not too mention coming up with a decent charging system and seriously, whats wrong with using the clutch like everyone else?
you need a motor, as previously stated.
you need a one way clutch, or freewheel, unless you intend on using the same motor as the generator.
you would need a fairly hefty switch, or to wire up a solenoid/relay.
you would need a battery.
you would need a machine shop or pockets deep enough to warrant the whole project pointless and just get an engine with Estart.
you know the motors strong enough when it can break your thumb and still pull 1000rpm. think cordless drill in low gear.
what chain and sprocket will you attach it to? the one that goes to the wheel? theres a clutch that separates that part from the engine itself
usually, by the time people get this far...they dispose of the petrol engine altogether and call it an E-bike