I posted another topic when I had the weak/no spark question which is fixed and I thought would've helped performance but it hasn't Just took it for a ride and it starts right up and runs good but for some reason top speed used to be close to 50mph now is only 28? Can't feel any slippage in the clutch/belt but the engine just doesn't rev like it should. Hit's a certain RPM and just stops climbing. Took the carb apart and cleaned it up including the main jet. Anyone have any ideas on what could be the problem?