4g trans

TOTALLY new to this but want to build my first motorized bike. Picked up a nice Genesis Astra 7 speed bike at Walmart for $139 on sale. Solid AL bike with space for a 4 stroke. Read online that I should cut some conduit to use behind engine clamps during mounting to spread the load of the...

i noticed helio has 100t pulley for 4g. if i get it where can i find belts? can i get them from auto parts store?