Wondering why my 89 evo is losing oil out of the crankcase breather filter after a couple min. of riding at 55 or over.all oil lines are connected right... the oil tank is not over filled,and my breather gear is timed right... no other time does this happen... I'm a fairly seasoned harley wrench but as always... your never too old to learn... thanx to all who respond...
Dirty kurt in Hawaii
[email protected]

Bad piston rings?

Pressure in the crankcase. Possible bad piston or broken piston ring.

Excess pressure, possibly due to carbon build-up on the piston, head, and valves. It may be time to pull and rebuild the engine. You may be able to get by with simply installing new rings and removing any carbon. Oil may be getting past the rings and being burned (forming carbon). What is not burned may be blown out the oil vent at high rpm. It's very similar to what happens on mowers, particularly those made by B&S.