I've got a '00 WR400F with an FMF power bulge header, Power Core 4 combo, twin air filter, airbox lid off. That's all for the engine. I can't get this bad boy jetted right. I've gone up from 168 main jet, to 172, and now 175. When you crack the throttle wide open it'll bog out. The 172 would hesitate when the throttle was cranked, then rev. But I knew it wasn't jetted spot on. The 168 and the 175 would bog until you let off and rolled it on smooth. The temperature has been nearly the same for each ride on each jet. Do I need to richen the pilot and jet needle circuits? I was hoping that a richer mj would solve the problems, but no such luck. If anyone has this setup or something similar I'm all ears (or eyes). Thanks for the help.