Oil leaks from breather box

I have read both your questions and after taking both into consideration it sounds like it needs new piston rings. On a gas engine it is called blow by but both have a piston with rings on them, as they wear the end gap gets bigger and bigger allowing compressed air to bypass the rings into the crankcase where the oil is, the breather is there to allow air from the room to enter and exit as the piston goes up and down to avoid pressure or vacuum in the crankcase, the air on the top side of the piston is supposed to go into the tank but in your case some of it is going around the piston rings and into the crankcase building pressure and blowing oil out. There is not much inside a compressor like a gas engine, taking the head off and the oil pan should let you take off the connecting rod bolts and push the pistons out the top. This answer is based on the two comments of cant build all the air pressor and it is blowing oil out the crankcase breather. If you hit the 80 psi and unplug the compressor can you hear air coming from the limit switch box that the power cord goes into ? I will wait for your answer to continue.

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.

The problem is the the air breathers inside the rocker covers. Sad to say,but nearly all of them do this. One solution is to take off the air filter cover. There should be two bolts..(one on each side of the inside of the housing) that SHOULD have hoses hooked to them. If they do not have the hoses hooked to them,then that is your problem. See,these bolts are hollow,and have a nipple on the ends of them. These allow the top end to "breathe",a crankcase pressure relief if you will.Anyway,..these nipples are SUPPOSED to have a small hose on each of them,that re-direct the oil/crankcase pressure, into the carb/throttle body,which eliminates the oil running into your air filter housing.Check to make sure they are in fact there,and let me know what you find.

I just got done repairing the very same engine with the same syptoms that you mentioned. I had considerable oil coming out of the fuel pump breather hole (copper colored mesh). The source of the problem: a blown head gasket. This will cause the piston, in the compression cycle, to pressurize the crankcase through the head gasket leak into the valve lifter chamber and push oil out the vacuum tube (bottom hose) leading to the fuel filter . To fix, you will need to first disassemble the cylinder head from the engine. To do that you first need to disconnect the three hoses to the fuel pump. Remove the cover to the air filter, remove the air filter and the screw in the bottom of the filter housing. Remove the four bolts attaching the plastic flywheel cover and remove the cover., remove the cylinder head (8 bolts)and check the head gasket to confirm it is blown (you will probably see some dark brown or black discoloration of the head gasket between the cylinder and valve lifter chamber. Carefully remove all old head gasket material from the block and head surfaces and clean the head bolts. If either your cylinder head or block surface looks ugly, you may need to get them resurfaced (flatness tolerance is very small ) Buy a valve gasket set (contains the head gasket and other needed parts)
Remove the valve rocker arm cover (4 bolts) from the head. Mark the exhaust and intake lifter rods (they are different) Clean the combustion chamber. If your engine has many hours on it, you will want to remove the valves and check the valve rims and seats for wear or pitting. You may want to hand lap the valves to insure they are seating perfectly.
I coated my head bolts with an anti-sieze valve lube compound. The B&S service manual calls for this. Reassemble head and torque head bolts to 220 in.-lbs. (4 stages) Do very accurately. Compress valve springs, install push rods and set clearances between rocker arm and end of valve stem. Turn flywheel to move piston so that both valves are closed before setting clearances. install a new fuel pump on the plastic flywheel housing. I removed the breather from the top of the engine (two small screws) and checked the reed and oil drain hole, and resealed the breather cover (you will need to pull the flywheel to get to one of the breather screws. I used a gray high-temp rtv liquid gasket compound to reseal the rocker arm cover and breather body. Reassemble all parts and screws and use small torques as listed in Briggs Service manual. I put in a new spark plug, changed the oil and filter, and breather tube, and o-ring at the bottom of my oil filler tube. That should do it

There should be an oil breather tube on the left side of the engine leading the airbox. Make sure it's there and cleared out. If the previous owner removed the air box and put on pod air filters, he may have plugged the breather line.

Also, check your oil level. Use the sight glass - only when the engine is off and the bike is level on the center stand. The sight glass is on the clutch cover - right side, bottom of the engine. There is a mark on the glass showing the correct level.

Oil coming out of the breather is normal on these engines by the way of design, 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. 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...Be sure to point the end of the hose down & away from the tire.
If your breather bolts start to leak oil...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 ...

Good luck...i hope this helps

Check your oil level first, you may have too much oil in it. The grey sludge is nothing to worry about, and is usually caused by condensation forming inside the engine as it cools down, caused by short distance riding, water mixes with the oil, causing this grey thick sludge. I would suggest changing your oil and filter, but mabey before hand, flushing out the engine oil with some cheaper oil, or engine flush. Sometimes the oil going into the air filter, is a sign of to much crank case pressure, caused by worn or gummed up piston rings. Try some new oil, 10W30, and a new filter.

Rick, since 1994, Harley has used what we call a "head breather" system in that the crankcase breathers are located in the heads. This was done in an effort to reduce the amount of oil that gets into the air filter. In earlier case breather model engines, the oil would pour into the air filter if the bike had been sitting for a few months. Prior to that, the bike would "puke" what looked like a quart of oil on the ground below the bike when first started after a long period of sitting.

If you'll remove the air filter cover and element, you'll see that the large bolts that hold the breather onto the heads are hollow. Inside the rocker boxes, there are small rubber "umbrellas" that are opened and closed by crankcase pressure. These are designed to allow your engine to breathe without an excess of oil being blown out. Still even though this system is better, a little oil still gets into the air filter. You can either keep this cleaned out or you can replace the "head breather" systems with an aftermarket system that changes the location the system exhaust crankcase pressure from. Also, you can change the "umbrella" seal and put in new ones. It isn't that difficult to do on the front head. The rear head can be tricky since there isn't much room to get to the bolts to take the rocker box cover off. The umbrella seals are located in the center section of the rocker box cover.

Good Luck
Steve

You need to service the crankcase breather system. Basically, this means taking apart and cleaning all the goo out of the area where the crankcase breather tube goes into the air box. Also check the air filter for oil saturation and replace if needed - and clean any accumulated oil from the inside of the air filter box.

It is an air intake silencer. It quiets down the motor when you are throttling up.