If you mean 14/12 carb, then a 65 jet sounds really big for a stock setup. Being that rich hurts performance. Look into an expansion chamber exhaust and high flow airfilter and jet accordingly to those two things. Upjetting doesn't help a stock bike, especially since most came a little rich out of the factory (can't speak for all though.) It only adds more fuel into the mix when something is changed such as a higher flowing air filter. More air in the motor will need more fuel to burn with it, see?