I thought maybe some of you 1stgen yfz guys could help being it is essentially the same motor. i bought the bike used and it had a full dsp pipe. i dont know if the carb was jetted or not but it ran fine up until 3 months ago. i bought a FMF titanium silencer since i blew the dsp apart. i didnt get a pipe clamp with the new muffler it fell off and i havent rode since. now that i got some money i started fixing the exhause and i had a brake problem got that all done. and i noticed the carb leaking from the top of the accelerator pump but the motor was running fine. after i took everything apart i noticed the diaphriam was cracked. i ordered that but havent gotten it in yet. i put everything back together and the carb didnt leak anymore even with a rip in the diaphriam, but now it backfires and wont idle. all i took off the carb was the bowl and the bottom of the accelerator pump?!?!?!?! what the hell is wrong

 

I'm betting the pilot jet is plugged, or you have an air leak.

DV