kx 250 plug keeps oiling up?

i have the same problem with my kx250 , its a 2001 model , the bike will run sweet for abit but the cuts out and i take the spark plug out and its oiled up so when i clean it and put it back in the bike goes well again for abit but then does the same thing,

Glen
February 2011

what mixture are you running it at?i always use 25ml of oil to every litre of petrol and make sure i give it a good shake before i put it in and also a good shake in the tank before i ride it.always turn the fuel off too when you are not using it as the oil will settle to the bottom of the tank as its heavier then the petrol.other than that the plug can get oiled up due to a right hand crank seal leaking and allowing the oil in the crankcase to be sucked in down the side of the crankshaft!another reason is the bike running too rich (looks like oil) when it gets too much fuel its will go black because of the carbon in the combustion chamber and the plug will get fouled all the time and short out accross the insulator nose.check the fuel doesnt drip when the bike is being used from the overflaow pipes on the side or the one at the bottom of the carb,also check the float height or fuel height in the float bowl of the carb and the position of the circlip on the needle in the throttle slide in the carb (should be in the middle groove as a rule)well good luck hope all that helps you ,adam p.s let me know how it goes

adam bike doctor(by profession)
March 2006