i just think those things look like they got taken off a supermarket checkout or something, which is fine if they build the wal-mart theme bike, but any other chopper should have a nice chain drive, if you're worried the primary can't take it use a double chain. choppers need parts that can throw grease around.
as an addition some neat bikes.
http://www.dolmette.com/
24 chainsaw engines combined onto one harley tranny. with belt drives. oh well. but still neat.
under the picture and souind there's videos of the thing actually running.
http://www.werner-br.../kultliter.html
1440 cc bike. engine is one cylinder taken from an aircooled tractor engine. the 4 valve head is machined from a solid block of aluminum. the fork is wood. the tank is part of the handlbars. the tires are front wheels of a tractor. drum brakes, kawasaki oil pump, shovel with hand forged leafspring as a seat, volvo carb, harley tranny. quite a piece of work. and it only has a kickstart, no pansy assed electric start.