Front Freewheel Cranksets, adapters, and various chainwheel sizes, sold here, separately (e-bike store)
http://www.cyclone-usa.com/store.php?crn=203
SICK bike parts also has Front Freewheel cranksets for SQuare Taper Bottom Brackets. (SICK is awesome! )
http://www.sickbikeparts.com/Products/Cranks.html
I'm mostly interested because of these two ideas:
A person in a state with certain clauses in the motor bicycle laws is not required to use pedals, if the bike is under certain CC and is actually a bicycle frame and wheels. I am trying to remember what state now, will look in the forums, or someone can chime in. This would allow a RH drive side and use of common wheel parts, with a freecoasting hub.
A person who wants to pedal full time anyway can use it like this:
Yes, it would be true in this application. If the engine is small like 32cc, and the automatic clutch is still used, it shouldn't be a problem, because pedaling full time would work well on some applications, especially since you say it can be pedaled with the engine off, correct? 2 cycle engines used for this will have a fast throttle response, so letting off the gas lever would disengage the clutch nearly instantly. A dual kill switch setup with thumb buttons for each hand would be effective for a safety measure. Extra care would have to be taken to let off the gas when changing speeds.
Someone on this forum once modified a Shimano hub or a shimano freewheel to use a standard BMX freewheel in place of a lockring or smallest cog. This would eliminate the multi speed ability though, but would allow use of spacers to create a place for the motor chain to fall into if it ever derailed due to the motor quick release bracket loosening.
I would use this on a bike with BMX pegs so I could start the bike, then ride on the pegs like a sport bike. With a short crank like 160-175, you shouldn't have to worry about grounding out the pedals.
The front freewheel cranks sold for shift kits could also be employed. This would leave one with ONE motor speed gear, and various pedal speed gears (minus deleted gear for space to prevent chain rub). This would be IDEAL for me because I live in TX where the multi speed motor/shift kit is not legal, as far as I know. It would also be a perfectly fine setup for anyone. With pedal speeds, you can always crank your feet on the hills to power up, then coast for the downhill and flats.