Re: 50cc GY6 on a Bicycle??
That's a good idea L2!
The pivot might could be mounted thru pivot point on a rear suspension bike, though pedal interference might be an issue. The weight of the unit would probably be sufficient to offer positive drive. On a rigid frame bike it could be bracketed in the rear axle area, or a rig could be made to attach to both sides of the axle as a form of push trailer. Hook up would be as simple as a throttle cable, fuel line and basic wiring. Mount a battery to the unit and you have electric start/charging/lighting.
Pretty cool idea! at around $250-300 its no bank breaker, and the 49cc version should be legal for most.