Hi all i have a totaly standard mc21, and i've just started to notice a strange noise coming from behind clutch cover, i've drained oil and it was nice and clean no filings, it seem to be worse when choke was on than when the choke is turned off, i had to listen for the noise allot harder, seems to be more on tick over if revs picked up the noise seems to go away, i know a noise is virtually impossible to sort without hearing it, it doesn't go away when clutch pulled, any idea's is there a bearing thats prone to go or a bush, im assuming its not a bush because of the lack of filings in gearbox oil, its got 5k on the clock i think the milage maybe genuine as it has the original chain and fairings are unmarked and engine sounds sweet apart from this noise, i've owned it 2years and had no noise when i got it.

It might help if you described the noise: ticking? thumping? whistling?

Related to engine speed or road speed?

Hi yea sorry it best described as a rumble, so would say it's a bearing
But why would it be worse when choke was left on?
But like I say it seems to disappear when at 1500rpm ish
So again would say it's a bearing, is there a bearing that's prone to go?

Pretty hard to know what to say here.
You really need to pull the clutch cover off and look into it properly.
The fact that it doesn't go away when you pull the clutch in makes me think it might be the right hand main bearing on the crankshaft, or maybe something to do with the water pump?
As for the noise being worse with the choke on,.. I have no idea at all about that sorry.
It is hard to be much help on this one.
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