28-07-15, 11:30 AM
It's definitely not the cam chain noise, not a clutch sound (too far forward for that), and not tappets.
If you imagine a rumbling bearing, then take one rumble and make it irregular (about as regular as a tennis ball in a washing machine) then that's about the best I can describe it. Only on load and doesn't matter if it's on a constant throttle opening or increasing opening. I know this is going to be a bugger to pin down. Will try and gleem more info on my 50 mile route home tonight - different gears, revs, speed etc
If you imagine a rumbling bearing, then take one rumble and make it irregular (about as regular as a tennis ball in a washing machine) then that's about the best I can describe it. Only on load and doesn't matter if it's on a constant throttle opening or increasing opening. I know this is going to be a bugger to pin down. Will try and gleem more info on my 50 mile route home tonight - different gears, revs, speed etc
Those are my principles...if you don't like them I have others.