Pre-Motorized Bicycle Information.Before you mount that engine to your bicycle frame, you'll want to know if the bike is ready for the engine! Ask our experts here for advice on what will perform well.
It will fit fairly easily with a shift kit. I have read some people have used as small as a 17". I have built 2 using 21" GT LTS, one of them aluminum LTS with a china girl and shift kit and the other a cromo LTS with a KTM and shift kit. Heres my build link for the KTM....... http://motorbicycling.com/showthread.php?t=46976