it has reached its maximum rpm for the set up you have and has likely started to go into 4 stroke it wont ever do 100 mph however much you spend on it just be happy enjoying your freedom without having to pedal
it has reached its maximum rpm for the set up you have and has likely started to go into 4 stroke it wont ever do 100 mph however much you spend on it just be happy enjoying your freedom without having to pedal
I also had this happen where it started detonating at top speed.
Higher octane fuel and/or timing retard helped, but really the answer was a better timing curve.
See Jag's CDI.