Hi there! I noticed I'm a little late in the game! (since this engine on a bicycle seems to be around since the 1970's). Recently I discovered my love for 2 wheel balancing, and bought an electric moped. I was pretty happy with it, but soon figured out I needed more (as it was only doing 23MPH). I bought a 50cc scooter, which was tuned insanely, and got speeds of upto 50MPH out of it (with a little tail wind). I love my scoot! It's a problem-less scoot for ~2,5k miles, and I get 99MPG out of it on average (a TaoTao ATM50). But a forum member posted on these bicycle with engines, and when the number 150MPG fell, I was intrigued. (who wouldn't want to scoot around a whole day for less than $5? I looked at the 3 motor options, and the one that speaks most to me, is the 2 stroke motor, built in the center of a cruiser bike frame, with chain. In my other threads you will see which one. I hope to find the right bike, motor, and stuff for what I need! Thanks!