Sportsters vent their rockerboxes into the airbox. Why? It gives a chance for the oil vapors to be combusted along with the gasoline instead of being vented to the atmosphere.
Quick rundown on pressures. High pressure likes to flow to low pressure. That's what makes sucking soda through a straw work. Well, the crank case of a sportster is pretty high pressure. When combustion happens in the cylinder, a small amount of the combustion gases leak past the rings into the lower parts of the engine, increasing the pressures there. These over pressures are moved up the pushrod tubes to the rocker boxes. Now you have higher pressures in the rockerboxes.
Where do the rockerboxes vent into? The air box. The air box has the engine sucking air out of it. This makes a low pressure.
Boom: High pressure to low pressure.
When you rev the throttle or even let it run steady on the interstate for a while, you allow the pressures to pull more oil out of your rockerboxes into the air box, saturating your air cleaner, and later in really kickin' engines, your pants leg.
How do you fix this? Well, going with a K&N filter set up (aka Screamin' Eagle Air Cleaner) is a good first start, 'cause those air elements can be cleaned. There are other solutions that have been tried like boring out (slightly!!!) the oil return port on the rockerbox. You can also put on a "horseshoe" that plugs the ports into the airbox and vents the rockerboxes to a small hose with a filter added to the end.AnswerAn overfull oil tank will do it. Even if not overfull just about all harley's will blow oil out the air filter. Unless there is a bunch of oil coming out, it's not a problem
What I've found is that the air filter eventually gets saturated and then starts to leak through. The level in the oil tank doesn't seem to matter. If you change the air filter the problem goes away, until the new one gets saturated and then it starts all over again. My plan is to get a K&N air filter, which you can clean yourself and save having to buy a new air filter every 4,000 miles or so.AnswerI had a sportster 1200 custom and now have a 85 wide glide and i can tell you keep from Twisting the throttle to much and you will notice less oil in the filter. The answer takes the fun out of Harley's but it blows oil when your wrapping it out for fun. If a person stays off the throttle you will notice that the filter will not have near as much oil in it.
A clogged tappet screen.
Buy a oil breather kit if you dont burnt oil will build up on top of the piston fauling out plugs and giving bad gas mileage and if its carberated it will clog up the carb !
It's a Harley. Notorious for hard neutral.
It can happen if bike has not been started for awhile. Oil leaks past check ball in oil pump.
Take it to an experinced mechanic and do not pass go!
Change out the intake Gaskets and Carb. Gasket. You have a vacuum leak.
I have a 92 Tour Glide that was doing the same thing. It is most likely the oil pump check valve is either bad, stuck, or has build up of gunk on it. I took the external breather off and ran a long hose from it straight up, with the bike running and the breather on the end of the hose until it stopped blowing out. Then I changed my oil. Hope this helps. There is a Plug by the back push rods, remove the plug there is a screen under the plug. Clean the screen and reinstall it. this will fix you problem.
If by breather you mean the air filter......yes.
probably a bad spark, itll cause your engine to misfire flooding petrol in without igniting it, when it sparks afterwards it ignites causing a bang and backfire.
The most common cause is a grounded stator. Lack of primary oil or a too-tight chain can also cause excessive chaincase heat.
I would check the wire connections under the right side tank. I know on my 78 FLH I had that issue and it was the wire on the wiring block that was bad.
Yes. And unless you're made of money, Mobil 1 15W50 will work just as well as their V-twin specific 20W50 at a considerable savings. --- Some detractors will say auto oil containing moly will cause slip in the primary. Mobile 1 15W50 oil does not contain nearly enough moly to cause this to happen, and can be used in all three holes of your Harley Davidson with superior performance. Word of warning - Some service managers may use this as an excuse to void your warranty, so if your Harley is under warranty it is probably best to simply use Mobile 1 V-Twin 20W50.
It sounds to me like the clutch adjustment isn't correct. If the cable is too tight, it will cause the bearing to spin continuosly causing it to wear out prematurely.
pcv is bad.
It could several things. Work from the spark plug, to the plug wire, to the coil until you find the culprit. If the coil is good then it could be the ignition module. The coil is the most likely problem but the plug or plug wire would be the preffered problem.
they wore black cause that was the color the company picked
Valve cover gasket.
I was told by my Jaguar dealership that it can be either "a clogged breather tube can cause that to happen, but it can also be an issue with the throttle body."
The Gaseous buildup inside of the internal combustion chamber would cause engine failure, the engine to blow, and explode litterally
I thought I had high oil pressure, When I would rev the engine the oil pressure would max out on the oil pressure guage. Luckily it just turned out to be loose connections to the oil pressure sensor. I tightened the terminals and the problem went away.
intake manifold leak
cause of death for jackie lee davidson feb 18 , 1995
yes. if the valve is plugged or stuck closed, oil can be sucked into the intake through the pcv breather.
I Have the same issue. Red Light on the speedo stays on. It seems to refer to an electrical problem. Ive discovered that my brake lights dont work sometimes. Could be the cause. Im off to HD today. 2012 Dyna FXDWG
Yes, it could.
Excessive crankcase pressure will cause this problem two possible causes are worn/broken piston rings or a blocked engine breather.