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

[Hossamania]

Thanks Mike, that's what we're thinking too.

[Hossamania]

He took a ride on it yesterday, only the rear cylinder is dumping oil after he parks. Couldn't tell if it was dumping while riding, he was going to crawl under it when he got home (too hot to crawl under in the parking lot).
Going to change the rear breather in the rocker box, check for any blockage, if that doesn't work, it's probably the rings. Yay.

[Ohio HD]

But he said 5% leak down. Doesn't sound like rings are letting pressure through.

[Hossamania]

But he said 5% leak down. Doesn't sound like rings are letting pressure through.

I agree, it's going to take some investigating.
It runs damn strong for a 107, 121 ft/lbs.

[Hilly13]

Oil ring spring maybe?

[Hossamania]

Oil ring spring maybe?

Quite possibly. Going to try a couple things (new breather valve), if no love, probably a tear down this winter.

[Hilly13]

Oil ring spring maybe?

Quite possibly. Going to try a couple things (new breather valve), if no love, probably a tear down this winter.

That blows Hoss, hope it's something easy.

[Tacocaster]

More so a question than a suggestion.....would draining the oil (at operating temp) with the oil filler cap on-tight and watching the flow out of the drain indicate a bad breather valve/assembly as it can with TC engines?

Might save some repair anxiety (oil ring spring versus a breather valve repair).

[louloupa]

I modified the ventilation on the transmission housing. The same system as trask but for $20. I have the latest oil pump update. I don't fill more than half the dipstick with oil when hot.
Conclusion, not the slightest trace of oil in my filter and the TB. No need to reroute the breather outputs

[Hossamania]

Even in a perfect world, I'm not a fan of the stock breathers running into the throttle body, I've seen the film of oil that collects on it.

[chas]

I purchased a billet external breather from DK Customs that hangs below my ac. Was an easy install and seems to work ok. Probably have to empty once every oil change or 5k miles.

[Hossamania]

I figure God made the oil, he can have it back, I send the overflow right back to the ground, whence it came.

[IronButt70]

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....

Pretty much the exact same setup I used on my TC except I use a catch can. Get about 2-3 ounces of nasty looking oil condensation mix between oil changes. Used Permatex gasket maker to fill in the vent holes to the intake. Hardens with engine heat but can be removed if ever needed.

[Hossamania]

A little more info, it seems when the parts showed up, the package for the oil pump was open. The guy working on it assumed the owner had opened it when it arrived (parts came to the owner, dropped off with the bike when ridden to the installer's house), but that was not the case. HD shipped an open package and oil pump. Is it correct, a water cooled oil pump instead of oil cooled? Was it installed, removed, cleaned up and returned? So now there is question if it is the correct oil pump or not. Plan now is to replace the pump and breather. If that doesn't solve it, tear down imminent.
Bikes are fun.

[Hossamania]

Might have found the problem.

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[Hossamania]

It was recommended by one of the performance vendors to use two o-rings to take up the excess play in the stock set up. Only one will be used for this install.

[rigidthumper]

Two orings are fine, as long neither are cut

[Hossamania]

Yeah, that can be an issue! He popped them on with one, said it installed smooth, no binding. Pretty sure it will work far better than it was.

[Fugawee]

Nice Catch!

[Hossamania]

Now the question will be if the owner wants nice neat internal breather tube setup, or go with the external breather tubes.
I'm pushing for external. But too often from over function.

[FSG]

help him spend his money .....

[Hossamania]

I think two new ones were put in. At $14, very easy decision. Fueling wanted $500. Yeah. No.

[Ohio HD]

T-man would be my choice.

[FSG]

still $uper $pendy   

[Hossamania]

still $uper $pendy   

Yeah they are!

[IronButt70]

still $uper $pendy   

Yeah they are!

Looks like an old 2 cycle outboard motor reed valve. 

[Hossamania]

Back to normal. New breathers in, all bolted back together, barbs and external hoses installed. Waiting for the RTV plugs in the old breather passages to dry, then a test ride. Fingers crossed.

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[Hossamania]

Success! 20 mile ride, combo of city, hiway, and extralegal speed, dry as a bone.

[nibroc]

    

[Hilly13]

Good job Mr Hoss 👍