It's funny that this topic came up just now...

I've been thinking of doing a small motor on a mountain bike type frame, but haven't spoken to anybody who's done it. I just wanted to chat with someone who did it... just to get some practical insight.

Two days ago, I stopped at the grocery store on the way home to pick up a few things, and parked in front was a cheap mountain bike with one of those little two-stroke motors on it! As I stood there looking the thing over, the owner came out and we started talking.

To make a long story short... he's an engineer-type nerd like me... and he made some changes and tweaks to the system. He has this thing going at a top speed of about 45MPH (he mounted a disc brake suspension fork for safety) and it's getting almost 280 MPG!!

I know the emissions of the two-stroke are worse than its 4-stroke bretheren, but hell's bells... how bad could the emissions be for a vehicle that's getting 280 miles on a single gallon? I'd venture to say that it puts out waaaay less than ANY conventional auotmobile on the road.