I know the filter won't cap it but may become clogged and will result in capping it. problem fixed no more oil loss. Some days it doesn't do it. Your breath will come out the oil filler cap hole in the valve cover. well, if you added to much oil, the motor would naturally get rid of it. How much pressure should thee be in the crankcase? When my engine is running (supposedly rebuilt but just fired for the first time) there is a big whoosh when I remove the oil cap and the idle changes. The crankcase breather system is broken up into two parts on the M62 8-cylinder engine. When the engine is revved that hign there is a lot of crankcase pressure caused by ring blow by etc. example if the air is coming out the exhaust pipe - this might be valves not closing or a cylinder - cylinder HG fault. I thought maybe the piston rings could be bad creating too much crankcase pressure. Got it running and then I started having an issue with a steady stream of smoke coming out of my crankcase breather tube after the engine warms up. Coming out of my valve cover is some sort of breather valve, it is not a PCV. The system works much like the positive-crankcase-ventilation or PCV system on your car. As the RPM's rise the smoke increases, until its pooring out and out the exhaust. This kit is designed specifically to work with our belt drive kit. When the crankcase breather system becomes clogged, the air flow generated within the engine crankcase is restricted and doesn't allow the system to breath properly. I do not know the full load crankcase pressure, but they do drip about 2 oz of oil out of the crankcase breather every 100 hrs if run at 2400 rpm. I got a 2013 D13 and it has oil coming out from the blow by pipe, there's no code and everything is running normal. that the cone is wet with oil and dripping down onto the exhaust. The air with the oil mist is coming out through. Do NOT drill a hole in the crankcase!. help Polished Billet Aluminum; Includes 3/8 90 Degree Inlet; Excess Crankcase Vapors heart Vintage Gold Moroso 14 Air Cleaner $ 150. A PCV valve mounted in the valve cover is not going to suck liquid oil out of the crankcase (or valve train area) and in to the intake to be burned in the combustion chamber. I recently deleted my PCV system due to what I believed and what others on this forum believed to be excessivre oil in my intake. The bike is running well with no junk coming out the exhaust followed the tube from the bottom and it’s a oil breather tube off the back of the engine. oil coming out crankcase breather on 6211 Started at Sun Jun 17 22:05:08 2012 hi , when the 6211 goes down a hill oil starts coming the crankcase breather pipe. It includes everything you need to let your crankcase breath properly, while limiting the oily mess usually associated with other breathers. I got on the creeper today and investigated further where the oil leak was coming from. Got a 1098S a few weeks back with approx 12k Km (7k5 Miles) its in good nick but noticed oil dripping from the breather pipe bellow belly pan I also noticed that the oil level in the sight glass is way above the required level,,,, like out of sight I'm a "google mechanic" and know my limits. Each time a piston descends it will. Your breath will come out the oil filler cap hole in the valve cover. It smells like oil when it gets hot. Recently I noticed oil under my ranger it came from the crankcase vent line. A lot of oil is coming out of the breather cap, i purchased a new one and still having same problem. The system is not "doing its job" if it is blowing roughly half the crankcase oil out the breather every 1,000 miles. The fitting coming out of the crankcase has one side going to the intake tube and one side going to the PCV valve. Re: Oil coming out my crankcase breather tube - New Holland TC29D Ok so that rules out worn rings. i have a 96 f150 with 302. Help Hey guys, just been at a race day and it was super muddy, i was in a race about 2 laps into it. The only other thing that I can come up with is that there might be something plugged or wrong with the baffles in the valve cover that separate the oil from the air coming out of the breather tube. Any way hears some pics of the cylinders. One of you guys mentioned to "check the crankcase breather hose to make sure it's not plugged". If fuel has leaked into the crankcase via an overflowing carb or vacuum valve fuel tap it would have seriously thinned out the oil. If the cap gets blown off, there is too much pressure in the crankcase. 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. The crankcase and trans breather has been relocated to the frame by the gas tank and uses a K&N filter. You should not be getting oil coming out of the breather cap. '78 R100/7 - other airheads I saw another thread that the poster had mentioned that he was experiencing oil coming out of the airbox, due to the crankcase vent. The car, during its normal function, creates a variety of gasses which can escape the piston rings. This aroused my curiosity to ask the rest of you this quesiton:. "Speedy Jim" suggested the following test - Clean everything up real well to spot the source. The crankcase and trans breather has been relocated to the frame by the gas tank and uses a K&N filter. To confirm the exact source of the leak,. The position of this tube gave oil an easy route to escape due to the built up pressure, pushing the oil out of the crankcase through the breather and onto the ground. 004 for both the intake and exhaust. I don't think the cases ever changed, just the amount of oil you put in them (less on later models), hence the dip stick marking change. If those readings are higher, it's rings. There is no way for fuel to get from the intake manifold into the rocker/valve area except via the crankcase. Any way hears some pics of the cylinders. I have a 86' k10 blazer with a 350 small block and my problem is smoke coming out of the crankcase vent/ PCV vale breather. I would suggest an oil change to a good diesel engine oil like Shell Rotella and then some hard work. I have a Trask on my bike and it is dry as a bone. This test just checks the breather box. The system works much like the positive-crankcase-ventilation or PCV system on your car. A certain amount of cylinder pressure will always find its way into the oil pan. Since my compression isn't that bad is the one that 135 the reason I have so much oil coming out???. Could potentially suck most of oil out of crankcase. Got a 1098S a few weeks back with approx 12k Km (7k5 Miles) its in good nick but noticed oil dripping from the breather pipe bellow belly pan I also noticed that the oil level in the sight glass is way above the required level,,,, like out of sight I'm a "google mechanic" and know my limits. Drag cars that are always at WOT actually just use a header evac system to draw out the fumes instead of a vacuum port precisely for the reason John mentioned. Oil spits out of the breather whenever I hold the rpm at 3,000+. In the first 10 minutes of the Kodiak sitting and running it looked like the Kodiak dripped about 1/8 of an ounce underneath the bile. +obviouslly the introduction of steam to the air inlet plays havoc with the A/F mixture. but what could cause that oil to come out like that?. Once you switch to an open filter, you are left with a hose coming from the vavle cover's vent that has nowhere to go. If there's not a great reason or need for the breather, I might do away with it myself (PCV actively pulls acidic vapors out of the crankcase, whereas a breather just lets the stuff ooze out when pressure builds). I've discovered some steam coming from the left bank rocker cover. could this bee from me filling the oil to much. Any ideas I was told it was bored. I had a similar problem with my 300C - found the line from the PCV to the intake was kinked, causing oil to blow out the other side of the engine through the breather tube. Of course it did not blow oil while they had it. If the mower is tipped the wrong direction, it can cause oil to leak into the muffler. If oil is blown out the breather the first day but none after the first day, then it probably is seeping. Seriously - get an oil catch can for the pcv side and a breather on the crankcase vent is fine. we're doing some trouble shooting on a car that is smoking from the crankcase vent and also the oil cap while the car is running/idle. This leads to the suggestion that the rubber hose ought to not be pointing towards anything which the rider does not wish to have covered in oil mist. My main concern is this smelly white smoke coming from my crankcase breather filter. help Polished Billet Aluminum; Includes 3/8 90 Degree Inlet; Excess Crankcase Vapors heart Vintage Gold Moroso 14 Air Cleaner $ 150. if i go above 70mph when i stop at the next red light there is oil everywhere that has been dumping out of my crankcase breather. Of course, if your air compressor is factory lubed for life (also known as oil less or oil free) you will not have an oil sump, and have no need of an oil fill tube. The crankcase has a limited amount of oil it can handle. Also all i have done to the bike is put a new npipe on and idle screw on it. No more leaks from where the gasket is, but I'm blowing a lot of oil out of the grommets, they fit fine but there's still oil all over the outside of the valve covers wherever there is a grommet. I need some help figuring out why all of a sudden i am getting so much oil blowby. That not only makes a mess of the paper filter but may actually make it fall apart. One of the ways to check if blow-by is too great is to put your oil filler cap upside down on the filler hole. so I have routed the breather out a hose and ran it out the back along the frame. The hose from the air filter to the motor is to let filtered air in. If, the crankcase is not overfilled as 30yearTech mentions then take the breather cover off (I've never run one without it) and run the motor. There was kind of alot it was all over the chain and airbox. Now, the breather situation. Excessive oil through crankcase breather Long story short I had the engine rebuilt for my 914-6 track car two winters ago and have participated in 2. I'm thinking that the breather tube needs to be much taller and more vertical and this will help keep the oil in the crankcase. Looking through forums it might be a seal between the Transmission case and engine case????. Typical Blow-By "Blow-by" refers to the amount of gas that makes it past the piston rings and into the crankcase. This will keep this debris oult of the crankcase. If you have a high crankcase pressure event, you could end up with oil coming out that line (maybe a lot). I agree that the breather could be overwhelmed if the mesh screen is clogged. Oil pumping out the catch can But if this is the issue then I can't see how oil can get out of the breather system at all. While running the buggy hard you could always smell oil vapor but never had oil come out of the filter. When the engine is off the PCV opens and allows the oil to drain into the pan. but none of the oil present is fresh oil nor is the oil pan coated. I recently replaced my cam and after I bolted it back up and started it oil is coming out of the crankcase breather. If oil is coming out liberally, there may be a worn valve retainer. It smells like oil when it gets hot. The seal rubber may and oil if a thread is smeared with them. Recommended crankcase pressure amounts vary depending on the type of vehicle and engine. When tipping the mower to clean the under side of the mower deck, tip it toward the oil fill plug or away from the crankcase breather. These gases carry some oil mist along with it. Because the hot oil in the crankcase is easily displaced by the increased pressure and because it has a perfect path out of the crankcase via the breather, the first sign of impending trouble is nearly always oil migrating into the air filter. As a result, instead of the oil mist being drawn through the airbox into the carbs and then burned off, the oil mist is simply spitting out of the breather onto your engine. Make sure the oil you are seeing is comeing from the crankcase breather. com - The Friendliest Tractor Forum and Best Place for Tractor Information. I agree that the breather could be overwhelmed if the mesh screen is clogged. Re: Engine oil out the breather tube in reply to M Nut, 09-11-2011 19:14:13 "engine lost almost all power and started dumping oil out the breather tube. It is a continuous stream. So I need some serious help here. To eliminate this problem and. I was able to use the blower over the weekend, but there was no EOD hill to run the blower up, which I suspected was causing some oil blow off. I have a 2008 ranger 500 EFI ranger. The breather is often located in the oil cap. It also seems to be coming out of the valve cover. I have a dual plane intake and a holley 750. UPR constructs the body of the valve with CNC machined billet aluminum for strength and durability that lasts. The breather is often located in the oil cap. Most four-stroke engines use a crankcase that contains the engine's lubricating oil, as either a wet sump system or the less common dry sump system. If you do find oil in your air cleaner it may well be that your PCV valve is stuck closed and is therefore not sucking the blow-by out of the crankcase but rather, it is blowing back into the air cleaner. 0 HP Self propelled/Mulcher lawnmower. It replaces the stock valve, and has steel reed valves, which vent the crankcase pressure to the cam chest, on pistons downstroke, and creates a slight vacuum in the crankcase, from the pistons' upstroke, to completely eliminate the pressures that force oil out the head breathers, base gaskets,air cleaner, etc. The system is not "doing its job" if it is blowing roughly half the crankcase oil out the breather every 1,000 miles. when the bike is runing oil spits out of the crankcase breahter hose. The water gets mixed with the gas, which causes the buildup and can increase fuel consumption in your. now if someone just knows the size of that. Another problem is low engine oil or low oil pressure. Then large amounts of oil (about a half a quart in around 20 seconds) started shooting out of the crankcase breather tube. Oil leaking from breather k301 I've been getting what I consider to be a lot of oil coming out of my breather. So I have a 2006 Honda CRF 250R, and it's leaking a significant amount of oil out of the crankcase breather hose. There also seems to be oil on the bottom left cylinder fins and linkage area, which lead me to think the OHV cover although that could be from the same leak. Re: 1994 Mitsubishi - 4M40 Engine Breather Blows Oil 12/11/2010 11:45 AM I also had the same problem with a 4m40 engine, thus i took off the rocker cover and flushed the breather with caustic soda and hot water, a lot of messy sludge came out of there. It smells like oil when it gets hot. S&S Crankcase Breather Valve For Harley Twin Cam A Motor Solves the pesky problem of oil carryover in Twin Cam "A" motors with the stock oil pump. The water gets mixed with the gas, which causes the buildup and can increase fuel consumption in your. help Polished Billet Aluminum; Includes 3/8 90 Degree Inlet; Excess Crankcase Vapors heart Vintage Gold Moroso 14 Air Cleaner $ 150. This stuck PCV must be sucking blow by gases that were heavy with oil vapors due to a engine mechanical problem. You should not be getting oil coming out of the breather cap. 2 but i put about 4. did not notice any smoke during. this is on a built motor and just recently got tuned. Don't check the oil immediately after coming in from a hard run. To prevent a vacuum being created, the blow-by gases are replaced by fresh air using a device called a breather. The air with the oil mist is coming out through. The fitting coming out of the crankcase has one side going to the intake tube and one side going to the PCV valve. The oil level is correct. On my Onan Marquis 7000, gasoline, 5 years old, there is a rubber hose (about 1/4 dia) that is a oil breather tube from the engine block to the rear of the air filter housing. The CCV Mod keeps this oil out of the intake plumbing and allows you to drain the collected oil off at a later date. Typical Blow-By "Blow-by" refers to the amount of gas that makes it past the piston rings and into the crankcase. The oil pump is the first to get any contamination and the influence from it. Onan motor spitting oil. Has hv oil pump that runs about 70 hot or cold. The breather is often located in the oil cap. It appears to be engine oil and upon inspection it seems the only place it could be coming from is the crackcase breather. Oil shooting out of your snowblower? How to fix - Duration: Oil out of crankcase breather fix Nate Sand. I think it's oil vapor. The agitation and expansion from running the engine would result in the oil/gas mixture overflowing out the breather. The problem is partially due to the design of crankcase breather. It's real purpose in life is allowing the crankcase to vent and then to return those vented gases to the combustion process for emissions control. You NEED a piece of hose on the breather so that if it pushes oil out it can have the chance to suck it back in as well. I pulled the recoil and the housing behind it thinking I would find where the breather came from. On most four-stroke lawn mowers, a small oil pump delivers oil from the reservoir to the crankcase and piston. Part of it may be that the previous owner who I bought it from might have overfilled the crankcase. This is maintained by the crankcase breather valve. Also none comes out while it is running. puff puff puff. Plugging the vent off is not an option, because the pressures inside the crankcase need a way to escape. Knowing what symptoms can be caused by crankcase breather problems can make repair a quick and easy job, getting your mower back into service without a lot of hassle or expense. Of course, if your air compressor is factory lubed for life (also known as oil less or oil free) you will not have an oil sump, and have no need of an oil fill tube. Since the channels are not sealed against the valve cover properly, the oil bypasses them and exits out the breather vent into the PCV system. It pushed the dipstick out, and oil came out, at higher rpm. The crankcase and trans breather has been relocated to the frame by the gas tank and uses a K&N filter. I read that the '91 is the only model where that hose clips to the Air Cleaner Housing. So if its no longer sealing it will be forced into the crankcase breather and into your front carby and start dribbling down your motor. It is a continuous stream. Then my mother asks me about the several black spots in the gravel driveway today so Im begining to wonder if something is wrong with my truck. A stream of oil, flowing from the engine's breather tube and into your motorcycle's air box, is the result of a condition called blow-by. Oil from all the engine is collecting in the crank case during bike is stays long period and when you starting the bike extra oil is starts leaking from the crank case breather. The engine is worn. I know the breather was connected to the carb so any emissions were burnt off but I have twin dcoe's so the breatehr has a wee K&N type filter on the end. If the pc vale is plugged it will cause the crankcase to pressurize and blow oil out the breather hose and dipstick tube. Plugging the vent off is not an option, because the pressures inside the crankcase need a way to escape. My dealer told me that it's totally normal and everyone complains about it. To eliminate this problem and. It is very important to have adequate crank case venting on turbo motors. This pressure encourages oil leaks through the gaskets and contributes to air pollution by sending a constant stream of untreated oil vapor steaming out of the engine's breather cap. I thought maybe the piston rings could be bad creating too much crankcase pressure. It should not have any type of significant oil drainage. The very nature of the air oil seperator is that it returns oil to you crank case that would have otherwise went out the breather tube. A certain amount of cylinder pressure will always find its way into the oil pan. This leads to the suggestion that the rubber hose ought to not be pointing towards anything which the rider does not wish to have covered in oil mist. Oil coming out of the breather tube My Dad has a 1999 model 2500 with the Cummins 24 valve under the hood. With the motor warm pull the breather and see if it's puffing smoke. The factory breather on the tappet cover can become gunked up over time as well and cause crank case ventilation problems. Re: White Smoke and Oil Emissions From Crank Case Breather on Diesel Engine 02/24/2015 2:35 PM If droplets of oil gets blown out at the breather, the crank case has too much oil in it or compression is leaking past the pistons. Recommended crankcase pressure amounts vary depending on the type of vehicle and engine. I changed my pcv valve and the problem went away. A small engine breather valve is a one way check valve. I had oil blowing into my intake from crankcase breather. 50 over, I also disconnected the tores. Once you switch to an open filter, you are left with a hose coming from the vavle cover's vent that has nowhere to go. I am leaking oil out of the crankcase breather and bad. So if you are blowing oil out of the breatherthose are the most likely causes unless someone WAY overfilled the crankcase with oil after your last oil change. If you can, disconnect the breather hose and push it into a tall bottle with a narrow throat, such as a coke PET bo. If you have a vacuum leak, you may have a bad PCV valve. My motorcycle has an oil leak from the breather pipe pls help? hi all , i have a yamaha xj 600 n and after a ride of 25 miles or so when i switch off the engine it gushes oil out of a breather pipe between the engine and the rear tyre. I recently replaced my cam and after I bolted it back up and started it oil is coming out of the crankcase breather. oil coming out breather hose need help when the bike is runing oil spits out of the crankcase breahter hose. It was blowing oil so badly out of the rubber hose that it blew the tube right off the side of the carburator. With new oil filling the Cartridge and the Old oil not being removed, the oil pressure builds up in the cartridge and is forced out the seals. When an after market Air cleaner is installed, typically with two plates and a filter, that filtered air connection is lost. This was Oil leaking out the cone filter onto my exhaust mani and intake. This pressure encourages oil leaks through the gaskets and contributes to air pollution by sending a constant stream of untreated oil vapor steaming out of the engine's breather cap. I had white smoke coming out of my breather on my falcon a couple years ago. If you have blow by meaning gas is going around the piston into the crank case, this will cause positive pressure in the crankcase. I'm thinking that the breather tube needs to be much taller and more vertical and this will help keep the oil in the crankcase. Do NOT drill a hole in the crankcase!. The hose from the air filter to the motor is to let filtered air in. Once there, the only way it can get out is through the drain tube on the bottom. This is basically when you have too much oil in the bottom of the crankcase and it either blows out the breather or the flywheels throws it up on to the piston skirts and the motor smokes like hell or both. Re: White Smoke and Oil Emissions From Crank Case Breather on Diesel Engine 02/24/2015 2:35 PM If droplets of oil gets blown out at the breather, the crank case has too much oil in it or compression is leaking past the pistons. Your breath will come out the oil filler cap hole in the valve cover. I think I do not have enough crank case ventilation. Make sure to check the PCV Valve before overhauling your engine!! Here's a trick that one of my readers suggested. Of course, a direct contributor to oil windage is excess/over-filled oil levels. The only other thing that I can come up with is that there might be something plugged or wrong with the baffles in the valve cover that separate the oil from the air coming out of the breather tube. 2) We checked the engine breather and no oil was coming from there nor was any blow by when revving. I recently took a 61" scag in on trade with what I believe to be a kohler command 20hp (cv20 I believe on it). If earlier engine, it will be the ONLY open large diameter (3/4- 1") hose coming down from the engine. This will keep this debris oult of the crankcase. I noticed we're getting some blow by coming out of the crankcase vent tube. How much oil did you put in the engine when you changed it? This engine should take around 48ounces of oil. This pressure will vent wherever is the easiest, in your case the valve cover. As blow-by saturates the crankcase atmosphere with super-heated oil, it chokes the air inside the crankcase, coating the crank, rods and pistons with a heavy layer of lubricant – far more than these parts need. oil coming out breather? Post by fish » Mon Jun 04, 2007 7:51 am im looking at buying a 89 bighorn. I also rechecked the oil level in the light (usually it's dark when I check it). 9 cdti (Z19DTH) oil hose, 1. UPPER CRANKCASE • Remove the breather cover 1. It works by allowing high pressure to escape the engine crankcase, but close when crankcase pressure is lower than the outside ambient air. this build has less than 3 hrs Oil coming out crank breather - Honda TRX Forums: Honda TRX 450R Forum. So I've noticed every once in a while when I park my bike and return there is a small area of oil right beneath the 3 breather tubes. I ran my breather filter over the engine and down low and hasn't been an issue. it doesn't always burn oil when the rings are bad. it could have a bad set of rings. Since I have had this Yamaha Timberwolf it has had the problem of blowing oil out the breather, Also if I am running it down a road and look back I can smell oil, So I assume its burning it as well, Plug is a light brown in color. If you are getting an excessive amount of air/oil coming out the breather vent it is an indication that your rings are shot. Engine manifold vacuum sucks fumes out of the crank case, fresh air goes into the crank case through the non-vented oil filter cap. Troubleshooting A Crankcase Breather That Is Blowing Oil If your crankcase breather is passing oil, chances are that something's wrong (Okay, we know something's wrong, but don't be too alarmed). 5 race weekends since then. that the cone is wet with oil and dripping down onto the exhaust. Crankcase Breather allows pressure which may build up in the oil pan to escape. I have never had this problem before. A gathering place for all Farmall Cub, Cadet owners and tractor enthusiast from all over the world. Oil carryover is the oil that comes out of your breather and ends up all over your bike. However, I had a lot done during that rebuild out of pure frustration and fear of being stuck in the middle of nowhere ( 124 cylinders, cam, new oil pump/plate , breather Cap, and yes, somewhere a long the way I started using less oil as well) and the bike runs great 3000 miles post sumping. Running 2200 rpm they have much less breather drip (blowby). If you have a high crankcase pressure event, you could end up with oil coming out that line (maybe a lot). I am leaking oil out of the crankcase breather and bad. Clogged or worn out breather parts can lead to a blown gasket or seal. The primary one is a hose at the front of the motor just under the oil filler cap. I'm not all that surprised. During acceleration the compression of the engine will push oil past the rings, into the crankcase. 004 for both the intake and exhaust. This pressure will vent wherever is the easiest, in your case the valve cover. The engine puts out plenty of power. As a engine runs the crankcase will build up air pressure and that tube vents it into the air cleaner. Now, since the 5/8" hose feeds in from the crankcase block breather adapter, as too does the 1/8" id. as if the crankcase is building up more pressure than normal, and the oil has nowhere else to go. timing could be off a tooth but it wouldnt run right. Most four-stroke engines use a crankcase that contains the engine's lubricating oil, as either a wet sump system or the less common dry sump system. If it is like most Tecumseh engines, the breather tube is coming out of the valve cover. As the engine warms up the oil expands and build up pressure in the crankcase and if the hose is pinched it build up enough pressure to blow the seal out around the shift lever. Yuck, what a mess. The oil breather hose attaches between the air cleaner housing and the rear cylinder. everytime i park my truck, overnight it leaks a couple drops onto the driveway out of the crank case tube, what could cause this? and how could i fix it? all i can seem to find anywhere is people posting about a huge load of oil comin out, mine is barely anything, but still noticeable when theres black spots all over the driveway, any ideas? thanks. Overfilling the crank case is the most likely cause of your problem. It was soon discovered that by cutting the end of the road draft tube at an angle and extending it into the airstream below the car an actual flow of fresh air could be created through the engine by providing an inlet breather, often in the form of an oil filler cap with a coarse mesh filter material, which acted as a flame arrestor and kept bugs out of the crankcase. The oil and vent lines are hooked up correctly and was running fine like this last year. While running the buggy hard you could always smell oil vapor but never had oil come out of the filter. The engine is worn. The crankcase breather, located inside the engine, is a pipe which releases gasses trapped in the engine compartment. However, now i have a significant amount 10-30ml or so every ride. My bike was having problems with blowby, and continued to blow some oil out of that breather tube coming from the rear cylinder (the positive pressure tube). that is your crankcase breather - if it's blowing oil bad that could be a problem - does your engine have a lot of blowby with the oil cap off? any oil coming out. Then my mother asks me about the several black spots in the gravel driveway today so Im begining to wonder if something is wrong with my truck. As a engine runs the crankcase will build up air pressure and that tube vents it into the air cleaner. What would cause oil to blow out the breather on a Harley Davidson Unless there is a bunch of oil coming out, it's not a problem Excessive crankcase pressure will cause this problem two. Oil coming out the crank case vent has two very common causes, and a couple not so common ones. If there's not a great reason or need for the breather, I might do away with it myself (PCV actively pulls acidic vapors out of the crankcase, whereas a breather just lets the stuff ooze out when pressure builds). I'm not saying he's wrong cause i don't know much about that stuff. As for the Uni Filter:Godawful things, just be sure to keep it oily. I also rechecked the oil level in the light (usually it's dark when I check it). I had a similar problem with my 300C - found the line from the PCV to the intake was kinked, causing oil to blow out the other side of the engine through the breather tube. I have a GY6 late model 150cc 4 stroke scoot and I have oil coming out of the hose that comes from the top of the motor and goes to the air cleaner box. The engine is in a Cub Cadet 582 and the oil collects in the air cleaner pan. The sump outlet is below the scavenge pump inlet so the oil has to flow uphill to get to the pump to return to the oil tank. Anything below 120psi is suspect, according to the factory manual. Yesterday evening I noticed oil everywhere under the truck, even on the bumper and tailgate. Well I just started working on the bike to replace the Reed Valves and I came across the Crankcase breather hose. I'm thinking there should be a T fitting, elbow or whatever in the line near the engine to which a breather hose runs to the oil tank - which is the frame. Two modifications in mind:. this is on a built motor and just recently got tuned. When an engine develops a hole in a piston, that cylinder then acts as a syphon rather than a pump. Instead, I pull out the oil dipstick and insert the tube from the Engine Saver into the oil fill port, pushing the supplied wider foam rubber grommet past the breather tube inside the oil filler. When the rings were bad enough to cause pressure that low, it would be blowing lots of gray smoke out of the crankcase breather pipe and oiling up the air cleaner(s) in a matter of minutes. you crankcase breather is probly frozen off, not sure were it is located on your vehicle but there should be a hose comming out of a vavle cover that goes into the intake may need to pull it off and check for a restriction. it doesn't always burn oil when the rings are bad. Of course it did not blow oil while they had it. You don't need a breather. Yamaha got complaints about excess oil coming out the breather and revised the oil level in '75. Plugging the vent off is not an option, because the pressures inside the crankcase need a way to escape. Crankcase emissions or “blow-by” as it is commonly referred to, are the gases and hydrocarbons that are pushed out of the crankcase during engine operation. the first ones are the gentlest and safest, the later ones are more risky. Here are some common causes of blow-by and excessive oil consumption and how you can avoid them on your next engine build. Knowing what symptoms can be caused by crankcase breather problems can make repair a quick and easy job, getting your mower back into service without a lot of hassle or expense. What you need to do, just collect that oil coming from breather into some storage pan and ride the bike untill leaking will stop itself. In the end the mistake was the "missing" hole in the gasket on drive side crankcase to let the brather air free to the chaincase! I send a photo of a 4 spring breather disc. Plug hole number 4 was stripped out by the previous owner.