XJ600 Diversion gears slipping and metal rattling noise?

[overhage]

It started yesterday, when I let off the throttle on my Diversion I heard a strange light rattling noise that seems to be coming from the left side of the engine (not the right, the side of the clutch), as if some metal pieces were flying around in the crankcase. It started with just that noise, when I was accelerating there was no noise and no problem, but then later during the day I was driving around 70mph (120kmh) when I suddenly let off the gas and it felt as if the bike slipped through its 5th or 6th gear. I carried on an it got worse, when I hit the city and went off the motorway it happened also when letting off the throttle in 1st, 2nd and 3rd gear at low speed... And to make things worse, my gears now also seem to slip when accelerating!!

As the noise seems to be coming from the left side of the engine, I had a look at the front spront and took off the case as well as the case of the alternator. Nothing, all looks normal. 

Has anyone ever had this problem? I don't think it's one of the shifting forks as it happens in all gears (the noise seems less or gone when clutch is in or accelerating) plus I can't imagine suddenly all gears are worn... Could it be the primary gear on the clutch basket that drives the gearbox?

[hughmcq]

I once had something similar and was advised on here to check the rear wheel bearing. I know its a long way from the engine but sure enough that was the problem.....

[overhage]

Thanks for the reply, I can imagine that you say rear wheel bearing because of the rattling noise, but I don't think it's a bearing in my case... The bike is clearly losing power when it slips through its gear(s) and it vibrates / shocks heavily...

Anyone? Could it be the primary drive on the clutch basket or is my completely gearbox f*cked? My bike has only done 30k miles so I can't imagine it's the end of its gearbox already...

[bobh]

If it's the left-hand side it sounds very much like a problem somewhere in the final drive area - chain (condition, tension), sprocket (worn, loose on splined shaft), rear sprocket (loose, worn), cush drive or bearing (wear, too much play).

It might also be a bearing in the rear rear wheel that's starting to break up. This can happen even if there's no obvious sign of play.

Good luck in diagnosing it.

[brianpb]

When you say the bike is clearly losing power do you mean the engine is losing power or the power is being lost through mechanical slippage?

It is not impossible for a gearbox to give up after 30k miles, unusual yes but it does happen.

Personally, unless you are capable of stripping and fixing it yourself, I would get it transported to a trusted repairer and get it diagnosed properly.

If there are bits of gearbox floating around consider an engine swap, you will never be certain that ALL the bits have been removed if you just fix the gearbox and odd bits of metal floating around the engine are not recommended!

[HRHpenfold]

Sounds to me that the chain is jumping the front sprocket.