I have an '04 WR450 and I have a terrible stumble when riding in any gear from approx. 1/8 to 1/2 throttle. I started w/ the jetting since it was stock when I bought it but had a GYTR performance tip installed. It stumbled like this when I bought it. I installed the JD Jetting kit, blue needle 3rd position. I put in a 168 main jet, 48 pilot, 40 leak jet & #70 starter jet. Airbox unchanged and fuel screw is 1.75 turns out.....the stumble got more pronounced but still idles great and has tons of power w/ no noticable bog just like before. I live in Michigan...alt. is approx. 600 msl-2000 msl. Temp is avg. 65-80 deg f. After reading several other posts I decided to adjust my TPS. The Range says .58-.78 VDC output. I was at .55 so I adjusted to .77. I heard the idle increase as I did this. The stumble was still there...seems to be just as bad as before. I unplug the TPS and the thing rips....NO STUMBLE anywhere! It runs the way I think it should now, but I'm worried it may screw something up long term if I leave it unplugged. Am I asking for trouble here...like by burning up my exhaust valves or something 'cuz the CDI mapping is wrong at certain RPM's now? Anyone have any experience or input w/ this? Thanks for any help guys.