I run hjr mx hardcore port, and man this thing rip! I have keeped the stock carb as i were seeking for the max low torque. My mod is, t5 exhaust, +4 timing, hjr noss head 21cc dome, wiseco .020, true weld crank, reed spacer, vforce 2, pod on carb, 26mm stock carb, shift star mod. I had to put 330 main, mid clip, and 30 pilot 1turn and a half on screw and now ride like a champ. I ride in tight sand trail and mx track, and let me say that when i hit the pipe out of a corner, nothing can stop that things! Just wanna share my experience