Quote:
Originally Posted by Maddog
It might be worth changing the trans oil. If there is a problem in the trans the oil will likely tell through metal fragments or discoloration. It's only a few ounces of oil and a needed service. I've never seen trans failure under normal conditions, they are usually the last thing on a scooter to fail.
The clutch drum has some bearings and sliding / spiraled, rotating surfaces that might cause a chatter. Check to ensure your belt is an EXACT match to the OE part.
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This would be a good start for checking. But a clutch will not make much noise if the engine is off and the bike is up on the center stand. If one spins the wheel, the only things turning will be the clutch bell and the final drive gears, bearings and axle.
The engine needs to be spinning to drive the belt which turns the part of the clutch that engages the clutch bell....which turns the gears and rear wheel axle.
So if there is a substantial noise when turning the rear wheel, in both cases of engine off or on, that would lead me to think there is something going on with the gears or bearings in the transmission or rear wheel axle.
If there is some wobble of the rear wheel then this may point to axle bearing failing, but even so, rear axle bearing beginning to fail will not always cause rear wheel wobble. Still, it could be pointing more to the gears themselves or the bearings they ride on.
Another possibility for rear wheel noise is brake dragging, but this might not make a lot of noise.
Chatter on acceleration could be a problem with the variator or the clutch. (chatter would usually be less likely on deceleration)
Is it still noisy while moving along steadily at speed?
Yes? Might be transmission gears or bearings problem.
A problem with the engine would seem to be ruled out by determining that the transmission & clutch area as the general source location of the noise.
Any evidence of excessive oil leaking around the transmission cover, transmission oil fill or drain bolt? any leaks where the shaft comes out for the clutch or where the rear axle comes out of the case?
As Maddog advised, check the transmission oil and note how much comes out upon draining along with color and if any particulate. (there should not be any metallic grit) It should be reasonably close to the recommended amount advised for refill; maybe dark brown but not black.
Black? really old, used for too long unchanged oil or from being overheated too much. (or a combination of)