I did some simple modifications on my Kymco Agility City 50cc, And after i change drivebelt theres a humming/vibrating sound from variator both front and rear. it starts after 45kmh and is strongest/most distubing downhills 50-70kmh.
i recently change new drivebelt and this problem started then.
The scooter is as fast at before but not comfortable higher speeds and downhill.
I also notiched a wear om the outer core of the new belt?
