Hello MV,
I have a high pitched whine coming from the left side on acceleration. It stops when I back off the throttle. Above 50, it either stops or I can't hear it over the engine noise.
Through searching the forum I've found some possible causes: Intake air leak, dampening ring, bearing on belt pulley or low gear oil.
Gear oil is fresh and at the bottom mark of the dipstick. I looked over every inch of the intake and see no cracks, holes or problems.
Scooter has new Piaggio belt and Dr. Pulley sliders. I also replace the clutch bearing in the CVT cover.
I'll pull the variator and replace the ring and belt pulley bearing since these parts are cheap enough.
Anyone run into this and solved it? Thanks in advance.