Unless you have an engine dyno, making guesstimates about jet sizes is a colossal waste of time. The best process for people without access to dyno facilities is a long hill where the engine can be run for several minutes at wide open throttle, and a stopwatch. Make one change at a time, make a test run, and record the time for a particular run. Then make ONE change, such as jetting, ignition timing, alteration of the centrifugal advance curve in the disttibutor, etc. "Rinse and repeat"! Advice gotten from an interrnet chat room (including mine) is worth exactly what it costs you to read it, no matter how much the guys with double-jointed elbows pat themselves on the back!
Jerry
