal clips retain the lower tube Oil Seals and should be replaced along with the oil seals.



Lower Tube Metal Slider Bushings:

These split-ring bushings press into the lower tube, below the oil seal, and serves as a both a tube guide and absorbs the majority of the side loading of the inner tube as it passes through the lower tube. If the fork oil hasn't been changed regularly, grit and moisture in the oil eventually wear down these slides, which have a teflon-like coating on their inner bearing surface to eliminate resistance.



Lower Fork Tube Oil Drain Screw and Gasket:

These small phillips-head screws, near the bottom of the lower tubes, allows you to drain the tubes prior to doing an oil change, or before tube removal and dis-assembly for seal replacement or other service work. The gasket that goes behind this screw should always be replaced in order to prevent oil leaks.

HINT: this gasket has a very small, very fine recessed area around its inner diameter on one side only..........and that side fits against the bottom of the drain screw. The perfectly flat side of the gasket goes against the fork tube drain port opening.



Lower Fork Tube Damper Rod Retaining Bolt and Gasket:

These large socket-head cap screws, on the very bottom of the lower tubes, retains the inner tube damper rods to the lower tubes, and must be removed before the chrome inner tube can be separated from the lower tube for dis-assembly for seal replacement or other service work.

This screw is held in tight!----but it must be removed in order to take the fork upper and lower tubes apart in order to replace the lower tube seals, or any other internal parts.

The gasket that goes under this bolt should always be replaced in order to prevent oil leaks. These bolts, when re-installed, should be treated with a low-strength thread-locking compound.


The HCP4402 Damper Rod Retaining Tool, listed further below in the "Fork Tools" section of parts, is needed to hold the damper rod itself (to prevent it from spinning freely) while this damper rod retaining screw is loosened and removed.



Lower Fork Tube Axle Retaining Hardware:

A variety of fasteners were used to cinch the front axle shaft to the lower fork tubes. Note that models with the front axle in a leading position to the fork tubes only used one retaining bolt (on the right side lower fork tube), while models with the front axle along the lower fork tube centerline (BELOW the fork tubes) used two retaining bolts (one on each lower fork tube).




- FORK OIL:

Unlike motor oil or gear oil, fork oil's major purpose is not lubrication.....rather, it acts as part of the suspension system, providing both damping and rebound control functions. The different "weight" or viscosity of fork oils allows you to modify the ride and handling characteristics of your bike in a fairly simple way.

And yes, it IS a lubricant also!

Although many people----including, unbelievably, Yamaha itself----recommends the use of engine motor oil as a substitute for fork oil, this is not a very good idea. Engine oils (or any multi-viscosity oil) uses additives and detergents that, while wonderful in for their intended purposes inside an engine block, tranny case, or rear drive unit, are not such a good idea inside forks. Forks operate at a much lower temperature and temperature RANGE than engine and drivetrains do, and thus do not need all those additives. And fork oil also tends to contain higher percentages of molybdenum disulfide and anti-foaming agents than engine or gear oil, both of which are very important to proper fork operation.

As a small example.......most motor oils are of a multi-viscosity nature (such as 10W30) which change their viscosity in relation to their temperature (thin when cool, thicker as they warm). A very necessary and useful feature for an engine, where you do not want your oil thinning out as the engine warms up. Not such a good idea for your suspension----unless for some reason you WANT your handling characteristics to change (get stiffer) as the forks heat up!


Proper fork oil levels and scheduled change intervals are important for fork performance and fork part longevity.....water contamination, as well as particulate wear will accumulate in fork oil, and since there is no oil filtering mechanism within your forks, the only way to get the grit and gunk out (before it chews up your oil seals and slider bearings!) is to change your fork fluid regularly. Yamaha recommends a fork fluid change every 10,000 miles or 24 months (all models except 700's), or every 16,000 miles or 24 months (all 700's). If you just bought a used bike, we recommend you do a fluid change as soon as possible, because just like other routine maintenance tasks (besides engine oil changes), this is one that has very likely been ignored for the last 10-12 years!


Fork oil capacities and recommended weights are as follows. The amounts listed are per fork tube:


XJ550 Maxim: 272cc or 9.20 fluid ounces. 10W fork oil.

XJ550 Seca: 230cc or 7.78 fluid ounces. 10W fork oil.

1980-81 XJ650 Maxim and Midnight Maxim: 262cc or 8.86 fluid ounces. 10W fork oil.

1982-84 XJ650 Maxim: 278cc or 9.40 fluid ounces. 10W fork oil.

1982 XJ650RJ Seca: 236cc or 7.98 fluid ounces. 10W fork oil. Fork oil level is specified as 400mm (15.75") below the top of the tube without the spring installed, forks fully collapsed.

1982 XJ650LJ Turbo: 238cc or 8.04 fluid ounces. 10W fork oil. Fork oil level is specified as 180mm (7.09") below the top of the tube without the spring installed, forks fully collapsed.

1983 XJ650LK Turbo: unknown.

1985-86 XJ700 non-X: 383cc or 12.96 fluid ounces. 10W fork oil.

1985-86 XJ700-X: 389cc or 13.16 fluid ounces. 10W fork oil.

1982 XJ750 Maxim: 257cc or 8.69 fluid ounces. 10W fork oil.

1983 XJ750 Maxim and Midnight Maxim: 257cc or 8.69 fluid ounces. 10W fork oil. NOTE: owner's manual states that the fork oil capacity is 278cc (9.40 fluid ounces). It is unknown which measurement is correct.

1981-83 XJ750 Seca: 309cc or 10.45 fluid ounces. 20W fork oil.

1983 XJ750 E-II Seca or 1984 XJ750RL Seca: 286cc or 9.67 fluid ounces. 5W fork oil. Fork oil level is specified as 168mm (6.61") below the top of the tube without the spring installed, forks fully collapsed.

1983 XJ900RK Seca: 286cc or 9.67 fluid ounces. 5W fork oil. Fork oil level is specified as 164mm (6.46") below the top of the tube without the spring installed, forks fully collapsed.

1982-84 XJ1100 Maxim and Midnight Maxim: 210cc or 7.10 fluid ounces. 10W fork oil. Fork oil level is specified as 210mm (8.27") below the top of the tube without the spring installed, forks fully collapsed.


IMPORTANT NOTE: the above fork oil VOLUMES are for use only when using the stock fork springs. The use of aftermarket performance front fork coil springs will change those volumes, since aftermarket springs are thicker than stock----and thus displace more oil. Using the stock oil fluid VOLUME with aftermarket fork springs is a sure way to OVERFILL your forks, with the very real possibility of blowing out fork seals.


Unlike with your engine oil, where a bit too much or too little oil volume in the crankcase is not really a significant concern, with fork oil, too much or too little can cause real problems (too much oil can result in blown oil seals and a stiff, harsh ride, while too little oil volume results in excessive foaming, a soft mushy ride with possible bottoming, and erratic fork performance and lots of front end "dive" upon braking).

A better way to determine the amount of fork oil that is needed and necessary is via the measurement of the fork oil LEVEL within the tubes.....sort of like measuring the oil level with a dipstick. Yamaha does not specify this level for all models; and in any case, if using aftermarket springs, the factory oil level recommendation is not always useful. The maximum oil level should be 5-1/2" (140mm) below the top of the inner fork tube, measured with all internal fork tube components installed EXCEPT FOR THE SPRINGS, and with the inner fork tube fully collapsed into the lower (outer) tube.

In order to be as accurate as possible, we recommend the use of a suitable measuring device, such as the HCP1728 oil level syringe listed further below.

And finally, the fork oil viscosity can be changed from the factory recommendations to give a softer or firmer ride.......the lower the viscosity, the thinner the oil, and the softer the ride (i.e. 5W oil is thinner than 10W which is thinner than 20W, etc.) In this regard, you would certainly be correct in thinking of fork oil as a suspension "tuning tool"! Note that a thicker oil viscosity will have much more effect on the fork "rebound" characteristics than it will on the fork compression dampening function.

A great primer on "tuning" your forks via adjusting the oil levels can be seen at:

http://www.thumpertalk.com/forum/archive/index.php/t-89918.html

or you can fire up your supercomputer and do the calculations yourself:

http://www.peterverdone.com/archive/lowspeed.htm




- SHOCK ABSORBERS:

Stock fluid- or gas-filled, spring-assisted shock absorbers are good for about 10,000 to 20,000 miles of typical use before they are ready for that large XJ graveyard in the sky.

Of course, if you want to go thru the effort, the stock XJ650 Turbo and XJ1100 air shocks can be rebuilt, here's how:

https://xs11.club/forum/idle-talk-forum/xs11-xj11-discussion/13783-xj1100-rear-shock-rebuild




- STEERING HEAD BEARINGS EVALUATION:

Is this you?:

- "Basically, I am getting a nasty death-wobble at speed on my bike. How can I tell if the steering head bearings are bad? Head shake?"


Here's how to check your steering head bearings:

a) Place the bike on the centerstand, and have a helper sit on the rear of the seat to put the front wheel in the air.

b) Crouch in front of the bike and grab both front forks toward the bottom.

c) Try to "wiggle" the forks fore and aft; there should be no play.

d) With the wheel still elevated, slowly turn the handlebars lock-to-lock. You should feel no binding, looseness, or "bumpity-bumping" in the bars while turning; it should be free and smooth.

e) From a completely centered position, give the handlebars a gentle push to one side. It should fall to full lock smoothly, without binding. Return the bars to straight (centered) and repeat this test in the other direction. If there is a "detent" or looseness at the center, you probably need new bearings

f) If your steering (forks) "lock" in the centered position, and take a good amount of pressure to get them off of the centered position, then your steering head bearings are either over-torqued, or, more likely, worn out.


P.S.: a cheap and simple method for bearing removal and installation involves heating the bearing (so the ID of the race grows fractionally) while also cooling the shaft (so its OD shrinks). The combination of these two methods can make bearing work amazingly easier:

heating:



shrinking:



These tricks work well for steering head bearing replacement, wheel bearing replacement, tranny gears, etc.



Tapered Roller Bearings and Associated Parts:

Both original roller bearings (1992-98 XJ600 Seca II, XJ700, XJ750-X, 1984 XJ750RL Seca, all XJ900RK, RL, N/FN, and F models, XJ1100, and all XS1100 models) and kits to upgrade all other models to this improved style tapered bearings are offered. The aftermarket kits that we offer use only the highest quality, precision ground and assembled high-speed bearings available, and include both upper and lower dust seals.

Tapered bearings offer a vast improvement in performance and durability as compared to stock ball bearings. Additionally, you can increase the ring nut torque value to a slightly higher (25-30 foot-pounds) as opposed to original, thus even further reducing slop and play in your steering. ALWAYS MAKE SURE THAT YOU CHECK FOR BINDING AT ALL POSITIONS, INCLUDING FULL LOCK POSITIONS, WHEN CONVERTING FROM BALL BEARINGS TO TAPERED BEARINGS!

Here is a great video that shows the installation process for these tapered bearing sets:

https://www.xjbikes.com/forums/threads/xj750j-refurb.120254/page-2#post-609965

or, directly on you tube at:




And the races on models originally equipped with tapered roller bearings (1992-98 XJ600 Seca II, XJ700, XJ750-X, 1984 XJ750RL Seca, all XJ900RK, RL, N/FN, and F models, XJ1100, and all XS1100 models) can be especially tricky to remove, page 2 of this thread shows a creative way of removing them:

https://www.xjbikes.com/forums/threads/tapered-roller-bearing-insert-removal.130432


By the way, the rubber seals are installed with their “flat” side against the bearing:

www.xjbikes.com/forums/threads/triple-tree-dust-seal-which-way.117179/#post-586281




- FORK SWAPPING: R6 FRONT-END ONTO AN XJ650:

Taking cool to a whole new level:

http://xjbikes.com/forums/index.php?threads/40332



- DRIVESHAFT CROSS-JOINT EVALUATION:

Or is this you?:

"Everybody should go check their u-joints before you have my problem. I admit I like going fast, and doing hard starts. And it caught up with me.............my u-joint was within a few miles of complete self-destruction before I caught it, and the removed u-joint is scary. So if you've got over 50,000 miles on your bike, then this is critical!"

Here's how to check your driveshaft u-joint:

a) Put the bike on the centerstand, and put in 5th gear. Rotate the back tire back-and-forth. There should be minimal slack. If there is more than 1/2" of rotation, you may have a serious problem

b) Pull the swingarm boot on the shaft back as far as possible, and use a flashlight or a finger to probe for metal peelings on the arms of the joint. If you can feel shards or what feels like bent metal, replace the u-joint ASAP!

c) If you feel a vibration that shakes the whole bike, pull over and get the bike towed home. It's worth doing that, rather than ending up with a destroyed crankshaft, u-joint, driveshaft, or worse!

https://www.xjbikes.com/forums/threads/driveshaft-noise-vibration.129568




- SHOCKING INFORMATION!:

NOTE: on some models, you may come across the unfortunate situation of finding the upper shock mounting stud damaged, removed, or otherwise rendered un-usuable. Here is a solution to this dilemma:

http://www.xjbikes.com/forums/threads/rear-shock-stud-end-repair.62848/


- Rear suspension SAG is an important and almost-always overlooked factor in determining ride quality and rear suspension performance (handling and ride quality). Incorrectly-set sag not only effects the performance of the shock, but also of your front forks because as the ride height in the rear changes, the amount and rate of how the weight of the bike is transferred to the front forks changes, too. Sag can (and should be) adjusted whenever you install new shocks on your bike, or, if it’s never been checked and adjusted before, now would be a good time to do it!

http://www.factoryconnection.com/sag/



- WHEN U-HAUL JUST WON'T DO:

http://www.xjbikes.com/forums/threads/xj1100-manual-states-not-to-use-trailer.92844/

 

TIRES and WHEELS:


- TIRES:

What kind of shoes will the well-dressed XJ being wearing this year? Well, it's been said more than once that tires are about as personal as underwear, and there's a lot of truth in that statement (whether there is wisdom, also, can be debated though.......).

With the wide variety of black rubber donuts that are available for your steed, it's best to stop and consider a few major factors besides price alone when making such a critical decision........after all, your life literally rides on your tires (and only about 4 square inches of each tire at a time, to boot!).


1) How do you plan to ride? By this, we mean are you mainly an around-towner, a long-distance rider, or do you operate your bike just this side of the edge of sanity, and scrape pegs and other metals around every corner?

An honest assessment of what the majority of your riding style is will go a long way in determining what tires are going to be right for you. "Everyday" use and long-distance riding/touring benefits from a harder rubber compound and good rain dispersion abilities (assuming that you'll even take your jewel out in the wet!). And a harder rubber compound will give get you many more miles from a set of tires (figure 12 -15,000 miles on the front and 8 - 12,000 miles on from the rears on a hard compound tire).

Softer rubber compounds will grip like the devil, and allow you quicker, tighter, and more predictable carving of the twisties, but they usually handle poorly in the wet (or leaves, or gravel, etc.) and don't last very long (perhaps 8 -12,000 miles on the front and 5 - 10,000 miles on from the rears on a soft compound tire). In addition, tires such as these normally have a more "rounded" profile, so that the contact area of the tire with the pavement remains as large as possible when the tire is leaning over. "Cruiser" tires tend to be more "squared-off" at the top edge and is one reason they do not provide as much grip during aggressive cornering.


Of course, if that retro-appearance is important to you, we even offer old-skool, raised-white-letter tires for many models that convey a classic look to these timeless machines.



2) How much can I afford? Generally, the more expensive the tire, the better quality it is......we realize that there are exceptions to this rule, but like most other things in life, you get what you pay for. Be careful if you decide to go shopping for used tires----internal damage (too many potholes, resulting in fractured or ruptured belts, etc.) or other such issues may not be immediately apparent (or at all), and unless you know the history of the tire, well............

Also, you should be aware that tires have "date codes" cast into their sidewalls, and tires do have an expiration date (more or less).....and that's about 5 years from the date of manufacture. And it doesn't matter whether the tire is new and unused. Exposure to oxygen degrades certain of the chemical components in rubber that normally keep them flexible and "grippy", and so even an 5 year old brand new tire is a catastrophe waiting to happen. Tire date codes come in two different flavors, pre-2000 (3 digits) and post-2000 (4 digits) year of manufacture:


Pre-2000: 3 digits, with the first two being the week of manufacture (so these two digits can never be higher than "52"), and the third digit being the year of manufacture. Think of it as: WW/Y. So 3-digit date code such as "357" will mean the 35th week of 1997. Too old. Stay away. Save your money and your life........

Post-2000: 4 digits, with the first two again being the week of manufacture (so these two digits can never be higher than "52"), and the last two digits being the year of manufacture. Think of it as: WW/YY. So 4-digit date code such as "3507" will mean the 35th week of 2007.



3) What are the roads in my area like? Although this may seem like a silly question, certain roads (mainly on freeways) have "rain grooves" cut into them to help minimize water build-up on the roadways. While they may do a great job of accomplishing that, these grooves also try to "grab" and steer your bike, whether the roadway is wet or dry.

On front tires, there is a central, circumferential "guidance" groove on almost all street-bike tires. This groove helps to "steer" the bike straight and prevent wandering, especially at higher speeds----and it really works well. Unfortunately, it works really, REALLY well when it comes into contact with those rain groove cuts in a roadway............and a Battle Royale develops between your front tire and those grooves as they both fight for directional control of your bike. THIS IS NOT FUN and can be very dangerous.

So if your area has these rain grooves, or you like to ride off into far, distant, unknown sunsets where you might encounter these road cuts frequently, just be aware. To counteract this problem, some tires have either a "wavy", "zig-zag", or "interrupted" pattern to their central circumferential groove, which greatly minimizes this effect, but of course results in less of a tire-influenced "self centering action" than tires which have a straight and uninterrupted groove would experience.



4) Size does matter.....and bigger is not better or even safe on a motorcycle. Motorcycles are not quite like cars in terms of suspension dynamics.....mainly because you don't "steer" a motorcycle, you either lean it over or you put a greater pressure (via handlebar control) on one side of the tire or the other in order to change direction.

Motorcycle tires are thus extremely sensitive to the rim width which they are mounted on.......too big of a tire on a rim "squeezes" or "pinches" the tire, making the contact area either too rounded or deformed in other ways that result in a loss of directional control and cornering ability, as will too small of a tire (which tends to "flatten" the top of a tire). Our whole-hearted advice on tires is this: use the size that the bike manufacturer recommends, and like Goldilocks says, not too big, and not too small......unless you like twitchy, spooky, and unpredictable handling, that is. We all agree that really big, beefy tires look ultra-cool, but that misses the point. The original XJ rims are pretty narrow to begin with, and do not like larger-than-recommended tires to be stuffed onto them.

The correct tire sizes, load ranges, and inflation specs are listed on the sticker on the steering headpipe, or in your owner's manual (also listed below for reference). ALWAYS run the correct size tires, NEVER use a tire with a "load range" that is lower than is what is recommended (that's a trip to the hospital, or the morgue, just awaiting to happen.........), and always run the proper inflation pressures and check your tire pressures religiously. Tires leak air, oh yes they do, all of them, all the time.....even directly through the rubber itself. That is normal. You don't have to have a puncture of a bad inflation valve etc. to lose air pressure in a tire. Even a 10-degree change in outside air temperature will increase or decrease your tire air pressure.

NOTE: it is generally not possible to fit a larger rear tire on a stock rim on shaft-drive models due to interference with the driveshaft tube.



5) Where did my tire go? All about tire wear and life:

Besides mileage and tire "style" (soft or hard rubber compounding, as mentioned earlier) considerations, the number one killer of tires (besides potholes and locking your brakes!) is that worn out suspensions components----front forks and rear shock absorbers----will cause your expensive new tires to wear in both a rapid and an uneven, unsafe manner. If you notice that your old tires are worn unevenly side-to-side, or exhibit "feathered" or "scalloped" wear patterns, that's a sure indication of suspension wear, and needs to be addressed sooner, rather than later.

The generally accepted cause of front tire scalloping and feathering are incorrect compression and rebound settings . Incorrect compression results in scalloped, while incorrect rebound rates result in the "feathered" appearance.

Also, unbalanced air pressure in the fork tubes (on models so equipped) will cause uneven tire wear.

The next major factor is poor tire life expectancy has already been mentioned before, but here we go again: improper tire inflation pressures. Yes, it's a pain to constantly be checking them and inflating or deflating (adjusting) the pressures, but.............a necessary evil. And a cost- (and maybe a life-) saver, too boot.


One thing you can't do anything about, though: your front tire wears more on its left half simply because of the pitch of the road.....all North American roads have a slight "crown" to them and drop off from the center of the road towards the shoulders, in order to promote water drainage and object dispersion towards the shoulders. This slope causes you to actually be performing a very slight, unconscious but constant "lane-change" maneuver (to the left) that constantly wears on the left side of your tire.



6) Other factors to consider:

* Wheel bearings---inspect, re-pack, or replace when changing tires.
* Wheel....make sure it's not bent (measure the lateral and vertical runout), and clean off the inside of it where the tire bead seals against the rim......you'll need a "mirror finish" type of clean at this critical mounting point.
* Replaces the valve stems or the cores. The stems can leak thru their washer inside the wheel.
* Mounting and Balancing.....you can do it yourself. If you choose to have this work performed for you, then shop around. It will usually be much less expensive if you dis-mount the wheel and/or tire yourself.

We offer the special tools that you'll need to dismount, re-mount, and then balance your wheel/tire assembly. Here's a great how-to guide:

http://www.clarity.net/~adam/tire-changing.html


One issue to take into account when trying to balance your own tires is that some manufacturers provide a visual guide (on the tire itself) as to where the "light spot" is on the tire.

The following manufactures do mark the tire light spot via the following marks:

Bridgestone: a yellow ring.
Dunlop: a yellow circle
Kendra: a yellow dot.
NOTE: made by the same company as Cheng Shin brand.
Metzler: a red dot.
Pirelli: a red dot.


The following manufactures do not mark the light spot on their tires.

Avon.
Continental.
Michelin.

The following observations from user MiCarl sheds a few important thoughts on the issue of light-spot marks (or the lack of) that you should consider:

7) All you ever wanted to know about motorcycle tires:

http://www.motorcycleanchor.com/motorcycle/how_to/mc_tires.html

all brand tire specs at:

http://totalmotorcycle.com/photos/tire-tyre-guide/index.htm


http://www.foreven.com/motorcycles/Tyres/index.htm


LOAD RATING:

The importance of the load rating on a tire can not be overstated. A tire that is overloaded beyond it's design limit will run hot, wear fast and may quite literally blow out on you. The load the tire is designed to bear also affects it's shape and construction -- if you think about it, a GoldWing tire is not going to look like a GSXR600 tire. The load rating the manufacturer sets as the spec for your bike takes into account extra loading for weight-transfer (loading up the front wheel during braking, loading up the back wheel under acceleration), so you can't simply go by the curb weight of the bike. Always check the specs for your bike before ordering tires, and make sure the tires meet or exceed the load rating requirements for that wheel on that particular bike. For example, if the load requirement for the front wheel is "58" (520 lbs max), then you can fit a 59 or 60 weight-rated tire in the right size on there with no issue, but should never fit a 57 or below!


PR NUMBER:

The designation, ply number, refers to the tire load index. The PR marking is now only applied by the Japanese standard (JATMA. European standards (ERTO) do not require motorcycle tires to carry a PR number. The Japanese standard can be compared to the European standard as follows:
4PR - normal version
6PR - reinforced version
The PR number does not refer to the number of plies in the tire.


UNDER PRESSURE:

David Bowie says:


Yamaha says:
Maintaining proper air pressures in your tires is critical for both safety and performance....always check your tire air inflation for proper pressures before riding!

NOTE: "Load" is the total weight of rider(s), cargo, and accessories (It does not include the weight of the motorcycle itself, nor the fuel, oil, etc.). “Cold” means the ambient air temperature before you begin riding; in other words, the tires (and the air inside them) must not already have been heated by previous riding, nor from being stored (for example) in a heated garage before riding on a freezing cold day, etc. “Sustained high-speed riding” means for longer freeway (etc.) riding conditions.

The specification below are for bikes fitted with the stock size wheels and tires.

XJ550 Maxim :
load up to 198 lbs.: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-425 (max) lbs.: Front / Rear tire pressures: 28psi / 32psi cold
Sustained high-speed riding: Front / Rear tire pressures: 28psi / 32psi cold

XJ550 Seca and Euro:
load up to 198 lbs: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-423 (max) lbs.: Front / Rear tire pressures: 28psi / 40psi cold
Sustained high-speed riding: Front / Rear tire pressures: 28psi / 32psi cold

FJ600:
load up to 198 lbs: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-414 (max) lbs.: Front / Rear tire pressures: 28psi / 32psi cold
Sustained high-speed riding: Front / Rear tire pressures: 28psi / 32psi cold

XJ650 Maxim/Midnight Maxim:
load up to 198 lbs.: Front / Rear tire pressures: 26 psi / 28psi cold
load of 198-353 lbs.: Front / Rear tire pressures: 28psi / 32psi cold
load of 353-507 (max) lbs: Front / Rear tire pressures: 28psi / 40psi cold
Sustained high-speed riding: Front / Rear tire pressures: 32psi / 36psi cold

XJ650 Turbo:
load up to 198 lbs.: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-366 (max) lbs.: Front / Rear tire pressures: 32psi / 36psi cold
Sustained high-speed riding: Front / Rear tire pressures: 28psi / 32 psi cold

XJ650RJ Seca:
load up to 198 lbs.: Front / Rear tire pressures: 26 psi / 28psi cold
load of 198-353 (max) lbs.: Front / Rear tire pressures: 28psi / 32psi cold
load of 353-507 (max) lbs.: Front / Rear tire pressures: 28psi / 40psi cold
Sustained high-speed riding: Front / Rear tire pressures: 32psi / 36psi cold

XJ700 air-cooled:
load up to 198 lbs.: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-542 (max) lbs.: Front / Rear tire pressures: 28psi / 40psi cold
Sustained high-speed riding: Front / Rear tire pressures: 30psi / 32 psi cold

XJ700-X water-cooled:
load up to 198 lbs.: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-525 (max) lbs.: Front / Rear tire pressures: 28psi / 40psi cold
Sustained high-speed riding: Front / Rear tire pressures: 30psi / 32 psi cold

XJ750 Maxim/Midnight Maxim:
load up to 198 lbs.: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-507 (max) lbs.: Front / Rear tire pressures: 28psi / 32psi cold
Sustained high-speed riding: Front / Rear tire pressures: 32psi / 32psi cold

XJ750 Seca:
load up to 198 lbs: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-474 (max) lbs.: Front / Rear tire pressures: 28psi / 32psi cold
Sustained high-speed riding: Front / Rear tire pressures: 32psi / 36psi cold

XJ900RK:
load up to 198 lbs: Front / Rear tire pressures: 32psi / 36psi cold
load of 198-428 (max) lbs.: Front / Rear tire pressures: 36psi / 42psi cold
Sustained high-speed riding: Front / Rear tire pressures: 36psi / 42psi cold

XJ1100:
load up to 198 lbs: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-407 (max) lbs.: Front / Rear tire pressures: 28psi / 40psi cold
Sustained high-speed riding: Front / Rear tire pressures: 32psi / 36psi cold

XS1100:
load up to 198 lbs: Front / Rear tire pressures: 26psi / 28psi cold
load of 198-407 (max) lbs.: Front / Rear tire pressures: 28psi / 36psi cold
Sustained high-speed riding: Front / Rear tire pressures: 36psi / 40psi cold

Of course, there’s always a trade-off between tire traction and tire wear, which varies mainly due to riding style and tire inflation pressure . Lower pressures will typically increase tire temperatures, which then will soften the rubber and increase grip. This increased grip will cost you greatly in terms of tire tread life (and gas mileage) though. And total load (weight) will also affect tire temperatures -- the more weight , the greater the tire temperature (and thus the better the grip, and the less the tread life……..).

You should typically increase tire pressures when increasing the load. A good rule of thumb is to adjust your tire pressure such that the temperature increase causes the front tire pressure to increase 1 to 2 psi over cold, and the rear tire pressure increases 2 to 4 psi over cold (so, you will measure the tire pressures before riding (“cold”), and then measure the pressures after 15 or 20 minutes of riding. If the pressure increase is more than the above, add more pressure. If the pressure does not increase then you are over-inflated.

Running the tire at the maximum pressure under all conditions means sacrificing grip when lightly loaded.

All of the above motivates me to remind you that you should always “dress for the slide, not for the ride”……..



- WHEELS:

Although many Yamaha wheels are visually similar, they do not always interchange, as bearing sizes, speedometer drive gear differences (front wheels), and other factors do not allow a straight-forward swap.


Spoke Wheel Conversions:

A couple of considerations before you take the plunge:

http://xjbikes.com/forums/index.php?threads/29168

and

http://xjbikes.com/forums/index.php?threads/29004

and

http://xjbikes.com/forums/index.php?threads/29953

and

http://www.xjbikes.com/forums/threads/wire-wheels-and-a-150-rear-virago-700-style.34143/

and

http://www.xjbikes.com/forums/threads/mr-brown-to-the-rescue-the-535s-have-arrived.97004/



Front Wheel Removal and Installation:

front wheel installation:

http://xjbikes.com/forums/index.php?threads/24211


wheel bearings and their removal/replacement:

http://xjbikes.com/forums/index.php?threads/27529

and

http://www.xj4ever.com/wheel bearing replacement.pdf

and

http://xjbikes.com/forums/index.php?threads/35134


and don't forget the spacer flange:

http://xjbikes.com/forums/index.php?threads/18282

http://xjbikes.com/forums/index.php?threads/11100



Front Wheels:

NOTE: please note that the reference to "interchange" is used loosely: there may be differences in appearance (wheel style) as well as wheel size (diameter and/or width), as well as axle fitment, speedometer drive gear fitment, and brake disc attachment (and thus brake rotor type).


OEM front WHEEL # 4U8-25168-00-00
- straight 5-spoke design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 1.85 x 19"
- used on: XJ550 Seca models
- will interchange with......unknown. The speedometer drive gear unit is unique to this model, but is shares the same axle and bearings as all XJ550 - XJ900 model wheels.


OEM front WHEEL # 4H7-25168-20-98
- 10 spokes (5 sets of 2) "dual-spiral" design, aluminum wheel with polished rim and natural-finish spokes with low-gloss black painted trim
- size: 1.85 x 19"
- used on: XJ550 Maxim, XJ650 Maxim and XJ650RJ Seca, and all 1981-83 XJ750 Maxim and Seca models
- will interchange with Midnight Maxim wheel below.


OEM front WHEEL # 4H7-25168-20-8L
- 10 spokes (5 sets of 2) "dual-spiral" design, aluminum wheel with polished rim and natural-finish spokes with nebular gold painted trim
- size: 1.85 x 19"
- used on : XJ650 Midnight Maxim and XJ750 Midnight Maxim models
- will interchange with standard Maxim wheel above.


OEM front WHEEL # 16G-25168-29-4N
- angled "straight" quad-spoke design, aluminum wheel with polished rim and natural-finish spokes with silver painted trim
- size: 1.85 x 19"
- used on: XJ650 Turbo
- may interchange with the # 4H7-25168-20-98 or # 4H7-25168-20-8L wheels above.


OEM front WHEEL # 42H-25168-00-98
- straight 5-spoke design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 2.15 x 19"
- used on: all XJ700 and XJ750-X models
- will interchange with....nothing else, without a lot of experimenting and/or fabricating. Axles shaft and speedometer drive gear unit are unique to this model.


OEM front WHEEL 31E-25168-20-98
- angled "straight" tri-spoke design, aluminum wheel with polished rim and natural-finish spokes with low-gloss black painted trim
- size: 2.15 x 18"
- used on: FJ600, XJ750RL, and XJ900RK, RL, N, and FN models
- will interchange with #31E-25168-00-WG below.


OEM front WHEEL # 31E-25168-00-WG
- angled "straight" tri-spoke design, aluminum wheel with polished rim and natural-finish spokes with hi-tech silver painted trim
- size: 2.15 x 18"
- used on: XJ900 F models
- will interchange with #31E-25168-20-98 above


OEM front WHEEL # 4W1-25168-20-98
- 10 spokes (5 sets of 2) "dual-spiral" design, natural-finish aluminum with low-gloss black painted trim
- size: 1.85 x 19"
- used on: XJ1100 models
- will interchange with....nothing else, without a lot of experimenting and/or fabricating. Axles shaft and speedometer drive gear unit are unique to this model.



Putting rear wheels on the front? Either you love it or you hate it!:

http://xjbikes.com/forums/index.php?threads/28731

and

http://xjbikes.com/forums/index.php?threads/22043



Rear Wheels:

NOTE: please note that the reference to "interchange" is used loosely: there may be differences in appearance (wheel style) as well as wheel size (diameter and/or width), as well as brake drum (and thus shoes) diameter. On shaft-drive bikes, clearance to the swingarm may become an issue when going from a smaller to a larger width wheel.

Wheels that are larger in diameter than the stock size wheel will typically reduce the acceleration of the bike, but may increase top speed. Conversely, going to a smaller diameter wheel than stock will increase acceleration, but reduce top speed.


Rear Wheel Removal and Installation:

Typically, the axle shaft can become seized to the brake drum or the bearings. Sometimes a bigger hammer is the solution, but review these threads before you buy a 30-pound sledgehammer:

http://xjbikes.com/forums/index.php?threads/2398

and

http://xjbikes.com/forums/index.php?threads/575

and

http://xjbikes.com/forums/index.php?threads/1217

and

http://xjbikes.com/forums/index.php?threads/12364


wheel bearings and their removal/replacement:

http://xjbikes.com/forums/index.php?threads/27529

and

http://www.xj4ever.com/wheel bearing replacement.pdf

and

http://xjbikes.com/forums/index.php?threads/35134


and don't forget the spacers and the thin flange:

http://xjbikes.com/forums/index.php?threads/28615



OEM rear WHEEL # 5K5-25338-20-00
- 10 spokes (5 sets of 2) "dual-spiral" design, natural-finish aluminum with low-gloss black painted trim
- size: 3.00 x 16"
- used on: XJ550 Maxim models
- will interchange with XJ550 Seca models, but uses a larger diameter brake drum and shoes. Will not interchange with any of the larger cc XJ-series bikes.
NOTE: service manual specs says this wheel is 18" diameter but that is wrong!


OEM rear WHEEL # 4U8-25338-20-00
- straight 5-spoke design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 2.15 x 18"
- used on: XJ550 Seca models
- will interchange with XJ550 Maxim wheel, but uses a smaller diameter brake drum and shoes. Will not interchange with any of the larger cc XJ-series bikes.


OEM rear WHEEL # 4H7-25338-20-98
- 10 spokes (5 sets of 2) "dual-spiral" design, natural-finish aluminum with low-gloss black painted trim
- size: 3.00 x 16"
- used on : XJ650 Maxim models
- will interchange with XJ650 Midnight Maxim wheel below.
NOTE: smaller diameter brake drum than XJ650RJ Seca, XJ650 Turbo, and all XJ700 and XJ750 model wheels.


OEM rear WHEEL # 4H7-25338-20-8L
- 10 spokes (5 sets of 2) "dual-spiral" design, natural-finish aluminum with nebular gold painted trim
- size: 3.00 x 16"
- used on : XJ650 Midnight Maxim models
- will interchange with XJ650 Maxim wheel above
NOTE: smaller diameter brake drum than XJ650RJ Seca, XJ650 Turbo, and all XJ700 and XJ750 model wheels.


OEM rear WHEEL # 16G-25338-21-4N
- angled "straight" quad-spoke design, aluminum wheel with polished rim and natural-finish spokes with silver painted trim
- size: 2.15 x 18"
- used on: 1982 XJ650 Turbo
- will interchange with 1983 XJ650 Turbo wheel below; differs only in the painted trim color. Can also be used on all XJ650 Seca and XJ750 model bikes (except XJ750RL) and differs only in size and appearance. Can also be used on XJ650 Maxim and Midnight Maxim models, and has a larger diameter rear brake drum and shoes.


OEM rear WHEEL # 16G-25338-29-4N
- angled "straight" quad-spoke design, aluminum wheel with polished rim and natural-finish spokes with silver painted trim
- size: 2.15 x 18"
- used on: 1983 XJ650 Turbo
- will interchange with 1982 XJ650 Turbo wheel above; differs only in the painted trim color. Can also be used on all XJ650 Seca and XJ750 model bikes (except XJ750RL) and differs only in size and appearance. Can also be used on XJ650 Maxim and Midnight Maxim models, and has a larger diameter rear brake drum and shoes.


OEM rear WHEEL # 1FG-25338-20-98
- straight 5-spoke design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 3.00 x 16"
- used on: XJ700 non-X models
- will interchange with XJ700-X wheel below, and with all XJ650 Seca, XJ650 Turbo, and XJ750 model bikes (except XJ750RL) and differs only in size and appearance. Can also be used on XJ650 Maxim and Midnight Maxim models, and has a larger diameter rear brake drum and shoes.


OEM rear WHEEL # 1AA-25338-00-98
- solid center hub with cutouts to resemble a 5 "spoke" design. Aluminum wheel with a natural finish on the on left side, and a low-gloss black finish on the right side
- size: 3.00 x 16"
- used on: XJ700-X and XJ750-X models
- will interchange with XJ700 non-X wheel above, and with all XJ650 Seca, XJ650 Turbo, and XJ750 model wheels (except XJ750RL) and differs only in size and appearance. Can also be used on XJ650 Maxim and Midnight Maxim models, and has a larger diameter rear brake drum and shoes.
NOTE: larger diameter brake drum than XJ650 Maxim and Midnight Maxim model wheels, same size brake drum as XJ700 and all other XJ750 model wheels.


OEM rear WHEEL # 5G2-25338-29-98
- 10 spokes (5 sets of 2) "dual-spiral" design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 2.15 x 18"
used on: XJ650 Seca and XJ750 Seca models (except XJ750RL models)
- will interchange with all XJ700 and XJ750 model wheels (except XJ750RL) and differs only in size and appearance. Can also be used on XJ650 Maxim and Midnight Maxim models, and has a larger diameter rear brake drum and shoes.
NOTE: larger diameter brake drum than XJ650 Maxim and Midnight Maxim model wheels, same size brake drum as XJ700 and all other XJ750 model wheels.


OEM rear WHEEL # 10L-25338-20-98
- 10 spokes (5 sets of 2) "dual-spiral" design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 3.00 x 16"
- used on: XJ750 Maxim
- will interchange with XJ750 Midnight Maxim wheel below, and with all XJ700 and XJ750 model wheels (except XJ750RL) and differs only in size and appearance.
NOTE: larger diameter brake drum than XJ650 Maxim and Midnight Maxim model wheels, same size brake drum as XJ700 and all other XJ750 model wheels.


OEM rear WHEEL # 10L-25338-20-8L
- 10 spokes (5 sets of 2) "dual-spiral" design, aluminum wheel with polished rim and natural-finish spokes with nebular gold painted trim
- size: 3.00 x 16"
- used on : XJ750 Midnight Maxim models
- will interchange with XJ750 Maxim wheel above, and with all XJ700 and XJ750 model wheels (except XJ750RL) and differs only in size and appearance.
NOTE: larger diameter brake drum than XJ650 Maxim and Midnight Maxim model wheels, same size brake drum as XJ700 and all other XJ750 model wheels.


OEM rear WHEEL # 31E-25338-20-98
- angled "straight" tri-spoke design, aluminum wheel with polished rim and natural-finish spokes with low-gloss black painted trim
- size: 2.75 x 18"
- used on: XJ750RL and XJ900RK, RL, N, and FN models rear
- will interchange with #31E-25338-20-WG below


OEM rear WHEEL # 31E-25338-20-WG
- angled "straight" tri-spoke design, aluminum wheel with polished rim and natural-finish spokes with high-tech silver painted trim
- size: 2.75 x 18"
- used on: XJ900 F model rear
- will interchange with #31E-25338-20-98 above


OEM rear WHEEL # 4W1-W2533-20-98
- 10 spokes (5 sets of 2) "dual-spiral" design, aluminum wheel with polished rim and natural-finish spokes with low gloss black painted trim
- size: 3.00 x 16"
- used on: XJ1100 rear
- although it looks similar to the spiral-design wheels used on other models, the wheel bearing sizes, arrangement, and lack of rear brake drum makes this wheel unique.



TIRE SPECIFICATIONS:

NOTE: all original XJ-series rim are designed to take tubeless tires (and all of these bikes did, indeed, come with tubeless tires from the factory. You can use tube tires if you want.

http://xjbikes.com/forums/index.php?threads/8511

and

http://xjbikes.com/forums/index.php?threads/12802




Front wheel and tire specs:

90/90-18 tires:

FJ600
- F14TL Dunlop



100/90-18 tires:

XJ750RL
XJ750E-II
XJ900RK/RL, F, N, FN, P models:
- all use a 2.15 x 18" aluminum wheel with 0.5mm max lateral and 1mm vertical runout allowed.
- original tire was a Pirelli or Bridgestone 100/90-18 (same as a 3.25/3.50 or MM90) V-rated
- tire pressures:
up to 200 pound load: 32psi
200-425 (max) pound load: 36psi
high-speed riding: 36psi



90/90-19 tires:

XJ550 Seca model:
- uses a 1.85 19" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 3.00H x 19, same as a 90/90 or MJ90 4PR
NOTE: same size front wheel as next group, which uses the 100/90-19 tires.
- tire pressures:
up to 200 pound load: 26psi
200-425 (max) pound load: 28psi
high-speed riding: 28psi



100/90-19 tires:

XJ550 Maxim model:
- uses a 1.85 x19" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 3.25H x 19, same as a 100/90 or MM90 4PR
- tire pressures:
up to 200 pound load: 26psi
200-425 (max) pound load: 28psi
high-speed riding: 28psi


XJ650 models:
XJ650 (USA) Maxim and Midnight Maxim models:
- uses a 1.85 x 19" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 3.25 x 19, same as a 100/90 or MM90 .
- tire pressures:
up to 200 pound load: 26 psi
200-353 (max) pound load: 26psi
353-507 (max) pound load: 28psi
high-speed riding: 36psi (32psi in the 1982-83 Maxim, according to the owners manual)


XJ650 (Canadian) Maxim and Midnight Maxim models:
- uses a 1.85 x 19" aluminum wheel with 2mm max vertical or lateral runout
- original tire was a Bridgestone 3.25 x 19, same as a 100/90 or MM90 .
- tire pressures:
up to 200 pound load: 26 psi
200-331 (max) pound load: 26psi
331-478 (max) pound load: 28psi
high-speed riding: 32psi


XJ650 Turbo:
- uses a 1.85 x 19" aluminum wheel with 0.5mm max vertical and 1.0mm max lateral runout allowed.
- original tire was a Bridgestone or Dunlop 3.25 x 19, same as a 100/90 or MM90 4PR rated
- tire pressures:
up to 200 pound load: 26psi
200-366 (max) pound load: 32psi
high-speed riding: 28psi


XJ650RJ/RJC Seca:
- uses a 1.85 x 19" aluminum wheel with 0.5mm max vertical and 1.0mm max lateral runout
- original tire was a Bridgestone or Dunlop 3.25 x 19, same as a 100/90 or MM90 4PR rated.
- tire pressures:
up to 200 pound load: 26 psi
200-353 (max) pound load: 28psi
353-507 (max) pound load: 28psi
high-speed riding: 32psi


XJ650 UK (4K0) model:
- uses a 1.85 x 19" aluminum wheel with 2.0mm max vertical or lateral runout allowed.
- original tire was a 3.25 x 19, same as a 100/90 or MM90 4PR rated.
- tire pressures:
up to 200 pound load: 26 psi
200-353 (max) pound load: 28psi
353-507 (max) pound load: 28psi
high-speed riding: 36psi


XJ650P Police models:
- uses a 1.85 x 19" aluminum wheel with 0.5mm max vertical and 1.0mm max lateral runout allowed.
- original tire was a 3.25 x 19, same as a 100/90 or MM90 4PR rated.
- tire pressures:
any load: 28psi


XJ700 all models and XJ750-X models:
- uses a 2.15 x 19" aluminum wheel with 2mm max lateral or vertical runout allowed.
- original tire was a Bridgestone or Dunlop 3.25/3.50 x 19, same as a 100/90 or MM90 57H
-tire pressures:
up to 200 pound load: 26 psi
200-525 (max) pound load: 28psi
high-speed riding: 30psi


XJ750 all models except XJ750RL, XJ750E-II, and XJ750-X:
- uses a 1.85 x 19" aluminum wheel with 2.0mm max vertical or lateral runout allowed.
- original tire was a Bridgestone or Dunlop (Maxim models) 3.25H x 19, same as a 100/90 or MM90 4PR rating
- tire pressures:
up to 200 pound load: 26 psi
200-507 (max) pound load: 28psi (note: max load is 474 pounds for Seca models)
high-speed riding: 28psi (1982 Maxim models)
high-speed riding: 32psi (1983 Maxim and Midnight Maxim, and all Seca models)


XJ1100 models:
- uses a 1.85 x 19" aluminum wheel with 2.0mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 3.50 x 19, same as a 100/90 or MM90 4PR or H rated
- tire pressures:
up to 200 pound load: 26 psi
200-407 (max) pound load: 28psi
high-speed riding: 32psi




Rear wheel and tire specs:

110/90-18 tires:

XJ550 Seca models:
- uses a 2.15 x 18" aluminum wheel with 2mm lateral or vertical max runout allowed.
- original tire was a Bridgestone 3.50/4.10 x 19, same as a 110/90 or ML90 61H
- tire pressures:
up to 200 pound load: 28psi
200-425 (max) pound load: 40psi
high-speed riding: 32psi



120/90-18 tires:

XJ650RJ/RJC Seca models:
- uses a 2.15 x 18" aluminum wheel with 0.5mm max vertical and 1.0mm max lateral runout allowed.
- original tire was a 4.00/4.40 x 18, same as a 120/90 or MN/MP/MR-90 65H
- tire pressures:
up to 200 pound load: 28psi
200-353 (max) pound load: 32psi
353- 507 (max) pound load: 40psi
high-speed riding: 36psi


XJ650 Euro 4K0 models:
- uses a 2.15 x 18" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a 4.00/4.40 x 18, same as a 120/90 or MN/MP/MR-90 65H
- tire pressures:
up to 200 pound load: 28psi
200-331 (max) pound load: 36psi
331-478 (max) pound load: 40psi
high-speed riding: 40psi


XJ650 Turbo models:
- uses a 2.15 x 18" aluminum wheel with 0.5mm max vertical and 1.0mm max lateral runout allowed.
- original tire was a Bridgestone or Dunlop 4.00/4.40 x 18, same as a 120/90 or MN/MP/MR-90 V-rated
- tire pressures:
up to 200 pound load: 28psi
200-366 (max) pound load: 36psi
high-speed riding: 32psi


XJ750 Seca models:
- uses a 2.15 x 18" aluminum wheel with 2mm lateral or vertical max runout allowed.
- original tire was a Bridgestone 4.00/4.40 x 18, same as a 120/90 or MN/MP/MR-90 65H
- tire pressures:
up to 200 pound load: 28psi
200-474 (max) pound load: 32psi
high-speed riding: 36psi


XJ750 Police models:
- uses a 2.15 x 18" aluminum wheel with 0.5mm max lateral and 1mm vertical runout allowed.
- original tire was a 4.00/4.40 x 18, same as a 120/90 or MN/MP/MR-90 65H
- tire pressures:
all loads: 32psi


XJ750RL, XJ750E-II, and XJ900 models:
- uses a 2.75 x 18" aluminum wheel with 0.5mm max lateral and 1mm vertical runout allowed.
NOTE: 2mm lateral or vertical max runout allowed on XJ900RK, RL, and P models.
- original tire was a Pirelli or Bridgestone 4.00/4.40 x 18, same as a 120/90 or MN/MP/MR-90 V-rated
- tire pressures:
up to 200 pound load: 36psi
200-425 (max) pound load: 42psi
high-speed riding: 42psi



130/90-16 tires

XJ550 Maxim model:
- uses a 2.15 x 16" aluminum wheel with 2mm max lateral or vertical runout allowed.
- original tire was a Bridgestone 5.00/5.10 x 16, same as a 130/90 or MT90 67H
- tire pressures:
up to 200 pound load: 28psi
200-425 (max) pound load: 32psi
high-speed riding: 32psi


XJ650 Maxim and Midnight Maxim (USA) models:
- uses a 3.00 x 16" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 5.00/5.10 x 16, same as a 130/90 or MT90 67H
- tire pressures:
up to 200 pound load: 28psi
200-353 (max) pound load: 32psi
353-507 (max) pound load: 40psi
high-speed riding: 40psi (note: 36psi in owners manual)


XJ650 Maxim and Midnight Maxim (Canadian) models:
- uses a 3.00 x 16" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 3.25 x 19, same as a 100/90 or MM90
- tire pressures:
up to 200 pound load: 28psi
200-331 (max) pound load: 32psi
331-478 (max) pound load: 40psi
high-speed riding: 36psi


XJ700 all models and XJ750-X model:
- uses a 3.00 x 16" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 5.00/5.10 x 16, same as a 130/90 or MT90 67H
- tire pressures:
up to 200 pound load: 28psi
200-525 (max) pound load: 40psi
high-speed riding: 32psi


XJ750 Maxim and Midnight Maxim models:
- uses a 3.00 x 16" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone or Dunlop 5.00/5.10 x 16, same as a 130/90 or MT90 67H
- tire pressures:
up to 200 pound load: 28psi
200-507(max) pound load: 32psi
high-speed riding:
1982 models: 32psi
1983 models: 36psi


XJ1100 models:
- uses a 3.00 x 16" aluminum wheel with 2mm max vertical or lateral runout allowed.
- original tire was a Bridgestone 5.00/5.10 x 16, same as a 130/90 or MT90 67H
- tire pressures:
up to 200 pound load: 28psi
200-407 (max) pound load: 40psi
high-speed riding: 36psi




- Life Inside A Tire:

Well, why not?

www.youtube.com/watch?v=rILyBg7ZjeI