Re: honda cr80 engine
They're big, and make in frame mounting hard and pedal cranks need to be chopper style to clear the case. Those are the main drawbacks, they're awesome though. People are planning stuff with them, just check around and there are builds.
KTM50 Schwinn Chopper - 6000W E-Motard - 52cc Auger BMX - 9sp+CVT 52cc Cagllari Moped