Q: Why does my Twin-Cam leak oil out of its air cleaner?

Answer:

In a Twin-Cam you may notice blow-by at the breather, which leaves traces of oil down the side of your bike, usually staining the heat shields of your exhaust and dripping down the oil bag. The reason for this is, even with the standard petroleum based oil, the scavenger side of the oil pump is marginal for the motor. The oil pump cannot sump the oil out from the bottom end quickly enough which causes it to load up in the top end and flow out the breather. Your local shop can correct this by installing a Fueling Twin-Cam oiling pump.