Complete XJ650 Rebuild

Hey everyone,
Looking for a lot of guidance on my first rebuild. I have been combing through these forums and anything else I can find on my bike preparing for a complete overhaul of a bike I bought just over a year ago.

To give you a little back-ground on this... This is my first bike, I have ridden a little bit when I was younger on dirt bikes, etc. I have never rode a road bike and was very interested in learning about motorcycles. If anything this is more of a challenge for me as I am the type of person that like to understand things by tearing it apart and learning that way.

Like I said I bought this bike awhile ago and it was in a sad state. It was left in an alley for a couple years, knocked over and left for dead. I bought it for $250, moved it to my house and a friend of mine rode it around to let me know if anything was majorly wrong. It started fine but slipped in 2nd and that is all I know about it.

I started taking things apart to clean, change out, and again trying to understand. I am looking to give this bike a bit more of a cafe / brat style look but that is not why I am starting this thread quite yet. Over the past year I have torn down almost every single nut and bolt of this bike, found some pretty unfortunate things along the way and even possibly did somethings I shouldn't have (now knowing, I won't be making those mistakes again).

While I was doing that I also built my own sand blasting booth and powder coating oven. I told you I like to do everything myself and if it requires me making something to do it, I will.

I have attached some pictures of what I have done so far (it was all I grabbed along the way but will be taking much more as I put things back together).

My main goal for this thread is I am going to need some help with assembling my engine back together, information I need that I haven't really found in other threads or diagrams, maybe other ideas for my bike I haven't approached yet, and just somewhere to share my experiences with other people.

With that said, attached are some pictures. One of my frame chopped for a new seat. My first powder coating experience on my rims (which turned out pretty good I think). One of the problems I found getting into my engine. Some randoms.
I will have my first questions later today and maybe a few more pictures.

 

Back end of my frame, loop was made for the seat I purchased about 6 months ago.

 

Yikes, that gear is a mess. Good project, I'm also building a 650 from the ground up but I didn't need as much engine work.

 

Yea that gear is what I found when I got the cases apart. I also found this which I believe was why the 2nd gear was slipping:/
Taking the whole engine apart might not of been the best thing for me to do being my first bike but after finding this I am kinda glad I did.

 

Well with that kind of repair, you have to split it anyway. I was on the fence with mine when the motor was out/head torn down, the chain guides are not broke but they all break at some point. It'll be worth it, you can replace those chain guides too and be done with it, shouldn't have to split again for a long time.

 

I have an XJ650 Seca I've parted out. Let me know if there are any parts you could use.

 

Did you also happen to find that the alternator chain guide was broken? A broken shifting fork is really uncommon; I don't think I've heard of one failing (aside from being bent) without something else letting loose first.

 

K-Moe, to be honest I am not 100% sure.
I started tearing this apart months ago (stopped for a while to finish building my oven) so I have part both at my shop and my house. When I get everything back in one spot I will let you know.

 

BTW, your powder coating work looks great! I'm about to send another batch of parts off to be coated. Wish I had the room at home for a small setup, it's addicting.

 

My God, some riders are rough with their bikes !

I just bought an XJ900 with the same slipping 2nd gear issue, I'm anxious to see what I'll find in there.

 

OK. Even if the guide isn't broken it is good insurance to replace it, and to rebuild the starter clutch while the engine is apart.

 

Hopefully it's just the more common worn dogs (or even better; a slipping clutch).

 

Yeah, knock on wood.

 

Updated picture of some coating I did tonight. Both bottom cases done, Top halves later this weekend. Will be needing the help as I start putting the cases back together.
I found a thread on rebuilding the starter clutch with the bottom cases together but nothing about it where I am at the stage I am.

 

The starter clutch can't be rebuilt with the cases together (without cutting a window in your cases; not advised). That rumor was debunked a long time ago.

You already have the starter clutch out, so rebuilding it is as simple as ordering a set of springs and rollers from Chacal (along with a new alternator chain guide. Reusing the old one is inviting disaster).

 

Welcome aboard. You're at the right spot for all things XJ.

Gary H.

 

Alright some updates.

I might not have mentioned before but I am coating a case I bought since the original case that was on my engine had a large crack in the bottom half. My plan was to tear the original engine apart, add in this "newer" case and hopefully keep all the internals (excluding the bad parts I found like gears with the broken teeth and shifter fork.)

So tonight I finished coating everything and got the parts out of the upper case. The chain guide I found was in one piece when I took it out but as I laid it down for the picture, you can see it split into 2 pieces. There was a crack in it and it just fell apart in my hand.

I am getting all the nessisary rebuild kits from Chacal but I can't seem to find that guide anywhere? (most likely because I don't know what it is called outside of it being a guide)

On top of that I have a question about bearings. Is it possible to "rejuvenate" bearings I am pulling out of the internal engine? I am talking about the ones that are on the end of gear shafts, around the starter clutch, etc.?
Sorry if my terminology is confusing or incorrect, I am learning as the days go by.
The bearings I am talking about are ones without rubber seals (something you would find on a wheel bearing) on both sides but the ones where I can see the balls and the other ones that have the little rods.

A lot of the parts I am pulling out of my original case obviously are covered in oil but are very grimy and I can feel dirt or whatever on them (probably metal shards from the broken parts). I believe I can clean a lot of the solid pieces like gears, shafts, etc. but not sure how to deal with the bearings.
Is it as simple as washing all the parts with mineral spirits or whatnot and re-lubricating them?

 

You can't rejuvinate bearings. If they are smooth, and have no gouges you can re-use them though (after confirming clearances with plastigauge during a dry fit-up).

Here is the tricky bit: you have to figure out which bearings you need to match the replacement cases to the crankshaft. You can't just swap the cases or you'll not have the correct clearances to maintain an oil film at the crankshaft journals, and you should avoid just swapping one half of a set of cases since the halves were machined as a pair when new (it can be done, but takes a bit more work as you will have to measure the bearing journals in the replaement case-half and do a fair amount of math since Yamaha only gives us colors for bearing sizes, and not actual measurements).

The bearings are color-coded (you'll see a bit of paint on one of the side edges), the crankshaft end has a set of numbers on it, and the upper case has another set engraved into it (location varies, but usually near the output shaft). Together these numbers let you determine what bearings you already have, and which ones you will need (There is a writeup on this in the XJ4Ever catalog).

Here's the real issue: Finding bearings at a reasonable cost if you happen to be unlucky and not already have what you need. 10 bearings at around $20- $30 each (if you can find them in the colors you need) is going to be spendy (assuming that you need all 10). I went through that process last year, and got lucky; I was able to use a mix of the bearings in the replacement case, and the bearings in the damaged case that I already had.

Here is what I would do.

Take the lower case to your local machine shop and have the crack welded shut (thoroughly clean and degrease the case and the crack yourself to reduce the cost of the repair). It should cost you around $100, and the estimate will be free.
I would have used this option myself, but I was extremely cash-poor at the time, and found a set of used cases for $40 shipped (hugely lucky; did I mention how lucky I was?)

The bearings might be OK. Flush them out with the solvent of your choice WITHOUT letting the bearings spin. Use a light oil to lubricate them, and then rotate them slowly by hand. If any bearing is not buttery smooth, then chuck it and buy a brand-new one (there is one bearing that is nto available new from Yamaha (I forget which one it is), but a bearing supplier might be able to make you one if they have a decent amont of stock on hand; just take it in t them), otherwise you'll need a good used one.

 

Good thing you found out about that chain guide NOW, rather than later!

Here they are:

HCP7551 OEM starter primary chain plastic GUIDE, for all XJ650, XJ700, XJ750, and XJ900RK, RL, N/FN, and F models. NOTE: some original versions of this guide used three mounting bolt "tabs" (and required 3 mounting bolts). This replacement versions only uses two mounting tabs, and thus two mounting bolts (one at each end).
$

HCP4791 OEM starter primary chain plastic guide RETAINING BOLT, use 3 per guide, for all XJ550, FJ600, XJ650, XJ700, XJ750, and XJ900RK, RL, N/FN, and F models. NOTE: some original versions of the guide may have had three mounting bolt "tabs" (and required 3 mounting bolts). The replacement HCP7551 Guide only uses two mounting tabs, and thus only two of these mounting bolts are required. Each:
$

HCP10233 OEM starter chain and guide oil spray nozzle O-RING, use 1 per engine an all XJ650, XJ700, XJ750, and all XJ900RK, RL, N/FN, and F engines.
$

 

Alright I need to step back because I think my terminology screwing up what I am understanding.
I have two complete upper and lower cases. The dirty one is the original and the painted one is "new".


This is the crack I was talking about and I don't know where the missing piece is (not sure if that could be welded anyway)


Next, when I am asking about bearings I am talking about these.

These are the same bearing that came from inside of the Upper Cases.
The top one is from the "new" and the bottom is the original.
I believe this on the end of the Stater Clutch. It came from here.

I was asking if these bearing are able to be cleaned and "re-juvinated". The bottom one has a ton of dirt in it.

Next I have pictures of the Crankshaft # (21222 1212 is what I read, picture is hard to see)

 

Pictures of the scratching on the outside of the cases.

Original Case (7345 56545 40 46, is what I think I read, sorry it is upside down)


Newer Case (5227 45666 45 40, this is harder to read)

 

The Crankshaft Bearings. 4 sets of them have the #1J12D , 1 set has #1J09A

I can not find the "color" on any of them.

But if my math is correct I have this [parenthesis is the case number backwards]
Original Case with Crankshaft
21222-(54565)=33343

New Case with Crankshaft
21222-(66654)=45432

So would that mean I need a "Black", "Green" and "Yellow" bearing set?

 

Now on to the Starter Clutch. How do I get these Allen Screws out to replace the springs and rollers?
You can see in the second picture that the backside of the screw has been hit with a punch so that I can't unscrew them?


Oil Spray Nozzle? It looks like a very small pin broke off of this? Does this need to be replaced?


Finally just wanted to show you all the gears that were in the Original Case and the ones I purchased to replace them with
Original (Broken Teeth)

Newer Set

 

I think that we are both clear on the terminology, and all of my prior answers (but one) remain the same.

The crack can be welded, and the missing peice built up from weld and re-machined (this will increase the cost, so using replacement cases is now the better option uness you have a friedn who welds aluminum and will do the machine work in exchange for beer).

Your math for the plain bearings looks correct, and your assssment of which bearings you need is correct as well. The color marks are difficult to see, and often are faded (see photo below). Keep in mind that there will have been some wear to the plain bearings, so you will still want to confirm clearances with Plastigauge before final assembly of the engine.


The color marks look like this; note the black strip of paint on the long edge of the shell.


Your oil spray nozzle looks to be undamaged. You should replace the o-ring though.

 

You can unscrew the allen bolts. The staking applies just enough distortion to keep the screws from backing out. You'll need to secure the clutch body in a soft-jawed vice and use a cheater bar on your allen key if you don't have a set of allen sockets.


And the new gears look really good. Have a close look at the 2nd gear engagement dogs for rounding at the edges. If there is any we can link to the fix for that. Save the old gears for later use (the bad ones can make nice paperweights). The good ones might come in handy some day.

 

The locating pin (that keeps the oil exit nozzle pointed towards the chain) is broken/missing. It's nothing more than a small dowel pin, but it needs to be there. Perhaps you can drill it out and re-fit a generic hardware store pin.............

Yes to replacing the o-ring.

 

Oh crap. I did miss that.
I think that an easier method would be to use a bearing retaining compound on the nozzle, just outboard of the o-ring. That would hold it in the correct orientation and still allow for later removal.

 

Little bit of an update with a question attached

So I am working on putting all my covers back together since I had to dismantle them for powder coating. I also dismantled my Starter Motor and used this thread to put it back together http://xjbikes.com/forums/threads/replacing-your-starter-motor-brushes-w-pics.45727/.

After I got though it all I had these pieces left over.


I also used this diagram in the process to make sure I had everything but I don't see where they go.

I thought the washer on the right was #13 in the diagram but it is larger than any part it seems to sit around? Not sure if I accidentally put them in the bag when I was taking the motor apart or what. That thread doesn't show them anywhere either. But after I reassembled it, it seems to spin fine so I am just asking to make sure. I might need to take it apart again to show with more pictures but wasn't sure if anyone would be able to tell me right away.

Also finding any sort of diagrams on the covers themselves seems to be difficult, like the clutch cover or the alternator cover. I had to locate images online to figure out which direction this went back on.

Which speaking of, you can see the lower (I believe it is graphite) piece is broken off. Don't know what part that is and if you can get a replacement for it or if I would need to replace the whole thing?

Any help is always appreciated.
I got my first order from Chacal of a ton of rebuild parts, Gaskets, O-Ring, Hardware set, etc. Also got Springs and Rollers for the Starter Clutch which is my next project this week.
More pictures of my process to come. Going to see confirm clearances with Plastigauge on my new bearing shells too to double check my math from above.

 

Cleaned up and rebuilt my Starter Clutch with new Springs, Caps and Rollers. Can definitely tell a difference on how those rollers spring back compared to what was in there.


Also cleaned up my Middle Driven Gear and Damper (again, hope the terminology is correct).
I went to place that into the upper case to see if it fit and when I have that middle gear shim next to the bearing, it doesn't seem to fit? So I am wondering if the shim I have doesn't fit my new upper case, reason being is because of this quote from how I determined my Crankshaft bearing journal sizes.

" 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"

Talking about this shim


Maybe I am wrong but when I try and fit it without the shim it slides in fine. So I don't know if my current shim is too thick or if it is just difficult to get in there. The Retainer plate with the Torx screws I never took off so I thought if I loosened that I could get it to sit correctly and then tighten the Torx screws back to make it snug?

Outside of that, everything is going well. All my other parts are clean and ready to place once I double check my clearances for the crankshaft and the new bearings. Once that is good to go, I can put the cases together and move on to the top half.

Next is cleaning Final Drive and Front Brake, reassembling Forks, powder coating Swing Arm. After that I can start "putting the frame back together" to get a overall picture and start mapping out brackets and tabs for new lights, seat, ignition, battery, etc.

Still could use help on above post too.

 

Your current middle drive shim may be too thick. The assembly should slide into place without difficulty, and without ANY slop, but you MUST remove the bearing retainer plate in order to fit everything up correctly.

 

When you go to seal the case halves, I reccomend using Locktite 516 or 518 in place of Yamabond or Threebond. It's much easier to work with and very forgiving of sloppiness. Any squeeseout will mix with the oil and not do any harm.

 

Next,

Was putting my forks back together and was wondering what this was about.
When I took them apart, the spring came out with the tighter coil pointing down (which the manual says have it pointing up and then the hollow metal tube/spacer (highlighted in Green) that was in there.

But I don't see if on the diagram..? Is this something the previous owner could have done and if so, why?

 

You are looking at the manual for the 650 G and H. Your 82 is a J and the forks are a little different. It is correct, I just rebuilt mine.

 

Excellent! Thanks. Where is that diagram from, I don't seem to have that image in either of the two manuals I have?

 

There is a supplement manual for the J (82) model that covers the differences in the suspension, electrical, and YICS motor among other things. I recommend you get a copy with as far as you have it torn down. I have a PDF, PM me and I can figure out how to get it to you.

 

Today I fit my cases together with my new journal bearings and used the plastigauge to check tolerances.
The Manual calls for for 210 in-lb (or 17.5 ft-lb) of torque on the (10)8mm bolts that go around the Crankshaft. My Torque Wrench could only do 200 in-lb.
The oil clearance asks for 0.040mm~0.064mm.
Attached are the some pictures of me setting up. The circled numbers are the new bearings I purchased along with the ones I took from my old case.

 

You are doing things exactly in the right way, congrats!

 

Put everything together and tighten it all down (I only used the 10 bolts that sat around the Crankshaft, not all 39 required for the whole case)
I tired to get the best pictures I could of each clearance, starting from Left to Right.


Part of me is unsure if I have them sitting in the right spot, with the markings on the case and from the Crankshaft itself and then have to spin one of them backwards to figure out what each one needs, there is a slim chance they are in 12345 when they should be 54321?

Besides that, visually the clearances seem pretty good. #4 was the largest but wasn't as wide as the .038 measurement (meaning it is under 0.040mm)
#5 being the smallest.

I have three more "3" bearings from my old case, so I am wondering if I should swap out the 2 for a 3?

Besides that, I think I am ready to assemble the cases back together next weekend and get moving forward.
Any thoughts?

 

Calipers
Anyone have an idea how I can un-cease the piston?
Or a good way to pull it out.

 

Grease gun on the bleeder screw, block-off plug in the union bolt hole, squeeze the handle and it pop!

 

Just, uh, put a block of wood or something on top of the piston. Those become freakin' missiles.

 

Not with a grease gun it doesn't. It becomes a missile with an air gun. Grease doesn't compress and force out via uncontrollable expansion. It forces out by hydraulic pressure, and loses its pressure instantly every time the piston move the tiniest bit. It will slowly force the piston out. The extra thing you need to do is clean up the grease.

 

Was putting my cases together today and a lot of the bolts I had from the cases don't seem to match up with the numbers from this thread
http://xjbikes.com/forums/threads/xj750-engine-removal-and-split-pictures.38545/

Is there any other link of what bolts that go to which hole. The manual doesn't list them, just the Thread Size, not the length?

 

Also 11-17 is listed as 8mm but I think they are 6mm?

 

I'm afraid that you'll have to do some measuring to figure that out. TO the best of my knowledge all of us on here make a cardboard template to put the bolts into as we tear the engine down.
Here's how I tackle the process of finding out the depth of a blind hole. Take a length of stainless wire, or of a wire coat hanger. Put it down the hole and mark it wih a sharpie, then remove and match the marked length to the closest lenght of bolt that size. The sharpie can be wiped off with brake cleaner when you move to a different depth of hole.

 

The Yamaha crankcase fastener system is a "can-o-worms" because there are two different numbering "systems" for the various fasteners:

- in the service manual, which has the fasteners numbered IN ORDER OF LOOSENING (AND THEN DURING ASSEMBLY, THE ORDER OF TIGHTENING). Thus each and every fastener position has a unique ID number.

- in the parts diagrams, the bolt fastener positions are given ID numbers based on their SIZE, thus multiple bolt hole positions can (and do) use the same size fastener, and thus carry the same " ID number".

The numbers that are cast into the engine cases (in some positions) are the unique position numbers and correspond to the numbers in the service manuals (i.e. the order of loosening or tightening). These numbers, ALTHOUGH SOME OF THEM "OVERLAP" WITH THE POSITION NUMBERS IN THE PARTS MANUALS, have nothing to do with each other and should never be confused!

The "use at" numbers listed below are the PARTS MANUAL POSITION NUMBERS, and thus are not what is cast into the crankcase, nor what are listed in the service manual diagrams.

And finally, the position ID numbers in the PARTS MANUALS differ between various engines; what is listed below is correct for Devin's 1982-83 XJ650 MAXIM model, but may (or may not) be the same for other XJ650 models, years, or for any other engine size, even though there will, in fact, many of the same size fasteners used on other engines.



*HCP15951
OEM crankcase upper-to-lower retaining BOLT
use at: position 25 (2 per engine)
size: m6 x 55mm


*HCP15952
OEM crankcase upper-to-lower retaining BOLT
use at: position 27 (3 per engine)
size: m6 x 35mm


HCP15945
OEM crankcase upper-to-lower retaining BOLT
use at: position 17 (use 10 per engine)
size: m8 x 105mm


*HCP15946
OEM crankcase upper-to-lower retaining BOLT
use at: position 19 (use 2 per engine)
size: m8 x 65mm


HCP15947
OEM crankcase upper-to-lower retaining BOLT
use at: position 20 (use 2 per engine)
size: m6 x 120mm


HCP15948
OEM crankcase upper-to-lower retaining BOLT
use at: position 22 (use 3 per engine)
size: m6 x 80mm


HCP15949
OEM crankcase upper-to-lower retaining BOLT
use at: position 23 (use 3 per engine)
size: m6 x 70mm


*HCP15951
OEM crankcase upper-to-lower retaining BOLT
use at: position 25 (use 2 per engine)
size: m6 x 55mm


*HCP12786
OEM crankcase mounting BOLT
use at: position 26 (use 7 per engine)
size: m8 x 45mm


*HCP15952
OEM crankcase upper-to-lower retaining BOLT
use at: position 27 (use 3 per engine)
size: m6 x 35mm


Although all of the above is screwy (but, at least it's semi-logical "different diagrams for different purposes" point of view), there's just no getting around the other more interesting aspect of rebuilding these engines: bearing sizes: compare scrawled on engine case vs. cast on crankshaft numbers, subtract A from B, the sum is the bearing "color" code, which is a surrogate for the bearing thickness. Now, measure your bearing clearances with plastigauge. If the cleanance is out of spec (let's say, too big of a clearance, or "loose") then what replacement "color" (size) bearing should you use?

Good luck on answering that question!

 

Hey guys, back for an update. Got the Flu and was down and out for a bit.

I ended up doing what K-Moe suggested and just measuring each hole and have some different numbers than what Chacal has listed above. Having trouble finding bolts at local hardware stores for really anything over 55mm, especially the longer ones.

But outside of that I got the Crankcase together. Not sure if I mentioned but I remeasured all bearing journals with Plastigauge again and had much better results.
I used Loctite 518.
After a weeks or so the "Squeeze Out" is still wet, is that normal??

Everything feels like it is moving smoothly, the shifter forks move freely and all the gears spin fine! So I think I am good there.
One I get the hardware complete for the crankcase, on to the rest of the assembly.

In the meantime, got some fresh tires and started putting it back together to start figuring out Lights, Fenders, Etc.

Here is what she looks like

 

Loctite 518 cures anaerobically. The squezeout will never cure (which is the whole point; no risk of goobers coming loose inside the crankcase and blocking an oil passage. The excess just mixes with the oil). Clean it up with a rag and some carb cleaner or mineral spirits.

 

I'm liking the looks of your progress, very nice neat work.

 

Hey Chacal.
I see position 25 and 27 are repeated. But according to my parts diagram I need bolts for position 24 and 21?

Am I missing something?