looking for some help w/ my WR426 02. I live in Moab UT and do the majority of my riding here. My bike recently is not performing at 1/4 to 1/2 throttle especially @ track conditions or when instant power is needed. After reading my manual and following instructions for jet needle adjustment, I have moved the clip to both richer and leaner positions. When clip was moved up from factory setting problem seemed worse especially exiting a corner bike was cutting and popping? When setting was moved down to richen, my bike ran like a raped ape power was consistant throught entire throttle range,(stoked) then 10 min later of hammering my bike instantly went to [@#$%&*!]. My bike started to sputter and pop major backfires, did not want to stay running, finally stalling. Got home pulled the plug soaked. What is going on here? Carb is off and apart looking for some help please? I am also about to install T handle fuel screw. Any sugestions or comments about this?