noise behind clutch cover

[twalter]

Hi guys. Ya got a newbie here. I have a noise behind the clutch cover of my new-to-me xj. It has a kick starter spline, so I don't think the thermo-dynamic power creator is original. The noise comes and goes like it is a harmonic vibration, but also sounds like a gear grind. It happens at differing rpm around the 3-5k rpm range. The trans shifts fine, and it does not seem to come from the gearbox area. It does not sound like a chain slap. It happens sitting still or in any gear while riding. Do the clutches on these things make noise when the are out of adjustment, or otherwise not happy? Do the kick start gears chatter? I am a good mechanic, and am about to tear into this thing. Any ideas on things to look for would be appriciated.

[TopCatGr58]

Hey TWalter,

There is a serial number stamped into a plate just above the clutch cover on the engine case, you can then use that to look up what model that "Thermodynamic convertor" came from, most likely a 78 or 79, since that's when they still had the kickstarter shafts, they got eliminated in 80. Will also be curious to find out IF you still have all of the proper XJ electronics. A fellow Xsive/XJer has an XJ with a transplanted XS engine, but has all of the XJ goodies, the TCI, the pickup coils/plate, but no vacuum or centrifugal advance mechanisms under the left timing plate cover, also has the newer brush alternator on the right end of the crankshaft, vs. the weaker brushless XS version!

What many folks find for engine noises actually ends up being cracked or broken exhaust welds/joints, or the pipes not securely fastened to the frame and causing harmonic vibrations, so check your pipes first before tearing into the engine!
T.C.

[twalter]

Yes. I have all of the xj electronics (as far as I know.) No vacuum advance. Just 2 pick ups. I am fairly experieced with mecanical noises. I checked it with a steth. It is comming from under the clutch cover. What is under there that could be rattling? Thanks for the quick reply. I apologize ahead of time for slow responce. I am on FREE dial up. The motor number is not of an xj, (10m.......) but some po swapped the shocking stuff.

[T748]

Does the noise go away when you pull in the clutch? My XJ11 had a strange noise behind the cover that ended up being a bearing going bad. This was the littile bearing that sits behind the "clutch activation arm". I'm not sure what Yamaha calls the parts. I'm stuck at work with no manual to look at.
Basically where the clutch cable goes into the motor, theres an arm that the cable pulls on. That arm is connected to a post that is supported by the bearing i'm talking about. it made more noise as i rode it. I kept readjusting the cable thinking that i was mis adjusting it causing the noise. One day the clutch stopped working and i had to open it up only to find most of the balls in the bearing were gone. The replacement bearing was $11. from the dealer.-Tom.

[twalter]

Hey. Thanks. That sounds exactly like what it could be-a bearing about to grenade. Does anyone know where I can get a look at a blow up diagram? Also, I went to take the cover off last night and it is "glued" on with some RTV. Does anyone know of a sovent that will eat this stuff?

[DiverRay]

You can go too the Yamaha web site, and look up the "parts catalog" online. There are diagrams of each section, including the clutch. This will also give you a part number to take with you when looking for the bearing.
As far as the RTV, use a "deadblow" hammer to loosen the cover, and slowly work it off. You can then strip the gasket with acetone, or some like deadly chemical. I would use the non hardening Yamabond and a new gasket when putting it back together.
Ray

[TopCatGr58]

You ain't got the balls??

Hey TWalter,

Here's a view from the parts fiche that Bike Bandit provides for looking up OEM parts for ordering:


The part 24: RETAINER,BALL 22678-001 $7.51 IS still available.

There are 3 ball bearings in it, and the manual states that care needs to be taken when putting the clutch cover on after a repair, to NOT rotate the throwout lever/rod, otherwise it will rotate the bearing holder, but without the clutch starplate throwout bearing to push against, this part can get loose, and the ball bearings can FALL OUT!?

[T748]

On mine it was #14 that went bad. Some of the bearing balls had turned to black dust. In the end it siezed and messed up peice #26. The end of that got stuck in #15 from the friction sticking the two together.I ended up breaking #26 trying to seperate it from #15. -Tom.

[twalter]

The noise is deeper. I got it back together and fired it up. It was on the center stand. Every time I revvved it and heard the noise the rear wheel tried to spin. I pulled the clutch in and i twent away. What would make this trans try to engage when it is in nuetral? Why would it make the same noise in all gears?

[randy]

Not enough oil?

[knewsom]

or a poorly adjusted cable...?

[twalter]

The oil level is right on. If I don't send power to the trans (clutch disengaged) all is normal. When I send power to trans (clutch hooked up) it tries to engage a gear while in neutral, but never fully does. The clutch and trans are working fine when riding so I can't believe it would be a cable adjustment. Shifter fork maybe? Has anyone experienced the rear wheel trying to move with the bike in neutral?

[Geezer]

The rear wheel will turn in netural when running (on the center stand) with all bikes. It's from oil drag on the transmission gears & shafts.

If I were working on it, I'd stop talking about it and tear into it. You're not going to diagnose it from the outside.

Geezer

[twalter]

When the wheel starts turning it isn't a gradual motion like oil, it is a herky jerky thing, like in&out of gear. I don't want to admit that you are right, but you are. I'm flippin it over and pokin' around. It may be a while, but I'll let you know what I find. Thanks a bunch guys.

[Geezer]

While you have the clutch side case off, try moving the clutch basket up and down (and hope it doesn't.)

Sometimes the truth sucks (like when my truck started blowing water out of the raditor last week...)

Geezer