Running into some problems with my '81 xj550 project

Hi everyone!

This is my first post on this forum, but I have gotten a lot of very helpful information from you guys that has helped me with my bike. I bought my ’81 Maxim xj550 last summer as a summer project. It was not running and had been sitting in the backyard of the previous owner for a year or so.

I fully disassembled the bike, stripped and repainted it, and cleaned everything I could. I wasn’t getting spark on two of the plugs, so I replaced the spark plugs, pick up coil (one of the coils wasn’t working), and one of the ignition coils (wasn’t testing right). After giving the carbs a thorough cleaning I got the bike to run. I replaced the rear sprocket and chain, disassembled and cleaned the master cylinder and brake piston (they didn’t need a rebuild). I also replaced a bent front wheel and both tires.

I tried to replace the fork seals but the bolts in the bottom were stripped so I only changed the fork oil (probably need to get to that at some point). The rear brake has no sign of delamination and there is a lot of life left in the front pads. I also had to do some minor re-wiring in the indicator switch and replaced oil and air filters.

When I put the bike back together it was running decently, but there were a couple problems. The mixture is rich (I am about 5000ft above sea level). There are also some quirks with the gearbox.

Sometimes I would have trouble starting it, and this problem got worse after a while despite getting a new battery. Every sixth or so time the engine would turn over but not catch. When the engine did catch if I didn’t support it with the throttle then it would die and wouldn’t start for a half hour or so. I had more problems when the engine was warm, and less frequently when the engine was cold or hot.

At a certain point the motorcycle stopped starting. The engine would only turn over a couple times before the solenoid would click and it wouldn’t turn any more. Pretty much any time I wanted to ride it I had to give it a jump, but that didn’t always work either. Eventually it didn’t turn over at all but instead the solenoid would click. Thankfully, I had gotten it home by then. It sat in my garage for a couple months until I decided to try to get it running again. I took the starter motor out, figuring that I might have burnt it out because of the starting troubles. It didn’t spin, and I took it apart and found it filled with black dirty oil/grease, I was thinking that maybe starter fluid had permeated into the starter dripping from the airbox. I cleaned it but lost one of the thrust washer, so I bought a professionally rebuilt starter and while I was waiting for it to come in I checked valve clearances. Several of them were out of tolerance. I tried to use the Zip-tie technique to remove and measure shims but had no luck, so I put the cover back on with a new gasket to see if the new starter would allow me to start it up. Although the starter spun well and the motor turned over, it didn’t catch.

I figured I would ask you guys for your suggestions before I went any further. I want to take the carbs off and make sure they are clean (I never cleaned the emulsion tube in the carbs and I also had left the fuel petcock on prime while it was sitting). I think the gas tank might not be the cleanest so deposits may have plugged some of the smaller ports. I want to also replace the fuel lines and install a filter. I really would prefer to not deal with the valve shims right now. Although I know that it is something that I really need to do I am pretty intimidated with dealing with the engine. Do you guys think that the valve clearance issue is to blame for not starting? Also I would appreciate any suggestions you have about my project. I have the valve measurements somewhere; I will try to post them later today.

Thanks a lot guys!

-Ilya

 

ilyamer,

Welcome to the Club. You've come to the right place. Loads of knowledge here. Remove your oil filler cap and sniff for gas. If it smells like gas you do not need to try to start your bike. Drain and replace the oil with 4T motorcycle oil (Autozone). You need to get those valves in spec and do a compression test with a fully charged battery. The members here will guide you through. Hope this helps.

Gary

 

Stop being intimidated and get your valves in spec. Your symptoms could very well be at least partially attributable to tight clearances, and the more you run the motor the better chance you'll harm it.

Then you need to properly service the carbs, which does involve removing and cleaning things like the emulsion tubes.

Then you'll need to sync and tune those carbs, something you CANNOT DO if the valves aren't in spec.

Get a service manual if you don't have one. The aftermarket book for the 550s is the Clymer, it's ok; a factory book is better, and the best is to have both.

Then go through the "maintenance" section. The VERY FIRST ITEM is the valve clearances. There's a reason for that.

Then we'll talk about how dangerous 30-year old brake lines are, and the fact that you probably will need new alternator brushes.

VALVES FIRST. Check them now.

 

Thanks for your help guys.

rocs- My oil does indeed smell like gas- what does that indicate?

I guess there really is no way of getting around the valve clearances. Ill give it another try tomorrow and hopefully ill be able to get the tool to work. Here are the clearance measurements, in mm:
1 2 3 4
E .063 .152 .178 .203

I .178 .076 .152 .102

I used a set of feelers from Autozone, are they going to be precise enough? How accurate do the measurements have to be?

 

There's no way you could be that accurate. The thinnest gauge is 0.03 mm. For example, how could you measure 0.063 mm? The third digit after the zero doesn't make sense.

 

He's using standard feeler gauges -

Those are metric conversions.

 

Since you only got questioned and didn't get your question answered, let me help.

If your oil smells like gas, either your float(s) aren't stopping the flow of gas properly (they work similar to a toilet-when the fuel reaches ~1mm from bowl top, if set correctly, the float pushes up a needle valve which halts the fuel) or your rings aren't sealing properly<--less likely.

Exhaust #1 is critically tight, E#2 just tight, I#1 is loose, I#2 too tight, I#4 just tight-these could def. contribute to the strange behavior. The process of fixing them isn't very hard-but does require patience and following the proper procedure-but you can do it for sure. Once you know the number for the existing shims it's easy to determine what goes in-and you can get them here or usually swap some to get them in spec.

To use the tool you MUST make sure it is as close to perfectly centered on the bucket as possible. I used a really bright light, some reading glasses, and then held it firm and tight while I slowly tightened it down. I also made a tool for popping the shim out of a metal CPU chip puller to make the whole thing easier. If you like I can show you the link on here with a pic of it.

Be sure and change your oil often and use Motorcycle specific 20w50 to help with the gearbox issue. Also since your riding in high altitude be sure and use low octane fuel. Your starved for O2 so you need a quicker burn.

I have an 81 XJ550 also and had some issues after I first bought it-but they are all sorted now. It can be done and they are really great bikes. Awesome gas mileage and will get to 100mph and past as fast as you would ever need to.

 

Correct on all of the above. You have carb/float issues as well as a couple of scary tight valves.

The shims come in .05mm size increments; you want to be as accurate as possible BUT there's no sense fretting over .001" tolerances. Using "standard" (American) feelers with metric equivalents will work, but you can drive yourself crazy in the process.

Since this is something you'll need to do every 5000 miles anyway, I'd suggest investing (less than $10) in a set of "pure" metric feelers. K-D Tools' #2274 is widely available; you can quite often find them in stock at a NAPA or other auto parts with a K-D display, or online.

You did find these articles, I trust?

Valve Clearances: http://xjbikes.com/Forums/viewtopic/t=14827.html

Part Deux: http://xjbikes.com/Forums/viewtopic/t=29209.html

Mikuni breakdown: http://xjbikes.com/Forums/viewtopic/t=31061.html

Petcock rebuild: http://xjbikes.com/Forums/viewtopic/t=25058.html

You'll need this within 500~800 miles after you start riding the bike: http://xjbikes.com/Forums/viewtopic/t=19538.html

This is really important: http://xjbikes.com/Forums/viewtopic/t=15874.html

This one's not in either book: http://xjbikes.com/Forums/viewtopic/t=35134.html

But you still need a service manual.

Oh, and your "gearbox issue" is probably more of a clutch adjustment or drive chain thing. But you have a lot more important things to worry about first; like 30-year old brake lines, and not blowing up the motor.

 

MercuryMan wrote: "Since you only got questioned and didn't get your question answered, let me help".

MM,

2:52am?...I was sleep. :lol: Thanks for answering tho.

Gary

 

Thanks a lot for your input, I appreciate all of your help. I don't feel like I am going through this process alone anymore. You have rekindled my interest in working on the bike!

That link showing how the tools work was very helpful, definitely makes me a lot more confident. Hopefully I will get a chance today to check the clearances again (going to invest in a set of metric feelers, might as well do it right) and measure the shims. Do you guys recommend getting new shims from chacal?

 

You don't have to measure shims, thickness is stamped in the back of each one.

As far as I know, shims are reusable, and you should be able to get those you'll need from other members.

 

Actually...sometimes you do have to measure shims. Occasionally I've found one that got put in the wrong way round and the numbers wore off. Even when put in correctly the numbers can wear enough (on a higher mileage/ abused bike) to be difficult to read. Digital calipers are pretty inexpensive, and easier to read then the traditional dial caliper (though dial calipers aren't too hard to use either).

 

I have a caliper so I was going to measure them just to be sure. The Clymer manual reccomends it.

How would I go about getting shims from members?

 

Member HogFiddles runs a "shim pool." Contact him for specifics.

 

Hey guys!!

Thought it was time for an update. A couple days ago I got in a bunch of parts I ordered. So far I've:
Adjusted valve clearances- this was a lot less scary than I thought it would be. Once I took out the first couple of shims I got the hang of it and it went very smoothly after that.
Replaced brake lines- stainless steel, baby!!
Replaced gasket, pressure washers on valve cover (the old, hard pressure washers are such a pain to get off)
While I had the valve cover off I cleaned it up, it looks much nicer.
Replaced front sprocket

I also took the carbs completely apart and cleaned them really well. I ran into a problem though. I had some trouble trying to remove one of the carb butterflies. I ended up stripping the screw, and I used a screw remover to get it out. Even though I tried to be gentle with it, I ended up bending the throttle rod and butterfly plate, and while trying to remove the plate from rod ended up bending up the carb body (I tried putting another throttle rod in there after I got the bent one out and it wouldnt go in very easily). I decided to by a donor rack of carbs from ebay, The seller said they were from a 550 seca, which should have the same carbs, right? They are minukis, but they are a bit different and I dont think they will work. They have fuel lines going into more than one spot, which my minukis dont do. Ill attach pics of my carbs (the set of 3) next to these other ones, do you guys know what they are from?

 

I'm not aware of any Yamaha Mikunis with top hats like those. They're NOT from a 550 Seca, I can tell you that much for sure. Looks like the enrichment plungers are located slightly differently as well. Might be from a Suzuki even.

The reason the butterfly screws are so hard to get out is they're split-peened on the backside so they won't come loose. You have to file the "butts" off the screws before attempting to remove them. The use of a proper JIS screwdriver is also highly recommended.

There are slight differences between carbs on the 550 Seca and 550 Maxim too; pilot air jets and main jet (slide) needles. When you do find a correct replacement carb body, you'll want to swap those over from your original carb if the replacement didn't come off a Max.

 

Alright, so I got the spare rack of carbs, took off the body I needed, cleaned it up and reassembled everything. I put it back in the bike, installed a fuel filter, and filled them up with gas. Put on the choke, pressed the start button and the motor turned over, but there was nothing. I sprayed starter fluid into the airbox, but that didnt do anything. It sounded like it maybe was slightly firing, but not catching, although I might have imagined it. Thinking it may be the ignition coils I checked primary and secondary resistances. The manual says they should be 2.5 and 11000, but I measured around 5 for the primary on both and couldnt get anything for the secondary resistance, even with the meter on 200k ohms.

So I guess my coils are shot. Do I have any options besides OEM? I used a spark tester on all plugs and it said I am getting spark, would insufficient spark keep the engine from running?

 

Also I am not sure this matters, but when I was checking the spark i was shocked by the lead.

 

Only if you spill your beer in the process of being shocked {

BIG voltage in there so it's a common thing. Could mean your wire is breaking down and losing it's ability to insulate the large V potential, normally that is no big deal-you can just replace the wires easily. It can be done on our bikes but is a little bit more work since the wires are 'hard' wired into the coil-in other words surgery is required. Could also be that you were close enough to the discharge that it traced along the outside of the wire and found you.

 

aftermarket coils available here:

http://www.xjbikes.com/Forums/viewtopic/t=14561.html

What's the state of your battery? These bikes will not style unless they get a full belt from a good battery. Get it load tested if any doubt.

 

These bikes are always styling! Starting with a weak battery is something of a pain though.

Ghost

 

Let's back up and run over a couple of basics:

Did you accurately WET-SET the float levels to spec? http://www.xj4ever.com/setting%20fuel%20levels.pdf

Did you bench-sync the carbs?

Did you install a BRAND NEW set of properly gapped NGK D8EA's?

These items are critical to getting it fired after rack surgery. Are your valves in spec?

 

My battery is in good shape- I bought it last August and It is on the tender while I'm not riding the bike. Doesn't matter though, I used one of those external jumpers to turn it over anyway. I did a bench sync of the carbs, but no float adjustment. My valves are in spec. I guess when I get home today ill pull the carbs back off and check the floats, my oil did previously smell like gas after sitting for a while so ill smell it again. Maybe the floats aren't closing off and gas is flooding the engine.

 

One or two floats, low or high, can make it difficult to start on a "default" sync.

And buy some NEW plugs.

 

Okay, so before I left my house today I gave a sniff to my oil, and it definitely has gas in it. Float problems it is! Tonight i'm going to pull off the carbs and go through the float levels, put in some new plugs, change the oil and see if she'll start. I didn't know float levels contribute to mixture, my bike always ran rich but I figured that was because I am at altitude. Perhaps the float levels had something to do with it too.

Also, do you guys know how big the gap of the spark plugs should be for the 550s? Ill adjust them all before i put them in.

 

For the 550s the factory specified gap is 0.6~0.7mm (.024"~.028")

I start at .025" since they widen as the plug wears.

Be careful not to overfill on the oil change, 2.5 qts is about it...

 

So I got the carbs out and set them up. Three of the carbs overflow. Is this because of my needles or poor float adjustment?

 

Could be either one.

Could also be that the o-rings on the outside of the float valve seats are shot.

I'm not sure how far apart you took the needle/valve assemblies; see: http://xjbikes.com/Forums/viewtopic/t=31061.html

 

I took the carbs all the way apart, so i had both out. Is there any way to tell without just bending the float tab and seeing if it stops? Also, the spare rack of carbs has internals that look much shinier than mine, should I just swap all the needles and float valve seats now before I start messing with it? They look in better condition. I don't know how frequently those needles stop sealing properly, but I know my bike was neglected for most of her life =(

 

I took the carbs all the way apart, so i had both out. Is there any way to tell without just bending the float tab and seeing if it stops? Also, the spare rack of carbs has internals that look much shinier than mine, should I just swap all the needles and float valve seats now before I start messing with it? They look in better condition. I don't know how frequently those needles stop sealing properly, but I know my bike was neglected for most of her life =(

 

Based on your replies and questions, I have a feeling you're not looking at the stuff we've posted links to.

Are you using clear tubing attached to the drain plugs to see what is happening? As shown here: http://www.xj4ever.com/setting%20fuel%20levels.pdf

Did you replace the o-rings on the OUTSIDE of the VALVE SEATS, you can see one here: http://xjbikes.com/Forums/viewtopic/t=31061.html

Examine the tips of the needle valves for wear. Shine a flashlight into the valve seats and see what they look like. Polish with a q-tip and metal polish, clean thoroughly, and inspect for wear. Replace if worn, likewise for the valve needles.

 

Fitz, sorry it seemed that way, I glanced past the o-ring thing because I was too anxious for a quick fix. I really appreciate your help!
I polished the valve seats and set up a mount to set float levels. Three of my carbs were leaking because of the o-rings. I soaked the valve seats into carb cleaner without removing the rubber, and they were rock hard. I replaced them with ones from auto zone, set floats, and put the carbs back on the bike. It still didn't start well. I checked my plugs even though I replaced them about 6 mo ago, and they were the wrong kind. During the fall I had taken the old plugs into an auto parts store and gotten matches without even considering that they were incorrect for the bike. After making sure the gaps were correct I put them in and my bike started right up. It starts almost immediately now, I even forgot to take my key out once and the headlight killed the battery, and it took only a couple feet to push start it. It feels so great to have it running as it should. This weekend I am going to do an on-bike carb sync and then I'll be ready for riding!

 

I have a question though, I read on here about how to fabricate a homemade YICS tool, but I can't seem to find the link. Do any of you guys have the link handy? Also, I read somewhere that you can put an oil-soaked rag into the YICS hole- does this method actually work?

 

Hi, I can't find dimensions now you mention it but found this which may be of use to you, link to Rick Massey's YICS rag/t-shirt technique...

http://xjbikes.com/Forums/viewtopic/t=3 ... +yics.html

Also I believe Chacal of XJ4ever sells a very nice repro YICS tool for around $35 IIRC and it's worth it really for the use you'll get from it.

If you really REALLY want to make your own I'll measure mine & do a diagram later if you want.

 

I found the link-this is the homemade YICS tool I was talking about:
http://www.xs11.com/xs11-info/tech-tips ... -tool.html
I have a question though- he says that you should adjust mixture screws to 1.5 turns out, is this something I should do? Do I adjust it back after? I haven't tuned the mixture so all of the screws are 3 turns out.

 

It depends whether you have coarse or fine threads, it's mentioned in the carb threads somewhere I'm sure (coarse 1-1.5, fine 2.5-3).

You need to play with the mixture screws when you colortune anyway as the 3 turns is just a basic "get you running & sync'd" setting. As long as your engine will tick over you should be fine with them as-is for sync...

 

Two things:

For the Mikunis on the 550s, 3 turns out is a good starting point. Mixture screws are NOT the sync screws; leave the mixtures at 3-out until after you've done your initial running vac sync. THEN do your mixture tuning; and touch-up the sync again afterward.

That particular YICS tool has a glaring omission that will prevent it from working correctly. It needs a SEAL of some sort between the "3/4" fender washer" and the side of the cylinder casting. A leak there would constitute a major vacuum leak and throw off your sync efforts.

 

All mik's have fine thread pilot screws then? Cool.

I don't think he was confusing them with the sync screws, was just confused as the guy was giving basic settings for Hitachi coarse pilot screws & as it was different to his already-found base setting, wondered if it was something he'd got wrong or if they had to be wound in before synching...

I can't get that page to work "403 forbidden" message, but that yics design without rubber washer seems to be floating around various places in the net "ether" with the same major omission!