I've had this annoying buzzing noise on my bike for quite awhile.
Finally have figured it out to be the chrome pulley cover.

Mostly, if at all at idle, a buzzing sound from the back end. When I let
the clutch out at neutral it recedes a bit, but still there. When I push
on the rear pulley cover, it stops. Bolts are all tight, can't find anything
else loose. I'm thinking it's the cover, which is driving me nuts.

Anyone else have this? I'm thinking of pulling it off and maybe using a
light automotive seal. That or just getting a new pulley..