[tvnacman]

Originally Posted by rks

Has to be the crankcase ventilation tube....it is plugged, or kinked in some way, and as a result, not allowing the normal pressure created in your engine to vent. If not corrected, you will blow an oil seal, most likely one of the crankshaft seals.

The vent tube runs from the valve cover to the air box, as bandito2 stated. Check it out soon, or you will have much bigger problems.

I 2nd this!

check your air filter.

John