I was wondering if anybody has ever replaced the oil breather system in the air cleaner? The reason I ask is it dumps a little oil into the intake . I bought some air intake cleaner and used a soft bristled toothbrush too clean up the oil residue. I wonder if a guy could reroute the breather tubes ?
Engine oil breather
- Thread starter 52chevy
- Start date
- Here Ya go.
I have up-graded the Air Cleaner on my '12 Ultra Classic to the SE high-flow one (see pix below). This kit includes the mounting bolts shown in the first set of photos below that are hollow with a port in the side that vents the crankcase to the air cleaner and engine cylinder intake through ports in the back plate. This allows the oily mist from the crankcase to be sucked into the cylinders and "burned". But I do not like this for a couple of reasons:- The oily crankcase vapor accumulates in the air filter area and eventually drips out of the A/C cover onto the engine making a mess
- Burning the oily mist in the engine contributes to carbon buildup and fouling of the IAC over time
Cheers,
TQ
Last edited: Sep 12, 2017
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Jeff Klarich, Jul 9, 2021Report
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Jeff KlarichExperienced MemberContributor
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Go to Youtube and put in Harley-Davidson "air intake breather bypass", some good videos on how to do it as well.
It's an easy DIY job and your scoot will thank you for it.
It's an easy DIY job and your scoot will thank you for it.
ThunderRogue
Active Member
I see you're fairly new to the forum so I can assume you're new to Harley's too. Therefore I won't give you too much guff about your question. But if I was to, I say "where the heck have you been?" LOL! Can't see if you posted what year and model your bike is but yeah that's a very common practice to route those breather tubes to atmosphere. Google and YouTube are your friends. It can be done by yourself for under $20 depending on what you have and your skill set. Lots of people willing to share knowledge here.
dolt
Well-Known Member
At least the OP recognizes that the oily mist containing unburnt fuel, water and oil mist being sucked back into the intake is not a good idea. As TRogue points out some 3/8 fuel hose, hose clamps, and a filter or small catch can for $20 or less and an hour or so and problem solved. There are many ways but the two most common variations are final venting to the atmosphere which requires a bit more hose of venting into a small filter or mesh filled but vented catch can. The come in all shapes and sizes. Three photos attached; the first is my DIY solution using two crank vents (think one way EGR valve) that won't allow the passage of any vented mist back into the system. The second is my brothers DIY fix using a small vented cannister filled with the same mesh used in the head breathers. The third is a photo I picked up somewhere. Assuming ring seal is good, maybe have to replace the filter or the mesh a couple of times a year. Some go to greater lengths to make the system look more high tech with braided lines and colored ANA fitings but I don't have any pictures of those.
Attachments
ThunderRogue
Active Member
Mine was 1/4" and already had a 90⁰ turn on the breather bolts so I just angled them down and installed a tee behind the Air Cleaner. Where the rubber hoses went into the backing plate I tapped them 3/8-16 and installed short set screws with locktite. To ensure they'd never come out I punched the threads on the back side and turned them in tight. The end hose then got routed down and between the front cylinder and intake pushrod tube and then down beside the clutch cable and oil pressure sender. Open to atmosphere just below the frame. A good running motor will hardly produce any oil mist and getting the hot air out of the intake is a win win. Any of the screen type filters have the chance of filling with oil mist and then collecting dirt therefore plugging them. I see no reason to install any catch can or vent. It just creates more of a maintenance issue.
dolt
Well-Known Member
Not a maintenance issue. Have run filters but changed to a small vented "catch can" from Trask. It is filled with the mesh used in the OEM head breathers. Many miles and nary a drop out of either; I change the mist once a season. Of course, I built the motors and ring seal is spot on. Not an environmentalist but like the idea of being able to see quantity and quality of oil mist is being vented out. If it inreases suddenly, time to find out why. Some say "tomato", some say "tomaaahhhto".
ThunderRogue
Active Member
Hah, I agree. And you have a clean running motor. My point. As for knowing if the "mist" increases, my garage floor will tell me. I'm just one of those guys that believes an open vent should actually be "open". Can we still be friends? LOL!Not a maintenance issue. Have run filters but changed to a small vented "catch can" from Trask. It is filled with the mesh used in the OEM head breathers. Many miles and nary a drop out of either; I change the mist once a season. Of course, I built the motors and ring seal is spot on. Not an environmentalist but like the idea of being able to see quantity and quality of oil mist is being vented out. If it inreases suddenly, time to find out why. Some say "tomato", some say "tomaaahhhto".
dolt
Well-Known Member
Absolutely we can. However, I will have to overlook your use of 1/4" hose in lieu of 3/8" which is the preferred DIY Standard but I won't let that stand in the way of friendship.
ThunderRogue
Active Member
So should I have used a 1/4" x 3/8" x 3/8" tee? The barbed breather bolts coming out of the heads on my '04 are 1/4". I used the KISS method.Absolutely we can. However, I will have to overlook your use of 1/4" hose in lieu of 3/8" which is the preferred DIY Standard but I won't let that stand in the way of friendship.