Way to much oil coming out air cleaner - 2003 Harley Davidson XLH Sportster 883 Hugger

Oil coming out of the breather is natural and normal, with basically no way to stop it. There is about 1/2 qt of oil in the bottom end of an engine, as the pistons travel downwards, the air that is under them is being pressurized and is vented out of the engine by a rotary breather valve in the case. The air picks up a small amount of oil from the bottom end as it leaves, then the air/oil mist is vented either into the air cleaner (EPA Regulations) or best if vented to the atmosphere. NOTE: WORN RINGS ALLOWINGS EXCESSIVE COMBUSTION PRESSURE BLOW-BY WILL MAKE THIS SITUATION EVEN WORSE. When it\'s vented into the air cleaner, some if it recirculates into the engine and out the exhaust, the rest saturates the air filter and then eventually gets blown all over the side of the bike. The best way to vent it, is to route a hose from the breather system down to the frame between the engine and trans, run it under the bike on the right side, point the hose down to the GROUND and zip tie it in place.



To stop the leaking breather BOLTS...remove them, and use brake cleaner to completely remove all oil from them, the washers, brackets and threads in the head. Use liquid teflon thread sealant on the bolt threads, and a light film of black rtv on the faces of all the washers and brackets, install everything, let sit for 24 hours, then ride.......if done properly and rtv is CURED, it won\'t leak.

Also note that most HD\'s with the oil tank mounted under the seat and are left sitting for a couple months will PUKE oil from the breather, this is due to the gravity....the oil will slowly seep through the oil pump and collect in the bottom of the crankcase and get blown out the breather when the bike is started.



Also:

The HD engine design is a dry sump engine, but there is always a small amount of oil in the bottom end....THIS IS WHERE THE OIL MIST COMES FROM......it is "possible" for too much oil to give your symptoms, if you have too much oil in it, the oil tank is vented back into the cam compartment, causing excessive oil build up in the bottom end, if this were the case, the oil would be PUKING from the breather, because the oil pump does not have the ability to scavenge that much oil back to the tank that quickly, which in this event, the tank doesn\'t have the room to store any way.

But even so, this is an all too common question and the symptoms are seen on almost every HD on the road.....could it be possible that EVERY HD has too much oil??? In my answer, I tried to explain WHY this happens.....even with or without too much oil.....this will still happen.