What makes oil drip out the air cleaner on a 2003 harley davidson sportster?
Nothing is damaged or needs to be replaced. The above is correct that the problem is blow by. But that’s all that’s correct about that answer. When a cylinder fires, there is a small amount of burnt gasses that “blow by” the rings on a piston into the crankcase. In older cars, this was vented to the atmosphere. In newer cars and bikes, because of EPA requirements, this blow by gas must be vented back into the intake system. This “blow by” gas carries with it a small amount of oil. Harleys are notorious for weeping oil out of the air cleaner beacuse of the “blow by” recirculation. Not a whole lot you can do about it (and stay EPA legal) except to be aware of it and clean the oil from the outside of your aircleaner occasionally.
