I have to get one... Im obsessed with the magnums. Not cheap though... You said "people are doing away with the ped option". Does that mean you can get rid of the pedals, and just bump start? I gotta say, thats what I would do...
Ever seen one of these? Yamaha FS1:

It was known as a FIZZER, or FIZZY (FS1-E)
That one is from 1974 ('M' on plate is year designation)
Pedals locked into forward position and move opposit way to swingarm (as they are ahead of pivot point)
Couple of friends had them, with porting and expansion chamber they would do about 60mph.
Its a disc valve motor, you cut disc to increase intake timing (throttle and 'choke' cables go into rightt engine cover)
PJ