This looks like so much fun I went and bought a 66cc (fake 80cc) frame mount kit. Sad to say, the bike I was thinking of using just isn't suitable. It's a mountain bike with rear suspension that takes up all the room where the engine needs to go. I guess I'll be looking on craigslist for a sturdy donor bike. No worries about fitting the kit. My main concern is how well this will work without a gearbox for hills. Answers to come soon.....