I'm going the two stroke gasoline route on one of my Schwinn Stingrays like my blue one in this picture.
The engine is a 66cc unit which is attached to a custom made engine mount that was added to the Schwinn frame.
The rear sprocket was a rig-job from square one that was fastened to the spokes with thin plates and junk rubber pads, so I did a redesign on it to make it more durable.
Now the final drive is sent thru the rear hub with a precisely fit collar I machined for it:
No more runout or broken spokes this way.
The front brakes were insufficient for stopping it, so that got a rework too.
That was the largest bicycle disc rotor available, so that is what it gets.
The final drive from the engine to the rear sprocket runs thru a jackshaft after inputting the torque thru a
Shimano 3 speed planetary rear hub to give it a transmission.
That shaft includes another smaller disc rotor to handle the rear stopper.
The jackshaft arrangement will allow me to make gearing changes on it without a major overhaul to the rest of the machine.
I machined a log manifold for 5 whippit nitrous oxide cylinders to feed it tiny shots of NOS when the power is needed.
The engine was also refitted with a reed intake valve to reduce reversion and increase the performance.
I relieved the porting in the cylinder and altered the intake charge timing as well.
A new cylinder head has been designed that will allow me to optimize the compression ratio.
In the end, I hope to get it to travel at around 50 miles per hour on the flats but also pull out quicker with the added lower gearing.
I will retain the pedals so it will qualify as a unregistered moped.
The engine is marked as a 50cc and other than a teardown for measurement it will go unnoticed by the authorities