Harley Davidson Air Intake Breather Bypass

This video deals with getting rid of what some call the "Harley Slobber." Th ugly little oil drip that comes out of the intake of a Harley Davidson. Mine has an Arlen Ness Big Sucker Air intake system and I hate oil dripping onto the motor or getting on my pants when it is not necessary. There is a way to bypass this problem and it involves a little time, a couple basic tools and knowledge. I once read about how to do this and felt I needed to do a video of what it takes to do this modification. I am putting a small parts list in the description of some parts you should order or get to do this project.
Parts:
3/8" stainless barbs with 1/8" NPT threads (Qty. 2)
1/8 NPT Tap and a corresponding drill bit (11/32)
3/8 oil resistant hose
6mm set screws (hex head) with a 5.2 mm drill bit
Red and Blue Loctite (Red is for the set screws)
Tools:
Basic hand tools
Drill press is the best thing to use, if you have one. I do not, so a plain drill and clamps.
I hope you get to enjoy doing this and reap the benefits.

[@irishguyjg_2ndchancerecovery]

Thanks brother Scotty. I'm on a sportster iron 1200 and alot of the issues you guys are having on some of the big bikes, I'm obviously having same/similar, so I appreciate vids like this. God bless you

[@jefffrayer8238]

Good idea for sure. Cars, tractors of the 50's, 60's vented crankcase just as you now have. Easy to know your motor was tired by how much blowby comes out the breather tube, Lol. If you don't want a drip on the floor you could drill a hole in prescription bottle cap with a tight fit for the hose and small vent hole. Easy to hide it down low. You did a great job but I would use J.B. weld instead of set screws. Much easier, won't come loose but if it did much safer going through the motor than set screws.

[@scottygarage7408]

I like the idea of JB weld or even RTV for plugging the holes. I used and have checked the set screws that I put in to make sure they are working fine. I had used some loctite to hold and it has held them well. I had a 1950 MG that when it would starting getting hot it would actually smoke from the vented oil cap. That car hated traffic. I am still using the little filte on the end and have not had an oil drip yet, so I am going to leave it alone.

[@jefffrayer8238]

@@scottygarage7408 I got thinking that a small filter would probably work great. Glad no oil drips. I'm sure the set screws will stay put just fine.

[@fredmore8788]

I went to my local auto parts and spent $8.00 and exactly what you did...Thanks for the video.

[@scottygarage7408]

That is great, glad it helped and worked out for you.

[@daveking4246]

Where is it going after it goes between the cylinders...is there a part 2 showing what you did with it after routing between?

[@johnliotta2583]

Mc gee, from senior management came down to see the build before complete. Haha love it.

[@scottygarage7408]

Yeah, him and Abby tend to do that.

[@irishguyjg_2ndchancerecovery]

Don't lose those little quarter size round gaskets. I had one pop out of my stage 1 BIG sucker and I had issues until minor issues until I realized what had happened.

[@FreeSwimmer]

I agree thats good work, but I got lazy.. I was doing a Big Sucker aircleaner on 1200 Sporty and needed a backing plate. DK Customs has everything needed for the EBS System with support brackets and backingplates and breather kits with filter. So, I usually DIY many things, but their kits are top shelf and I needed the other parts anyway.

[@misterrickbuddy9072]

Agree with you on the backing plate however I'm a power pack is that basically the same thing as a stage 1 kit cuz it seems like it's identical to that pretty much

[@gurnblanstein9816]

A problem with your routing. Were the two short hoses come to the tee the hose that connects to that tee actually runs up him to go between the cylinders. That incline in the hose will cause it to act like a catch can. It will fill up with oil. Shorten the two small hoses so the hose from the t can run downhill or level across between the cylinders.

[@johnschoonmaker-tm3ll]

Terrific information, thanks for posting!!!

[@perryhart3172]

The throttle body can be cleaned, its the top of the pistons that suffer

[@scottygarage7408]

I agree, that is why I am hoping that over time the carbon will flake off since no new used oil is coming in plus using some cleaners in my tank to reduce and clean the carbon deposits.

[@danielpalmer1876]

@@scottygarage7408 Marvel mystery oil works great for carbon deposits.

[@Jake-cz1kb]

Why would you use such a huge fitting and hose? Look at the size of the breather passage through the air cleaner at time stamp 5:05.

[@-MrRichBiker1967]

Hey Scotty thanks for the video very informative, but I just took 2 3/8 hoses from the top breather bolts, and let it drain under the bike instead of going through all that, no? Okay I could dress it up a little bit not the neatest thing but it works. In your case you have to worry about more leaks now. And I hate chasing down air leaks

[@webtoedman]

I have a chain conversion on my 2004 Sporty. I think routing the breather pipe to drip on the chain would work.

[@TyScott85]

Some dual sport bikes do that from the factory. I would.

[@scotty2221]

I need an external breather, I have a lot of carbon build up but, I don't want to drill holes. I have a Stage 1 K&N filter and assembly already but, DK says I still have to drill holes? Please help.

[@bluebullock3143]

Fill mine with gasket sealer works perfect

[@cobraninetysix3883]

I had a Scotty when I was a kid..., now I have to go shopping for another!

[@scottygarage7408]

Yeah, they are fun.

[@shawn92882]

Oil on the filter is the least of the downsides

[@firebearva]

Pull the rocker covers and replace the breather baffles.

[@bettytownsend3459]

I like there apps nice work

[@scottygarage7408]

@@wingandhog I have already replaced them when I had a small leak in the valve cover and did the Rocker Locker kit.

[@TacticalTorc]

I like the idea of venting it through the gap between heads, but since the hose is low and rises to go between, if you have excessive blow-by oil sitting in the line, won’t that disrupt the breather from getting airflow?

[@scottygarage7408]

I actually ran it between the cylinders and when I came out the other side I ran it down to the top of the primary and ran it toward the front originally. I have since re done it to the back and have no high spots for oil to collect. I caught that later on as well. good catch.

[@shanemilhornmilhorn5074]

People should know, when you start drilling and tapping, you'd better know what size hole for the thread size your cutting. When that tap breaks in the hole, your screwed. You'll have to go purchase a new system.

[@mgkent2010]

Go up it works great an no oil gets away just crankcase pressure

[@apache437]

Unless you’re running vacuum to the catch can, gravity will pool the oil in the low spots of the hose. Great idea to bypass though.

[@none4085]

How about an update on the Catch Can? Finished product and how & where you mounted it? Any information would be greatly appreciated! Thanks...

[@scottygarage7408]

I wish I could add an update. My bike was stolen and wrecked in a police chase. It was doing great until then though. I do have a new bike an 06 ultra, that I am hoping to start making videos with soon.

[@none4085]

@scottygarage7408 OH man, bummer about your scooter! Sorry to hear that, hope you're new ride treats you right. Appreciate the response...great install video btw! Thanks

[@motorcitymadman146]

So what did you do with the holes in the back of the intake? I would guess that is not good to leave them open as it will suck air through it.

[@flyinbrianewing]

At 5:40 he discussed this.

[@lh1678]

Love the Scottys!..Love Scotland!

[@scottygarage7408]

He is a blast to have running around.

[@joerectifier]

Excellent video - thanks

[@westieBrucedavidson]

Did you find idling got different and any changes mate? Thinking of doing same thing but tap some brass elbows into it Great work by the way😊

[@scottygarage7408]

I did not notice any change. I did notice less oil in the intake.

[@Heavy69Metal]

How about ole school and vent it to the ground? Also what’s about vacuum in it?

[@friendlyneighborhoodbikeme8535]

Or you could just change your umbrella valves in the rocker plate, they are what allow oil into the breather when they become old and hard. Bad idea to do this, there's nothing wrong with the crank breather system if everything is in working order.

[@randymccalla9995]

Yes sir change out the breather valves in the rocker plate, new filters and gaskets, makes the original system work..When you are getting a lot of oil in your air cleaner the valves have hardened and the filters are saturated always put new gaskets.

[@jerrycagle7565]

Great video, my question is doesn't the bike lose its vacuum, it needs that vacuum or am I missing something, let me know.

[@scottygarage7408]

It does not lose the vacuum. It gets vacuum out of the manifold which is behind the air intake.

[@n2daair23]

Well, I just purchased a Big sucker from J&P and was told with that A/C setup that I didn’t need an external breather? Now I’m confused again, lol!

[@edwarddominguez747]

n2 daair there lying to you. i have a big sucker as well and oil still pukes out of the tiney holes on the inside of the air cleaner. installing mine next week.

[@kimehrlich1002]

I have been running the same setup on my deluxe for almost ten years in which seven of those years where for a daily driver! I maintain my scooter regularly with out fail and never ever have had those issues unless I over filled my oil bag which you only do once! The whole point behind running the Arlen ness big sucker besides mass air flow is getting rid of all the rubber and plastic bullshit, but if you want to fuck your bike up it’s your right!!!!!!!!!!!!

[@scottygarage7408]

Yeah, I run low oil in the bag to avoid the Harley Slobber and learned that early on. The motor still produces gasses no matter how tight and well maintained it is. I am like you and maintain my bike rather well. I have not had to clean my throttle body since I did this and no ill effects to the bike, so all good. What year is your scoot?

[@n2daair23]

The Arlen Ness big sucker I just got requires no breathers. Is this an older setup?

[@scottygarage7408]

@@n2daair23 my bike is an 06 and my wife has an 08. Hers has a different set up and they both recirculate the crank case gasses into the intake. I did this to stop the recirculating of the games which gets carbon and oil on the intake.

[@thomasfrawley5798]

I installed this on my softail and I seem to be getting water in the catch can,I guess it's condensation but nobody has said anything about that happening.

[@scottygarage7408]

That could be condensation, but the question is how much and how often?

[@jamesbennett9654]

If your getting that much oil in your breather/ air filter, perhaps you should go through your motor anyway?

[@bobberguy1]

All twin cams and M8s puke that much oil. Take the spark plugs out and look at top of pistons after 10,000 miles.

[@marlboro1632]

that hammer is for laying tracks for the railroad

[@TheJMan1K]

What’s a decent tool kit to work on Harleys? Picking up my first Dyna this weekend. I have a Pittsburgh steel 232 piece set and a torque wrench. I’m guess all I need after is a motorcycle lift?

[@scottygarage7408]

I have been building my tool kit for about 30 years and I still do not have everything. I would make sure to have a torx set and hex key set. I would also get a factory manual for your dyna and you will see specialty tools and other tools they use for the dyna to help with future tool needs.

[@bonez6349]

Man i cannot find a self-tapping hex key set screw nowhere.! lol where did you get this.? Do you have a link...?

[@scottygarage7408]

I did not use a self tapping hex. I used a tap and threaded the drill hole and used a regular hex.

[@randymccalla9995]

I would be worried that the little screws would get sucked into the engine and crack a valve seat .

[@scottygarage7408]

That is why used loctite and RTV in the hole.

[@jonsixxx6569]

Would super glue work better and less risk then using set screws? Fill the hole with super glue

[@scottygarage7408]

I was thinking RTV as it is oil resistant. I used thread lock on the set screws and recently checked them and they have not budged.

[@chipper442]

You got a follow for the content but mostly the Sctties lol.

[@scottygarage7408]

I want to start doing content again soon and McGee is arroooing to work on a bike

[@softailslim7146]

What size tap did you use ?

[@edgeiger1514]

It's been 2 years since this video, did anybody tell him that they make an automatic center punch that can be had for about $10? Sure would have made that a lot cleaner!

[@scottygarage7408]

I agree that would have made it cleaner and since that video I was broken into and had many of my tools stolen, but I actually added ones of those into the collection and I recommend using them for a cleaner job. We learn as we go, never stop learning.

[@gaknskk]

Hopefully that rtv or set screw dont end up on your engine

[@scottygarage7408]

The RTV would not really do any damage, but I used locktite as a back up and when I clean the air filter I check just to be safe and it has not budged.

[@mikebrown1741]

If properly tapped and seated with the addition of red loctite those screws aren't ever going anywhere. I did this to my 96 evo 70k miles ago. It would be hard to get those out ever even if you wanted to.

[@gaknskk]

@@mikebrown1741 That's exactly how I did mine on my 16 sgs screaming eagle air breather with no issues

[@danielgallant1562]

You got that right

[@Jimarceo]

Can you please explain to me why does Harley do this why have a problem on a brand new bike why Japanese or Ducati or triumph doesn’t have this problem

[@scottygarage7408]

All vehicles now a days have these systems. In the past they vented into the environment, but it was determined to be bad. How they are piped is what makes the big difference. Some are after the throttle body and others before. I also want to add my Bike is from 2006 with over 70k miles. ETA: I went on a Ducatti forum and they have the same issue according to some threads.

[@zonktified1247]

Basically...EPA mandates

[@josermalavejr466]

Wish I knew what year that harley is.

[@scottygarage7408]

Mine is a 2006 with an 88cu in motor.

[@mustangguns7230]

Nice

[@iblacka1]

Make sure them screws don't come out and get sucked into the engine.

[@scottygarage7408]

Oh yeah, I check them to make sure they won't. Good news is the locktite is holding and they have not budged since I did it.

[@DylanMastin-fy2uo]

​@@scottygarage7408 what screws did you use?

[@stevesyncox9893]

Not “combustion gasses, crank case gasses.

[@scottygarage7408]

Good catch, yes crank case gases.

[@markorr1874]

where is filter available

[@scottygarage7408]

I bought mine at Advanced, but you can find them in other parts stores.

[@rocketman3776]

Wish you would have showed the Oil Catch Can. Often you will see people short come their videos

[@scottygarage7408]

I still have not done the catch can. I cannot find one I like for the bike. They are either too big or too small.

[@charliedee9276]

@@scottygarage7408 You don't really need a catch can. I did this on my 98 evo a few years ago, instead of a catch can I ran the second hose into a tee. The upper leg runs to a little filter and the lower leg goes down to the bottom of the bike where it is plugged. I drain the lower leg at every oil change and get about a tablespoon of oil. Has never leaked or filled up with more than a very small amount of oil, has worked like a charm even during extended high speed highway runs.

[@scottygarage7408]

@@charliedee9276 I have kind of fallen to that same idea and am not bothering with a catch can, since not enough oil is getting "sucked" out since it is not being vacuumed out by the intake.

[@scottgorman7166]

@@scottygarage7408 look at those small polished aluminum tool tubes they have for Harleys

[@Jims07yfz450]

Looks good but for a 20k motorcycle this shouldn’t be needed

[@scottygarage7408]

I have done this to cars as well, because they do the same thing. The government mandated the PCV to push any gasses left in the crankcase back into the motor to reburn. I did it to keep my throttle body clean, just like on cars, but it is easier on a car.