2002 Suzuki RM250 - Dies after warm up, restarts after cleaning wet plug

Question

Has a fresh top end. Carburetor cleaned. Fresh fuel mix. Reed valve looks ok. Air filter and intake, ok. Has good spark. After it dies, the plug is wet.

Restarts after cleaning plug?

I checked the stop switch and harness. I inspected wiring and connectors, ignition coil primary and secondary circuits. Checked for intake air leaks. Runs great than just dies and fuel fouls the plug.

Could a malfunctioning or maladjusted power valve be causing this?

How do I check and adjust them?

Also, could it be the carburetor power jet solenoid?

How do I test it?

Answer 1

Here's a theory

Too much fuel built up in the crankcase.

Could be from a petcock leaking and a stuck float.

Here's the theory

Too much fuel in the crankcase.

You start the bike.

It begins to heat up while your blipping the throttle

Engine cases begin to get hot.

Fuel thins up with the heat.

You start riding and crank spins up and begins to throw the excess fuel around in the crankcase.

Mixture get's too rich and your bike dies.

You pull the plug and see that it's wet.

Solutions and things to check

• Petcock - is it leaking?

• Needle and Seat - is the float sticking open and allowing fuel to drip into the crankcase?

• Drain the crankcase - Was there a bunch of fuel in there?

Hope it's as simple as a stuck float. Good luck.

Answer 2

It sounds like the issue here is with air-fuel metering. A wet plug means unburnt fuel, so you either have too much fuel or not enough air making its way into the cylinder.