I want to attach the weed eater that I finally got running to my old mountain bike. I need to know how to convert the high rpm's to more torque. I was thinking that maybe put a propeller on it or directly to the back tire. Need some ideas. Thanks

Here are some clips of both ideas: YouTube - Homemade weedwhacker motorcycle
YouTube - Bicycle with weed wacker engine and propeller

I know a guy that put one on a bike and instead of using gas to power it he uses rubbing alcohol and 2 cycle engine oil. It must work cause that thing flies. He hit 65 on the high way. And it picks up pretty quick too.

Hey John, did you notice that the bigC posted this question a year and a half ago and nobody answer until today? I think big is gone and no longer monitors this qiestion.

My idea wouldn't be hard just switch the gears around or rig up a chain where the engine is spining a small gear on a chain to a big gear.