2001 YZ250F Altitude is 5500' JD jet kit currently set exactly to specs listed in book: - 175 Main - Red Needle Position #3 With the choke on, the bike idles awesome and the throttle is very snappy. As soon as you turn the choke off, the engine dies immediately. Trying to keep it running with the throttle 1/2 open makes the motor cough and sputter, and its very hard to keep it running. I have cleaned out the carb 5 times and it makes zero difference. Aside from the main jet, and need, all other pieces are stock. Is there a circuit that is bypassed by the choke? Please please help. Im on the verge of tears over this.