02 400ex help

[KX250frider]

I bought this 400 not running, re-timed it and rebuilt the carb. It now will start but will not stay running unless you keep it at half throtle. Any thoughts on this? Battery is shot could this be causing the problem. I have just been starting it by putting a charger on it, but it kicks off as soon as the engine fires. Any suggestions?

[Stark]

What size pilot jet are you running? What is the needle clip position?

Sounds like a carb jetting situation to me.

http://www.exriders.com/vbb/showthread.php?s=&threadid=394028&perpage=10&pagenumber=1

[fearlessfred]

i would replace the batt. first before making any other changes

[wilkin250r]

I've seen bad batteries cause problems, it's weird.

Try this. Disconnect the battery completely, and jump start it with a car. They're both 12V systems, so it will work just fine (but the car shouldn't be running, or you risk blowing the voltage regulator). THEN see how it behaves, and let us know.