Motorcycle Repair: Kawasaki EX 250, mity vac, air evac

Question
I have a 1995 Kawasaki EX 250. I noticed when the engine temperature gauge needle reached midpoint center, the bike keeps on dying at low RPM's and would only run when the throttle is open. I tried running the engine for another 5-8 minutes with the throttle open and the engine just died afterwards and saw my header pipes glowing bright red/pink. After that the engine would not start until the engine cools down. Most of the time I would wait till the next day and it would start and idle/run fine for about 10 minutes and it will go to the same cycle again. I took the carbs out thinking it's probably flooded but to my surprise it wasn't. I did almost everything. Spark plugs are new NGK's. Gas in the tank is new and fresh. I'm actually even using 92 octane premium gasoline. Valve clearance/gap are within specs. Intake is .004 and .006 for the exhaust. Carbs are synch as well. I'm really lost and don't know what to do next. Thank you very much in advance.

Joey

Answer
Hi Joey,

I suspect the choke is "On" or not working properly and causing an excessively rich air-fuel miture long after the engine reaches operating temperatures.

Aother area to check is the cooling system proper operation.

Coolant needs to be 50/50 ratio. The system is an air free system. Anytime the system is opened to air other than removing the radiator or reservoir caps, air enters the system and must be purged. A special tool is needed to do this mandatory task. Check into Mity Vac's "Air-Evac" tool.

Respectfully,
Mark Shively