If your crankcase breather is passing oil, chances are that something's wrong (Okay, we know something's wrong, but don't be too alarmed). Here are some things to look for while you're searching for the source of the issue:
- Too much oil in the crankcase (overfilled!)
- Engine speed is too high
- Oil filler cap or oil fill gasket is damaged or missing
- Breather mechanism is dirty, damaged or defective
- Piston ring gaps are aligned
- Piston rings are worn
- Blown head and pressure is being blown out of the breather
