Motorcycle Repair: Kx250 will not idle, vacuum leak, best bet

Question
I just put a new piston in my kx250. Since i did that the bike will not idle i can get it started but soon as I let off the throttle it shuts down. Do i need to adjust my idle screw or what could i do to make it to idle.

Answer
sounds like you have a vacuum leak somewhere. Your best bet is while the bike is running, spray carb cleaner around the engine and where the carb boot connects to the engine. If the idle goes up, down or kills the engine, thats where youre leak is

Hope this helps!

~Mark