82 XJ650 - primary chain guide woes...

Way back in December I got to trailer my lovely little bike home because she wouldn't shift out of first gear. Clutch still worked perfectly, but the shift lever wouldn't budge upward! I got suffer through public transit for a month. Then I got a (very lovely) 06 FZ6 and rode it through the entire (record setting snow) winter. Funny to have two Yamahas a few decades apart and see how the engineering has changed (or not).

Anyway...

Finally got time to pull the side cover off the XJ after draining the oil. What I found is two large chunks of plastic that aren't quite small enough to pull out of the observation hole. I'm running under the assumption that this must be the dastardly "primary chain guide" that has decided to give up the ghost. I un-wedged the plastic bits from where they were stuck and, lo and behold, was able to operate the shift lever again. Drat, was hoping it would just be a few springs...

I know I am looking at splitting the cases to do this repair. I have two questions I hope the brain trust here can help me out with.

1. What other things should I plan to do or be prepared to do "while I'm in there"? The starter clutch is already on the list.

2. Where are the "gotchas" on this repair - the unobtanium part or thing that will stick me? I believe I have all the tools necessary already, including another bike to ride while I rip this one apart.


Any advice is very welcome so I can start putting together a parts wish list.

 

Be prepared to flush out lots of tiny bits of plastic.

Clean the oil pump pickup screen.

May as well check the oil pump drive gear endplay.

Be very careful removing the chain guide mounting bolts. A little heat will help. The front one (near the crank) sometimes will snap off; if it does take it to a machine shop to have it extracted as it's not going to come out easily.

Use Loctite 515 or 518 to seal the cases. It is much more forgiving than Titebond/Yamabond, ect.

It is a good idea to go ahead and replace the crankshaft seals, as well as the o-rings and seals for the alternator, clutch arm, and shift lever shaft.

Be prepared to see a damaged oil nozzle near the starter. Check it carefully. If it's not worn through then you can replace the o-ring on it and keep it in service.

The actual splitting of the cases can be difficult. Do not use metal tools to pry with. Careful application of a rubber mallet will usually do the job.
Gasket remover spray/liquid is a godsend, because scraping gaskets sucks.

 

Thank you very much, k-moe. I'm going to pull the motor out of the frame next week and give the frame a close inspection. There is some surface rust I've been meaning to take care of... if the rest of it isn't in great condition, I might part the bike out. Besides the engine rebuild, it needs the usual valve shimming, new exhaust, new front brakes (rotors and pads), new brake lines, new or rebuild MC, full carb rebuild, and possibly some electrical work too. Not sure I am ready to tackle that kind of project without a garage to work in.

 

bostonbacon, wow, definitely might need a garage, where in boston are you?

 

Within city limits. I do have a nice long driveway to work in for most things and a room that can be turned over to doing mechanical work here and there. The joys of renting...

 

here is a nice link to your future repair........

XJ750 Engine removal and split - Pictures. | XJBikes - Yamaha XJ Motorcycle Forum

 

That thread should only be used as an overview, and not a guide. Many details were left out for brevity's sake.

 

however, it is the only link that i have seen that had pretty good pictures along the way....i agree, a good overview

 

That's because it is the only thread with the pretty pictures. IT is worth bookmarking.

 

Color pictures are welcome addition to the scratchy black and white manual for sure, thanks for the link.