Oil in my Airbox?

[Guest]

I have oil leaking out of my airbox! I assume it's coming from the crankcase vent tube? Does anyone know what would cause this and how to fix it?

[daveo]

That's usually a symptom of rings going south, the compressed fuel mixture leaks past the comp. rings and pressurizes the bottom end, causing oil to back out up thru the breather

[Pillage]

That s#cks
It seems to have plenty of power, but it does blow some oily smoke out the exhaust (at least no one tailgates me :twisted: ). Any idea how long the engine will hold out before it becomes too weak to be fun? Do you think heavier oil would help to slow down the process?

[daveo]

You can probably ride it indefinitely, or until the plugs start oil-fouling too much.(which they may not do, as the oil control rings may still be sealing) It's mostly an annoyance with the oil blowing around, unless it's dripping in front of your back tire, that would be a safety issue...going to a 50 wt. oil may help a little, but probably not much. Gradually, it will start getting harder and harder to start when cold, due to lack of compression, then you will know it's time...