i am looking to start a tom thumb minibike from the popular mechanics:way: i had a few questions:
1. what motor should i use that is semi cheap
2.what type of tubing should i use
3.do i really need a jackshaft
thatnks

1. Not the POS I used......I think a two stroke industrail engine would be good, a
large chainsaw, Tecumseh snow blower engine, or anything else you could find. Four stroke would work too, but not as good. If you can find a suitable 50cc dirt bike or atv engine that might work too.
2. I used sch40, 1/2" pipe which worked fine. I could probably go down on the wall thickness, but it still weighs close to nothing.
3. Depends on what engine you get, what clutch you get, where you will be riding, total weight, and rear tire dia. In most cases I would say you will need one. They aren't very tough to incorporate anyhow.