I have a Zuma I built up a few years ago. I just removed the heavy ported piston and cylinder to put on a fresh 70cc piston and cylinder.  The ported one gets about 8 miles to the tank but will hit 62 mph with the same var weights in the transmission.  It has the 18MM big bore carb., carbon reeds with aftermarket reed cage, big tuned pipe, kevlar belt in the trans. Heavy clutch and springs.  Aftermarket varaiator with my own made weights.  Aftermarket tires, light kit, rear signal delete, signals are in the side reflectors. Something I did and others started copying me on the net. Also has duel on headlights, both high and both low. You can have the 50cc piston/ cylinder and the heavy ported piston/cylinder and all the stock stuff I have and new in the box aftermarket stuff I have.This is a great machine, never lets me down.  Starts right up. I only use it to take it camping to scoot around as I have a 650 SUMO my main ride.  Come see it  you wont be disappointed.   Msg me if you have any questions. Will not ship unless you contact me with your shipping company pick up.