FOR PARTS:
www.rollingwrenchdenver.com
Belt video:
What size scooter belt do I need https://youtu.be/c3Sw0l6iSZk
If you are confused what engine you have in your machine, this video should help.
QMB139 = 50cc air cooled 39mm piston (made in China) 52mm is the max big bore kit size
QMI152 = 125cc air cooled 52mm piston (made in China with 54MM stud spacing or made in Taiwan 57mm stud spacing) 64mm max case bore size (A motor) 70mm max case bore size (B motor)
QMJ157 = 150cc air cooled 57mm piston size (made in China with 54MM stud spacing or made in Taiwan 57mm stud spacing) 64mm max case bore size (A motor) 70mm max case bore size (B motor)