I have a 95 CBR 600F3, what does it mean when I find oil on one of my spark plugs. Is this a sign that I need to replace my rings or what. It does not smoke but it does back fire when you let out of the throttle. Of course that cylinder is not hitting like the other three but it runs OK. What does that mean exactly? Any help would be greatly appreciated.

 

Finding oil around your spark plug could mean your valve cover gasket is leaking around the spark plug well and leaking down to the plug. The backfiring (actually afterfiring believe it or not) is cause by a lean condition when you close the throttle. This could be caused by an exhaust leak or the main jets could be too small or many other causes.

 

Could be worn valve guides, this may explain the backfiring as petrol will always have access to the chamber.

 

If the oil is just around the plug gasket I wouldn't worry. I found some of that on mine and I was told no worry. if the oil is on the electrode or the bottom of the plug, you have some problems and will need engine work.