iv just bought a gillera runner 125 2stroke and the spark plug keeps getting oily and makes te bike cut out and not start but if i clean te plug and put it back in its ok for a wile then does the same wot cud it be ???????????

george, March 2010

Yeh, thanks for that Adam, nice one! Of course it could be other things as you previously pointed out but there's no harm in changing or re-newing a plug, i've had brand new one's totally US! PS, you work on these things all week and then answer Q's on here as well??!! :)

2 stroke Ted, March 2010

The plug it supposed to take is an ngk BR9ES.the higher the number the cooler the plug runs contrary to popular belief.hi ted :)

adam bike doctor, March 2010

Hi, first things first, check the spark plug to see that you have exactly the right grade for your machine, the make & grade number are on the white ceramic part. You may have a cooler running plug that is unable to burn off the oily deposits that normally would be with a hotter plug. Sorry, i can't help with what plug you should have.

2 stroke Ted, March 2010

well the 2 stroke one has a certain amount of 2 stroke oil pumped into it vai the oil pump ,i would say the carb is flooding a bit and washing the combustion chamber and piston crown and fouling the plug with the black oily fuel.you need to check your float and float needle and make sure they are both clean and set right ,there is a certain float height that they have and if its not set right or there is some debris in there stoppoing it from seating up properly and shutting of the fuel flow then this will cause this problem.

adam bike doctor, March 2010

Is it a 2 or 4 stroke?
Either way too much oil getting in the plug which suggests the rings to me. Maybe need a rebore as well. What are miles and year etc. Has it any trick bits?

bb, March 2010