I recently have finished my 1st build, a thatsdax 66 cc kit on a Schwinn Delmar. It runs great but I want to get a little more power out of it. Any suggestions? I also have been wondering if anyone has run across a bigger engine? Edit: I have found some parts that are what I'm looking for. Maybe you guys are interested too. http://www.zoombicycles.com/eShop/6...over-80cc-Slant-Head-Cylinder-Cover-A-2B.html Above is a cylinder head cover for $13. One review said that it increased his top speed by 7 mph. Sounds like a cheap upgrade. http://www.zoombicycles.com/eShop/6...i-racingcarb-Addon-Racing-Carburetor-5-2.html Here is a racing style carburetor that is a bit pricey but sounds like it gives you a major boost in power.