Re: Diesel Engine?
You're going to want to run direct drive without a freewheel mechanism in the diesel drivetrain, probably with a 415H chain because the low end torque at low RPM's is going to hammer the heck out of a bicycle. If you build a beefy one it should be a rock solid commuter though, sounds very interesting. Just something to consider, a pocket bike engine capable of 4-6HP weighs only 7 lbs with accessories, vs 70lbs for the cast iron diesel block, so I would set the gearing up so that you don't have to pedal all that weight around much, by stretching out the gearing - if the motor will allow it on inclines, you should be able to get a longer powerband to the road which emulates how a gas bike would apply power, and save the drivetrain from the crushing torque.
KTM50 Schwinn Chopper - 6000W E-Motard - 52cc Auger BMX - 9sp+CVT 52cc Cagllari Moped