Homemade external breathers - hose size to fit breather bolt nipples?

[BrianK]

Title pretty much says it all; I'm thinking about fettling together an EBS for my 06 Deuce.  I have a K&N 3909 on there and thinking I could run hoses from the breathers to a T- or Y-connector and then drill a hole in the backing plate to run the now-single hose out of. 

I'm thinking of using clear plastic tubing so I can see what's coming out of there, and probably starting without a filter or catch-can unless and until I see a need to add.

I'm not looking for any power gain; more concerned with venting oily mist back into the combustion chambers to create more carbon buildup.

Anyone know what internal diameter hose would work for this (and/or any other suggestions)?

Thanks folks - BrianK

[RoadKingKohn]

Title pretty much says it all; I'm thinking about fettling together an EBS for my 06 Deuce.  I have a K&N 3909 on there and thinking I could run hoses from the breathers to a T- or Y-connector and then drill a hole in the backing plate to run the now-single hose out of. 

I'm thinking of using clear plastic tubing so I can see what's coming out of there, and probably starting without a filter or catch-can unless and until I see a need to add.

I'm not looking for any power gain; more concerned with venting oily mist back into the combustion chambers to create more carbon buildup.

Anyone know what internal diameter hose would work for this (and/or any other suggestions)?

Thanks folks - BrianK

I used a 1/8 NPT. Size the hose to fit.

[Ohio HD]

Title pretty much says it all; I'm thinking about fettling together an EBS for my 06 Deuce.  I have a K&N 3909 on there and thinking I could run hoses from the breathers to a T- or Y-connector and then drill a hole in the backing plate to run the now-single hose out of. 

I'm thinking of using clear plastic tubing so I can see what's coming out of there, and probably starting without a filter or catch-can unless and until I see a need to add.

I'm not looking for any power gain; more concerned with venting oily mist back into the combustion chambers to create more carbon buildup.

Anyone know what internal diameter hose would work for this (and/or any other suggestions)?

Thanks folks - BrianK

Most hose barb fittings will be 1/8 pipe thread (1/8-27 NPT). The drill bit size is a 21/64" or close to 0.329" as you can get.

Hose size, either 5/16" or 3/8" is ample for a crankcase breather.

[BrianK]

Thanks folks.  I've been hearing/reading anything from 3/16 to 3/8, with votes for every teenth (and a
 few 32nds) in between.

Focusing on the breather bolts, I'd kinda forgotten the hose has to fit the T/Y fitting also....

[fbn ent]

Somewhere here is a post (mine) with many examples of things that guys have done. Damned if I can find it now though...

[Hossamania]

Many threads on external breathers, a search will find quite a few.
This one is recent, not exactly your setup but has pics for ideas.

https://harleytechtalk.com/htt/index.php/topic,120515.0/all.html

[Hossamania]

This one has a lot of info

https://harleytechtalk.com/htt/index.php/topic,110208.0/all.html#msg1328784

[BrianK]

Thanks!

[BrianK]

I just did the work.  2006 Softail Deuce with K&N 3909 air cleaner.

Ran 5/16" (ID) clear tubing from the breathers (secured with worm clamps) to a barbed Y fitting with one arm of the Y projecting through the backplate (toughest part of the job, drilling through that thing - THICK! center-punched then progressively sized drill bits up to about 1/2"; I was going to see if I could fit a grommet or seal with silicone but the fit is pretty tight; doesn't seem to need more) then another tube from there down to front right horizontal frame member.

I'll monitor and see whether it merits a catch-can or filter but for now it's done and ready for the road.

Pretty easy, even for this tighten-til-it-strips-then-back-off -1/8-turn kinda of guy....

Thanks for your help folks.  - BrianK

PS in case it helps anyone:  I have a couple tight bends in the tubing and initially it crimped, restricting flow.  I was able pretty easily to pinch it back to round shape and put on a couple of small cable ties to hold it in shape. 

[djl]

I just did the work.  2006 Softail Deuce with K&N 3909 air cleaner.

Ran 5/16" (ID) clear tubing from the breathers (secured with worm clamps) to a barbed Y fitting with one arm of the Y projecting through the backplate (toughest part of the job, drilling through that thing - THICK! center-punched then progressively sized drill bits up to about 1/2"; I was going to see if I could fit a grommet or seal with silicone but the fit is pretty tight; doesn't seem to need more) then another tube from there down to front right horizontal frame member.

I'll monitor and see whether it merits a catch-can or filter but for now it's done and ready for the road.

Pretty easy, even for this tighten-til-it-strips-then-back-off -1/8-turn kinda of guy....

Thanks for your help folks.  - BrianK

PS in case it helps anyone:  I have a couple tight bends in the tubing and initially it crimped, restricting flow.  I was able pretty easily to pinch it back to round shape and put on a couple of small cable ties to hold it in shape. 

 

[Coff 06]

I picked up a small braided line kit from O'Rielly Auto Parts.Had just enough to do the job when I did mine years ago.   
Coff 06

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[BrianK]

I just did the work.  2006 Softail Deuce with K&N 3909 air cleaner.

Ran 5/16" (ID) clear tubing from the breathers (secured with worm clamps) to a barbed Y fitting with one arm of the Y projecting through the backplate (toughest part of the job, drilling through that thing - THICK! center-punched then progressively sized drill bits up to about 1/2"; I was going to see if I could fit a grommet or seal with silicone but the fit is pretty tight; doesn't seem to need more) then another tube from there down to front right horizontal frame member.

I'll monitor and see whether it merits a catch-can or filter but for now it's done and ready for the road.

Pretty easy, even for this tighten-til-it-strips-then-back-off -1/8-turn kinda of guy....

Thanks for your help folks.  - BrianK

PS in case it helps anyone:  I have a couple tight bends in the tubing and initially it crimped, restricting flow.  I was able pretty easily to pinch it back to round shape and put on a couple of small cable ties to hold it in shape. 

I did think about taking pics along the way but decided not to for two reasons (i) others have already done, including some of the references folks provided to me in this very thread, and (ii) my iphone works on thumbprint, and once that thumb is anything but pristinely clean, I have to go wash and dry my hands to get it to work again - and this was a dirty job, what with oil/grease/road grime. 

[itsafatboy]

I ran them from heads to a KN filter that had 2 inlets , i also run ET krank vents i have not had any oil issues with dripping ,  but i also have a vent off my cam plate the RR cycle one that has a venting setup, 

[HogMike]

My EVO breather hoses take a long trip from the carb to the catch can on the left side, up and over to end at the rear fender.

My 2019 tubes go forward and under the bike to a filter just to keep whatever spray off the frame, etc.

Both seem to work well.

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[kink04fxd]

I would think that filter is going to eventually get soaked and drip. I run my breather hoses straight to the ground. No catch can. No filters.

[60Gunner]

Filters also get clogged. Learned this the hard way when I kept blowing rocker cover seals on a sporty build. No more filters here.  But I'm not  blowing a bunch of oil out in the first place. I run my oil level on the full mark too. None of this running the oil a half quart low band aid for poor crankcase breathing.

[Hossamania]

I'm a fan of running hoses without filter or catch can, mostly because I'm lazy and don't want to deal with them. My bikes are far from pristine, they get hell ridden out of them, a little schmutz on the bottom of the bike from some oil and water vapor is not a big deal to me.

[HogMike]

Filters also get clogged. Learned this the hard way when I kept blowing rocker cover seals on a sporty build. No more filters here.  But I'm not  blowing a bunch of oil out in the first place. I run my oil level on the full mark too. None of this running the oil a half quart low band aid for poor crankcase breathing.

I've been running this setup on my 124 M8 for the last 50k miles and never had a spot of oil under the bike. I do clean the filter every 5000 miles when I do the oil change. This bike is my touring rig and sees high speeds, low speeds, mountains, deserts and everything in between. It is a very nice motor!

My EVO vent system is a little different, a little more plumbing involved.
I empty the catch can every few rides. I'll get a tablespoon of fluid out. No filter on the end, not needed for this system.

[60Gunner]

Here's the thing that most don't think about. I didn't either when I did it. By eliminating the stock breather valves and running reed valves externally, the distance in between is now added to the crankcase volume BEFORE the breather valves. This alone would lower crankcase pressure I would think along with reed valves closing quicker than butterfly valves and not sucking a little air in first. Not to mention much easier to maintain should the need arise.
Just pop them off the hoses, remove two screws and open them up. The reed valve inside can be cleaned or replaced.
Lower crankcase pressure = better ring seal and less blowby.

Why are so many m8 builds adding dipstick breathers?

[60Gunner]

I ran them from heads to a KN filter that had 2 inlets , i also run ET krank vents i have not had any oil issues with dripping ,  but i also have a vent off my cam plate the RR cycle one that has a venting setup, 

I almost switched to gear drive just for this breather in the cam plate/cover. Did you try running this without the head breathers?
This is where the breather should be...in the crankcase.

[itsafatboy]

No i always have had the ET krank vent valves on heads (i also use 1/2" banjo bolts not sure that matters) , i also have the S&S rocker covers so there really isnt a one way in the vlave covers themselves,  i never get oil in the filter under the air cleaner the only oil i get is a little bit in the catch can from R&R camplate setup, 

one time i tried putting a one way valve on the cam chest breather hose but not a good idea it just pulled oil out all over the place so i had the two head one ways and one on the cam plate didnt work at all, i think thats why those S&S breathers(read valves) on the crank dont always help they cause sumpping

 

[itsafatboy]

So is there such a thing as to much venting , so if i vent from heads , and from cam plate , and say i have a oil cap vent for a softail would that cause issue i know over kill, but i do have a top fill oil tank and have a venting filler cap that i was going to put on just because i have it,  do we need any pressure in the tank to help push oil or am i way wrong .

[Hilly13]

Late to the discussion but thought I'd chuck this in as it may help someone, when i initially did the vent to atmosphere on my slim S 110 i drilled out the rocker support holes as per the common method, i ran 3/16 ID fittings, hoses etc, was fine at stock compression, even with cam changes, then i upped the compression to 10 to 1, tuning runs at sustained 6k plus RPM and the oil bag ejected the dipstick, more than once.
I figured i must of done a bad job of the hone but then i read something somewhere, changed all the fittings and hoses to 5/16 ID, drilled out the breather bolts as much as i dared, problem went away, true story.

[itsafatboy]

So i had the parts so i made a filler cap vent , mine is different its a topfil tank on my 01 fatbboy wanted the winged tank, but had a trans dipstick that i took the poll out of so there was hole it was a stick with a temp gauge that broke so perfect to use then added filter i had in a box of crap, so we will see if it works and doesn't spit crap out, i did take apart a tampon and put the soaky stuff around the area to catch if it does, 

 

[itsafatboy]

so now i have a venteded dipstick , and vented cam plate and vented one way valves on heads , i think im over vented and bored