Yes to "drains back into the motor".

The horseshoe setup will work. The only thing I don't like about those types of setups is all the places where there is potential for leakage. I prefer the solid backing plate setup as shown in the attachment.

 

Internesting. I assume that backing is just drilled and tapped for those hose nipples. A banjo bolt and a sealing washer on the outside? Or something funky with the stock breather bolts? What did you do to fill in the channels for the typical rubber breather passages? Silicon or permatex? I have a very similar unit I could mess with and save some money...

 

The holes are drilled into the breather/mounting bolt cavity; just have to be careful not to let the threaded part of the nipple go deep enough into the cavity to interfere with the breather/mounting bolts.

I would have to see which plate you have to answer your question regarding blocking the passages for the internal rubber breather hoses. I would not use silicon or Permatex for fear of something coming loose and getting into the motor; bad juju! There are several ways to skin that cat; if you can find a way to cross drill and tap for a pipe plug or use JB Weld; that is what I would suggest.

I have attached a link from another forum where I spend a lot of time. Overkill for what you are doing but I think the photos will help you figure out how to make your backing late work.

http://harleytechtalk.org/htt/index....c,50630.0.html

 

Awesome, thanks. This has decidedly made me trash all my previous ideas and go grab a 'ness big sucker with the internal breather passages and plug em up, drill and tap for the nipples and be done with it.

 

djl, you go way over the top.

Again lots of good threads & pics to do this. Sounds like you will drill & tap, if you do don't tap too deep and be sure to measure out so there are no other mounting problems. See the difference between djls mounting plate and the one I posted. The nipple posts angle toward center slightly more on mine, either is fine depending on the AC you have but I could have angled mine in more and would have made the lines all but visible w/my SEHB. Also those 1/4" nipples are pipe thread and require pipe thread tap vs standard.

 

...over the top Djl...
amazing what a careful review of the HD TC oiling system diagram clears up almost immediately... literally the picture = 1,000 words quip.
I've used the modded backing plate vent to earth system on my last three bikes... works great--clean intake; and best of all clean mist-free air to the engine

 

First of all, we are not talking about a great deal of oil, unless there is something amiss with the engine or maintenance of the engine.

If your bike is puking so much oil that you "need" a catch can.... Not that catch cans can be nice additions of chrome or other bling, but if a bike is spitting so much oil that a simple hose and filter cannot absorb it without dripping or spraying the bike, something is wrong.

Read this thread on the subject-

https://www.hdforums.com/forum/oil-a...f-my-bike.html



Regarding going back into the engine...

Yes, if running the Outlaw Breather Bolts, or a Traditional Hose & filter going above the carb or throttle body, or a horseshoe set-up going above the carb or throttle body, any oil not absorbed by the filter or expelled in a fine mist will run back into the engine when it is shut off.

It runs back into the passageway/channel on the outboard side of the umbrella valve...not back into the pan or tank.

HOWEVER, it does not just blow out when the bike is started up again. There is always some oil sitting in that passageway, and some of it gets pushed out to whatever external breather system you have (or into you throttle body and combustion chambers if you don't have an external system) and dealt with in the same manner as always.

But some/most of it is heated up to become a vapor and expelled as a vapor. I suppose if a person never got their bike up to operating temperature for a 3000-5000 mile period (lots of really short trips), then there would be a possibility of that passageway and hoses or horseshoe filling up...but that would be the least of your problems....

The reality is, that once the bike is at operating temperature, most of the oil that is getting past the umbrellas gets vaporized and expelled that way. So any little bit that drains back into the engine, sits there with the other oil that is already there and will get expelled as a vapor the next time the bike is ridden at operating temperature.

We have a good selection of External Breather Systems that can be seen at this LINK.

These is not a new concept. I am 57 and when I was a kid we were running horseshoes and hose & filter external breather systems, thus the name "Traditional Hose & Filter External Breather System".

 

I once started my twin cam to move it with no air cleaner assy. and open breather ports. No oil came out and very little air if any with a cool engine at idle. I expect there would be some blow by under hard acceleration. Unlike a car that has PCV going directly into the intake manifold along with any oil mist or moisture the only way the Twin Cam has to vent the crank case is through a port in the side of the head and into the intake stream. It seems to work well but some air filters will get saturated with oil and drip. Mostly the stage I type with open elements.
Billy

 

There are a great many air cleaners that successfully get all the oil and hot, oxygen depleted air into the throttle body, thereby REDUCING performance and engine longevity more efficiently than those that only get some of it in, and some onto the filter.

It is Always Better to have an External Breather System (EBS), no matter what Air Cleaner you're running.