Greg:
I had this gas kit on a beach bike.
http://www.gasbike.net/grubee_skyhawk_gt5_66cc_80cc_slant_head_standard_finish_bike_motor_kit.html
Pros: Cheap, 2-stroke had great torque, $1.82 per fill up avg 150 miles per tank, 30 mph +
Cons: Multiple chain breaks-never could get proper alignment...