Bonneville America Forums Forums Technical Forums General Tech Oh Bugger...

A couple o weeks ago my 4 month old heavy duty chain snapped under acceleration, looks like a small stone got in there. The chain bunched up under the front sprocket cover, smashed all but one o the bolt holes and knocked a hole in the gear change mech cover.... I'm pretty sure I managed to recover all the wee ally bits. Fixed the gear mech cover no problem, refitted, fresh oil so I could fire the engine to make sure it was ok. Engine fired no problem with no chain but there's a helluva nasty knocking sound coming from the clutch side and can be felt through the case and front sprocket. As the engine heats up the noise will go away but only with the clutch lever pulled in.
So I'm looking for ideas or notions o what I'm looking at here. Apart from the knocking noise the motor runs fine so whatever it is it doesn't seem to be interfering with the running.
My thoughts are possibly play in the countershaft which is normally taken up by load from having a chain fitted.
Cam chain tension out caused by the strain when the chain snapped.
A wayward bit o metal from the broken case.
Or a hundred other expensive things?
Depressed as hell at the thought of it being stuck in the garage instead of out on the road.....
HAYULP!

I was running the bike on the stand one day (checking my chain alignment) and it made a help a racket but not while riding.
My only idea is to put a chain on and see how she sounds and feels.

I'd remove the cover and look at the sprocket and shaft to make sure you didn't bend anything. You could put a piece of wood against the sprocket to put a load on it when running to see if the noise goes away. Seeing as the noise goes away when you pull the clutch in(which means the shaft stops spinning) you may have damaged a gear tooth. I wouldn't run it until you find out exactly what it is.

Could be a broken clutch spring. Best investigate further before you ride it.

Investigated today, found a small piece o the gear mech case in the oil strainer but that wasn't the culprit. Traced it to the clutch, springs are good. It's possible there's another bit o broken case in the clutch somewhere but that's for tomorrow.

Hey Ron,

Sorry to hear about the bad bit of luck.

Make sure you don't misplace the starter idler gear wavy washer when you reinstall the clutch cover or you could have another problem to address.

Keep us posted on what you find.....

So... not the clutch then. Looks like it could be a bent or broken gear selector fork as I can get 1st, 2nd then it jumps to 5th... So it's out with the engine which is something I was looking to avoid. Ah well....

Ron,

Before you pull the engine, you stated that the gear change cover was damaged. Were you talking about the cover right under the drive sprocket? If so, that houses the gear selector mechanism. Pull that cover and check to see if everything is ok. I've never had mine apart but I wonder if something could have been knocked out of kilter or time?. The main shaft (gear change) that runs through to the other side of the engine can be replaced without pulling the engine if it is bent.