Many bikes never leak any oil out of the breather bolts, or filter element.

However, ALL bikes have hot oily air coming out of those breather bolts and being fed thru the throttle body into the combustion chambers.

This is Not good for engine performance or longevity. Check out the pictures below.

Internal combustion engines, including the Harley engines, run better on cool dry air and gasoline. When you add the crankcase, oxygen depleted air, along with the oil in it, (from the breather bolts) performance suffers, along with the longevity of your engine.

Take a look at the pics below-







And here is a chart that shows the performance difference-




It is always better to use external breathers, both for your bike and for performance. Click HERE for more info on external breather kits.

 

Is there a dk customs kit for use with hd screaming eagle back plate?

 

Yes, the Discrete Head Breather System at this LINK will fit.

 

Where does it exit from?

 

Alright...

Ive got this AC.

http://www.arlenness.com/prodcat/Air4.asp

Im not exactly sure what the breather concern is.

Does oil come out of the AC because of pressure? And the breather kit relieves that pressure? Or just gives the oil a place to go instead of the combustion chamber?

Where does the oil travel through to get out of the case, into the intake?

Can someone make it stupid simple for me? Appreciate the tolerance.

 

The crankcase breather vent system simply relieves pressure created by the bottomside of the pistons going up/down, (Think air compressor) So.It has to go somewhere. HD's answer to comply with EPA regs vents that pressure combined with oil and water vapor that condenses inside the cases back into the the throttlebody and your combustion chamber. Not good for your motor IMHO.

 

Thanks much Stover.

 

How does the dk customs systems get it out from behind the breather? I must be missing something because I'm not seeing on my bike where that hose is gonna be able to come out.

 

Copied and pasted my solution from one of the many threads about crankcase breather venting.

This is what I came up with after being unable to find any system that would work with a SE stage one backplate, I went with dual hoses parallel to bottom of rocker box covers then down to hidden catch can in cowbell. Marine shrink wrap over fittings tapped into backplate really cleaned it up.










This is why. I didn't have a lot of oil drippng, But enough to make a mess on cam cover,pipes,side cover,and front of saddle bags if I didn't clean the filter every week or so. It looks like this because the moisture and oil are being shaken like a paint mixer in the cowbell. Glad this gunk isn't going in my intake.

 

I noticed the same thing. When I put on my home made breather kit I put a clear filter on the end of the hose and noticed it only had condensation in it. At that point I was running the oil half way between full and add.
After changing the oil and filling it up to the full mark I got oil sludge in the clear filter. I don't like that too much.
From now on I am only filling it to half way between full and add. As long as you are above the add mark the level is ok. Just keep an eye on the oil level. ( oh yeah, you are supposed to do that anyway! )