954 sporadic idle clunk?
Discussion
Video needs the sound un-muting.
When idling at operating temp I'm getting a clunk from the engine every now and then, like once a minute perhaps. This was a fairly quiet one but there's been one occasion it was bad enough to stall the bike, anyone had similar?
Valve clearances and throttle sync have both been adjusted, bike runs sweet the rest of the time this is only when idling. I've read various possibilities from throttle bodies at fault to CCT to clutch basket so I'm at a loss where to start 🤷
I've had a few suggestions of it being the clutch from elsewhere so it seems a likely culprit, but what might the actual problem be? Is it play in the plates or basket perhaps, or just cable tension or something?
For reference I've just had the engine out of this bike to replace a burnt out exhaust valve, it looked like this a few weeks ago
But it runs and rides so well once in gear I'm struggling to believe it's anything to do with the work I've carried out, so erring towards suspecting a different problem that was there before I got the bike.
I'll try a few different combinations of clutch in while idling in neutral and in gear and see if it still makes the noise, I'll report back with my findings.
For reference I've just had the engine out of this bike to replace a burnt out exhaust valve, it looked like this a few weeks ago
But it runs and rides so well once in gear I'm struggling to believe it's anything to do with the work I've carried out, so erring towards suspecting a different problem that was there before I got the bike.
I'll try a few different combinations of clutch in while idling in neutral and in gear and see if it still makes the noise, I'll report back with my findings.
Condi said:
The cam chain guides are a known issue from memory, if one has moved or become disintegrated could that be enough to stall the bike? Guess so if it tried to wrap itself round a sprocket.
I had a good look at the chains, guides and tensioners while the engine was apart and couldn't see any obvious issues, plus i think if it was chain or timing related it would be problematic all the time when riding, not just at idle in neutral?Have you tested the injectors ? If you've got one that's partially blocked it might work sufficiently well at higher pulse width but not when idling when it's being asked to open for just a very small amount of time. Or one might be leaking which doesn't affect higher speed but will at idle.
I'm not sure how a clutch could cause it to stall when it's idling in neutral, did anybody explain that ? If the bearing was worn the basket would wobble a little bit but you'd hear that - it would be pretty obvious when you pulled the clutch lever in then out, but I still don't see how that would cause it to stall.
I'd get the injectors tested and cleaned and check/change any fuel filters you have, see what's in the tank.
Edited: I've just watched the video, I thought it was just a picture, but that sounds like cam chain to me, a little slap. If the tensioner is oil fed I'd swap it out for a new one and see it it improves, or adjust to if it's manual. It might just be harder to hear at higher engine speed.
I'm not sure how a clutch could cause it to stall when it's idling in neutral, did anybody explain that ? If the bearing was worn the basket would wobble a little bit but you'd hear that - it would be pretty obvious when you pulled the clutch lever in then out, but I still don't see how that would cause it to stall.
I'd get the injectors tested and cleaned and check/change any fuel filters you have, see what's in the tank.
Edited: I've just watched the video, I thought it was just a picture, but that sounds like cam chain to me, a little slap. If the tensioner is oil fed I'd swap it out for a new one and see it it improves, or adjust to if it's manual. It might just be harder to hear at higher engine speed.
Edited by SteveKTMer on Monday 31st July 12:41
SteveKTMer said:
Have you tested the injectors ? If you've got one that's partially blocked it might work sufficiently well at higher pulse width but not when idling when it's being asked to open for just a very small amount of time. Or one might be leaking which doesn't affect higher speed but will at idle.
I'm not sure how a clutch could cause it to stall when it's idling in neutral, did anybody explain that ? If the bearing was worn the basket would wobble a little bit but you'd hear that - it would be pretty obvious when you pulled the clutch lever in then out, but I still don't see how that would cause it to stall.
I'd get the injectors tested and cleaned and check/change any fuel filters you have, see what's in the tank.
Edited: I've just watched the video, I thought it was just a picture, but that sounds like cam chain to me, a little slap. If the tensioner is oil fed I'd swap it out for a new one and see it it improves, or adjust to if it's manual. It might just be harder to hear at higher engine speed.
I'm not sure how a clutch could cause it to stall when it's idling in neutral, did anybody explain that ? If the bearing was worn the basket would wobble a little bit but you'd hear that - it would be pretty obvious when you pulled the clutch lever in then out, but I still don't see how that would cause it to stall.
I'd get the injectors tested and cleaned and check/change any fuel filters you have, see what's in the tank.
Edited: I've just watched the video, I thought it was just a picture, but that sounds like cam chain to me, a little slap. If the tensioner is oil fed I'd swap it out for a new one and see it it improves, or adjust to if it's manual. It might just be harder to hear at higher engine speed.
Edited by SteveKTMer on Monday 31st July 12:41
It's definitely a clunk bad enough to cause an engine stumble, if it was doing it on the move I'm sure it'd be immediately noticeable but I only ever notice it on idle so I'm fairly confident it isn't a cam chain issue, however I suppose for the price of a tensioner it wouldn't hurt to replace it.
The injectors are all original and unserviced too.
Just tried holding the clutch in and it still did it once or twice with the clutch held in so I suppose that rules that out.
Darkslider said:
It's definitely a clunk bad enough to cause an engine stumble, if it was doing it on the move I'm sure it'd be immediately noticeable but I only ever notice it on idle so I'm fairly confident it isn't a cam chain issue, however I suppose for the price of a tensioner it wouldn't hurt to replace it.
The injectors are all original and unserviced too.
Just tried holding the clutch in and it still did it once or twice with the clutch held in so I suppose that rules that out.
A quick google suggests the cam chain tensioner is manual, so try adjusting it, details will be in the service manual. It might be doing it when running at higher speed but it's less noticeable then.
If you're not using the bike then I'd send the injectors off to be cleaned and tested too, they can test the spray pattern and make sure they're not leaking.
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