A Catch Can On A Modern Harley Motor?
#21
10-4 on not reading anything and learning something new.
The following 2 users liked this post by crazytown:
07UltraGuy (02-09-2022),
perki48 (02-09-2022)
#22
I'm just thankful that we have a member who knows everything and doesn't need to read about what others are experiencing.
The following 4 users liked this post by 07UltraGuy:
#23
Was really enjoying reading this thread and learning a little something about the use of a catch can. Have an 03EG with a mild set of cams and punched out and completely understand that it's not a requirement for a stock twin cam, but I think any little bit you can do helps. Normally clean the IAC once or twice a year and things are good to go.
Enjoyed the pictures @07UltraGuy posted. Nice job with using a combination of AN fittings, the small breather filter, the catch can, and the custom bracket.
Saddened to see the thread take a bit of a down turn. Oh well...at least I learned something
Enjoyed the pictures @07UltraGuy posted. Nice job with using a combination of AN fittings, the small breather filter, the catch can, and the custom bracket.
Saddened to see the thread take a bit of a down turn. Oh well...at least I learned something
The following users liked this post:
07UltraGuy (02-09-2022)
#24
I externally breath all of my bikes.. Every engine is going to experience blow by. The air oil separators in the heads aren't perfect. Yeah, good ring seal blah blah blah but ring seal is also dependent on a fully warmed up engine. What happens until then and what happens when an engine is warming up? What happens when oil is warming up and starts to burn off the water? I have seen what is in larger catch cans and I don't want that going through my engine. Valves don't need extra lube. If they did. I would lube them with corn fuel over discharge from breathers.
On another note. I have never seen any reason to filter the air coming out of the engine either. With the one way check valves in the heads or inline with external breathers. There is no reason to filter air before it hits atmosphere. What I have seen happen. Oil makes dirt stick to filter and clogs them. Then you are venting this pressure out of seals. Usually the main single lip seal of the output shaft into the primary or base orings.
On another note. I have never seen any reason to filter the air coming out of the engine either. With the one way check valves in the heads or inline with external breathers. There is no reason to filter air before it hits atmosphere. What I have seen happen. Oil makes dirt stick to filter and clogs them. Then you are venting this pressure out of seals. Usually the main single lip seal of the output shaft into the primary or base orings.
Last edited by hrdtail78; 02-09-2022 at 03:19 PM.
The following 2 users liked this post by hrdtail78:
07UltraGuy (02-09-2022),
bigal51 (02-09-2022)
#25
...There is no reason to filter air before it hits atmosphere. What I have seen happen. Oil makes dirt stick to filter and clogs them. Then you are venting this pressure out of seals. Usually the main single lip seal of the output shaft into the primary or base orings.
1- I hated the constant oil drip line down the timing cover, and wanted to eliminate that, along with addressing the IAC issue.
2- I was a bit skeptical that the small holes in the lid of the catch can were sufficient to allow the pressure to dissipate without sending out a mist of oil, water, and mildly pressurized air onto the side cover, etc. essentially just moving the problem from inside the air cleaner/intake, to the side of the bike and my leg.
3- I punched a hole through the filter material, inserted a custom vented stem (to allow the exhausted air mixture to get to the bottom of the catch can before being restricted by the filter), then I added an 'upstream' filter element to simply reduce any back pressure that the catch can & fittings might have created.
All of this allows me to run the bike at full oil capacity without getting the mess of the oil blow by in the intake, or on the the timing cover. I could have accomplished this with a rubber hose and a clamp or two, but that would not have looked as good or kept me busy for as long.
#26
Harley owners are such fickle and OCD bunch..wanna' really know what's best for your bikes, and yourself? ride more, fuss and read about problems less
#27
In mjwebb's defense...as indifferent as his posts appear, I can guarantee that he read that thread long ago. It was posted in 2012. He stays pretty current on things. Harleys loading up with carbon due to a crappy crank ventilation system is a very old "issue". In truth it really doesn't matter all that much. Yes you can reduce carbon on the piston and keep gunk out of the IAC and throttle body. Modern bikes don't suffer much. FWIW, this was my answer to a catch can:
The following 2 users liked this post by strych9:
07UltraGuy (02-09-2022),
ictghost (08-30-2024)
#28
In mjwebb's defense...as indifferent as his posts appear, I can guarantee that he read that thread long ago. It was posted in 2012. He stays pretty current on things. Harleys loading up with carbon due to a crappy crank ventilation system is a very old "issue". In truth it really doesn't matter all that much. Yes you can reduce carbon on the piston and keep gunk out of the IAC and throttle body. Modern bikes don't suffer much. FWIW, this was my answer to a catch can:
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