External breather setup

[Hossamania]

2018 Ultra Limited 107
Anybody got any ideas on how to clean this up, a system that will work with the S&S air filter? The original setup was allowing far too much oil into the filter after a cam change (RS468, he loves it). A breather oil cap didn't solve the problem. CCP and leak down test good. Put the old breather bolts in for now, seemed to work better, and pushes any extra to the ground.
Looking for something that might look good and work well.


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[Ohio HD]

What PSI is getting bled off when leakdown is tested?

[Hossamania]

A friend is working on it, waiting to hear back, but he sent me these.

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[Ohio HD]

So 5 psi over 100 psi, or 5%. That's a good test score.

I have the same tester from Lang.

[Hossamania]

It seems the engine is plenty healthy, not a lot of miles on it, cam got changed last week, it puked oil out the air filter all day on a 100+ mile ride. We pulled the oil filler cap and stuffed a rag in there to simulate a breather cap, didn't seem to help. He now has a proper breather oil cap, and this temp setup seemed to take care of the issue. I think the air intake was pulling a lot of vacuum thru the head breathers, trying to eliminate that, go full external.

[Hossamania]

The other thought was to drill and tap a couple holes for barbs and plug the passages going to the inside of the filter, run the hoses down to the ground, old school style fix.

[Ohio HD]

Might be sumping and blowing out the breathers. I think it was mid-year 2019 when HD started with the latest oil pump.

[Hossamania]

Pump was changed to the 2020 part number. Only 2 ounces of oil came out the engine plug, so sumping doesn't seem to be the issue.
Also, the motor had 5 quarts of syn oil, it got changed now to 3.5 quarts conventional oil, and will figure out an external breather system. Take it for a good long ride and see what happens.
One thing my friend mentioned that's working on it is that maybe one of the cylinder head breathers is acting up, maybe stuck or defective. Stock one is $14. Fueling is $500. Will go stock if found to be defective!

[Ohio HD]

Test the breathers. But they generally fail and let atmosphere back into the motor. You want them to expel pressure. It just so happens that there's excessive oil mist coming out with the pressure.

The breathers never stop pressure from leaving the motor, only the reverse.

[Hossamania]

Agreed, they are definitely letting it out!

[Hossamania]

It's much better, when the owner, another friend, dropped it off, it puked oil on a short 10 or 15 minute ride. When the mods were done, 3.5 quarts, external hoses, it didn't puke a drop after 20 minute ride. So for now it seems working, just want to set up a decent looking hose system. Thinking cheap easy setup might be barbs and hoses, JB Weld the internal passages in the backing plate.

[pendo31]

I found that vented dipsticks don't work very well, Trask makes a vented transmission cover for M8s that seems to solve that problem or you can look up a youtube video that shows how to do it for around $50

[Hossamania]

I found that vented dipsticks don't work very well, Trask makes a vented transmission cover for M8s that seems to solve that problem or you can look up a youtube video that shows how to do it for around $50

How does a vented transmission cover help with engine oil pushing out the head breathers?

[FloridaJim5]

I found that vented dipsticks don't work very well, Trask makes a vented transmission cover for M8s that seems to solve that problem or you can look up a youtube video that shows how to do it for around $50

How does a vented transmission cover help with engine oil pushing out the head breathers?

There are two chambers under the cover.  One side is the trans vent and the other side has a vent between the oil tank and engine.  If you vent the engine side of the cover, the oil tank/pan is vented to atmosphere. 

[Hossamania]

Thanks for the info, hadn't seen that, or maybe wasn't paying close enough attention, in discussions on this site.

[pendo31]

It's only possible with 2017 and newer

[FloridaJim5]

Thanks for the info, hadn't seen that, or maybe wasn't paying close enough attention, in discussions on this site.

Very good explanation of the venting on the M8:

[JSD]

It is made of plastic Hoss . Didn't watch video as  seen a trask.

[hattitude]

It's much better, when the owner, another friend, dropped it off, it puked oil on a short 10 or 15 minute ride. When the mods were done, 3.5 quarts, external hoses, it didn't puke a drop after 20 minute ride. So for now it seems working, just want to set up a decent looking hose system. Thinking cheap easy setup might be barbs and hoses, JB Weld the internal passages in the backing plate.

That's what I do on all my Twin Cams. The only difference is I tap the holes in the back plate. I believe it takes a 6mm tap. I then put a 6mm set screw in the hole, slathered in JB Weld.

[Hossamania]

It's much better, when the owner, another friend, dropped it off, it puked oil on a short 10 or 15 minute ride. When the mods were done, 3.5 quarts, external hoses, it didn't puke a drop after 20 minute ride. So for now it seems working, just want to set up a decent looking hose system. Thinking cheap easy setup might be barbs and hoses, JB Weld the internal passages in the backing plate.

That's what I do on all my Twin Cams. The only difference is I tap the holes in the back plate. I believe it takes a 6mm tap. I then put a 6mm set screw in the hole, slathered in JB Weld.

This is an S&S back plate, haven't looked at it for what it will take to plug it, but it shouldn't be a big deal. I did think about tapping and plugging, just haven't put eyes on it. Hopefully my buddie that's working on it will get it figured out before I get there to offer criticism and ask him why he did it that way. I'm helpful like that.

[guydoc77]

Hoss, I have the same AC and backing plate.
I used black RTV in the holes, worked it in with a small zip ties and pressed it in so flat at the surface.
It has held up fine for about 20K miles.

[Hossamania]

Thank guydoc. I'll pass it on.

[hattitude]

It's much better, when the owner, another friend, dropped it off, it puked oil on a short 10 or 15 minute ride. When the mods were done, 3.5 quarts, external hoses, it didn't puke a drop after 20 minute ride. So for now it seems working, just want to set up a decent looking hose system. Thinking cheap easy setup might be barbs and hoses, JB Weld the internal passages in the backing plate.

That's what I do on all my Twin Cams. The only difference is I tap the holes in the back plate. I believe it takes a 6mm tap. I then put a 6mm set screw in the hole, slathered in JB Weld.

This is an S&S back plate, haven't looked at it for what it will take to plug it, but it shouldn't be a big deal. I did think about tapping and plugging, just haven't put eyes on it. Hopefully my buddie that's working on it will get it figured out before I get there to offer criticism and ask him why he did it that way. I'm helpful like that.

FWIW.....

Here's the external breather hose on my S&S Stealth Air Cleaner for 58mm throttle body.

I labelled the pic, to send to a friend after a discussion with him about the same mod....

[HogMike]

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On my M8.
Similar setup on th twin cam and my evoYou cannot see attachments on this board.

[HogMike]

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On the evo