So I have a buzzing sound/very slight vibration that starts around 3000 rpms and then goes away around 3500. It will do it no matter what gear I'm in and it stops if I pull the clutch in or accelerate out of that range, so I'm thinking it's transmission related. No problems shifting gears or loss of power. The engine has recently been rebuilt but I didn't replace any transmission parts, anyone have any ideas or places I should start?

 

my dad had this issue on his 78' cb750. turned out to be a bearing that was shot.
on the rebuild, did you, or whoever rebuilt it, remove any bearings from any of the shafts and re-install them?
if a bearing is bad, unfortunately that means your engine would have to come back apart and have new bearing(s) installed.

 

I know this thread is old but I want to bump/hijack it instead of creating a new one, consolidation you know, and beacsuse I have the exact same issue, I have a buzzing noise while I'm on the throttle regardless of how hard I'm on it and it immediately stops when I pull in the clutch or let off the gas, I would imagine that if it's a bearing it would be making a noise all the time including at idle which mine does not, any suggestions?