The bike has very good free RPM's now, but the only thing I've noticed is that it really doesn't have anymore lower end torque? So, acording to the directions for a smaller 48cc you don't want to shorten the pipe any for that?........Just leave well enough alone?
See, it will run up into the mid 30's now.............but I try to keep it around 20's. I'm just trying to figure out how I can tune it for a little better torque. (They say not to for smaller motors?) Uno, 1/4" either way.