ican start my 250ex and as long as my thumb is on the throttle it half *** runs. ive had people say on the forum that its a main jet but today i rebuilt the carb and drained the tank.they also said that its angle sensor but i cant find it. oem parts doesnt carry it and nobody will help me with replies. it also has a stock muffler but has no packing in it. heres what happens i start it , runs then will try to idle then dies you get it started keep your thumb on the throttle and rock it it will die i havent been able to ride in 2 weeks its killing me please help.[img]i/expressions/face-icon-small-sad.gif[/img] will the muffler hurt it or what.

 

did this start after you removed the packing from your muffler? its probably running a little lean and you might need a bigger pilot jet. and your float could be off.

and put the packing back in a noisy bike doesn't make you go any faster.