Your flow of fuel is dictated by the engine, throttle position, load, carbs/jets, RPM etc. A Honda engineer figured all this out 30+ years ago. The bottle neck of the system are these variables. As long as the petcock or petcocks flow a small degree more than that worst case max flow scenario as dictated by the variables, you are cool. The bowels fill up and the float needles shut off the flow (all properly adjusted of course) and that is that. I replaced my stock petcock with 2 after market jobs on my CR 750 glass tank. They are 1/8 inch ID and the bike has V stacks and open un-baffled 4 into 4 meggas with 84 main jets. The petcocks keep up fine to 10K rpm.
