Oil in air filter

[MuncyBob]

I'm noticing a small amount of oil on the underside of the air filter and a bit around the rim of the carb. It's been this way for awhile but seems the amount showing up is increasing a bit. What's going on?

 

[frischtr]

Valve lash probably needs adjustment.

 

[ovrszd]

Hmmm,, just guessing that the engine has a Positive Crankcase Ventilation (PCV) valve and system??? If so, it's plumbing into the airbox which creates a vacummn in the engine drawing off any blowby gases. That creates an oily condition in the airbox and/or carb if the engine has significant blowby. Blowby is usually caused by combustion pressure seeping past the piston rings and into the crankcase. No big deal unless it's so bad that it plugs the air filter. I've saw engines with puddles of oil in the bottom of the airbox and still operate fine.