I have a 350 Bruin that runs great. It starts cold very quickly but it has to run about 5 minutes or it will die at idle (no choke) If I turn the idle speed up then when it warms up it idles way to fast. I have had this bike for 5 years and it just started doing this. I use to be able to choke it for about a minute then take off the choke and it ran great from then on. Any ideas?? Carb is clean valves are adjusted...

 

Take the carb apart and clean it. Could have something hanging up in the idle jet.

 

Thanks Sparky, but I took the carb down and cleaned it really good, No change. I just found my primary side of my ignition coil is out spec by about double. This might
address one of my problems with a miss at idle, Not sure about the idle speed problem though. Any more help would be appreciated...

 

Try air/fuel mixture screw. Should be about 1.5-2 turns out. Your probably on the rich side.