I have a 2004 TTR-125LE, I dissassembled and cleaned the carbuerator due to it not starting. The carbuerator was filthy and after reassembling it it I was able to start it, but I have to twist the throttle a little on start up even after it is warmed up. It idles just fine after starting. I have been playing with the mixture screw on the side and the adjustment screw on the bottom of the carb. Nothing seems to have any affect on the initial starting. Also my choke does not have any affect either. I pulled the choke out of the carb and it is moving when pulling the choke handle.
I will kill the engine after running fine for 10 minutes and still will not start unless I twist the throttle slightly.