I bought a SSR Lazer 5 for my son. Mainly because of the honda clone motor. They're versatile and interchangeable. It has a 72cc upgrade and 22mm carb. It mostly runs in the upper rpm and will do 50 easily. The problem is the gears 1st is too low and 2nd is too high and cannot be shifted. It's scary with cars because it doesn't start fast enough. With that being said we are in the process of swapping in a 125cc semiautomatic 4 speed. I'll tear apart the original engine and see if I can get gears to shift.
