40 mph seems to be the practical limit. Mild tuning will get you there quite easily with a 67cc. Always pushing the engine limit, not gear ratio (with the kit)The makers of the engine claim that the motor can do 35 mph, but can it really go that fast or even faster? How fast have you gotten your bike to and what did you do to make it go that fast?
That's what happened to me and I did take the life out of that motor! haha! Lucky for me, Dean helped me replace and fit some quality japanese and italian bearing. After that my HT motor ran like a champ and I could go WOT without the motor sounding like it was struggling.This is about the fastest that I've gone with the same setup as well. Engine was turning 7400rpm! I feel bad now that I did it. Probably took some life out of the thing.