[recracer]

History first . after the muffler install (pz30 carb) tried 115 main jet stumbled badly , dropped to a 105 main and it ran great free revving , thought i mite be a little on the lean side . left it alone for then . two weeks ago started stumbling at high rpms again ,not as bad as the 115 jet tho . so i thought maybe i should raise the needle . well that was fine but no change in the stumble . OK needle won't fix a full throttle lean anyway . put in a 110 main jet . it loves it , still no change at high rpm . plug looks great full throttle chop check . so i tried another cdi ,performance one i had bought awhile back . feels good , but still no high rpm change . now the question . Faulty coil. ground , weak valve springs ? Valves adjusted as well after stumble started .