A/C Breather Venting
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Road Warrior
Joined: Apr 2007
Posts: 1,354
Likes: 1
From: S.W. Florida
A/C Breather Venting
I know that this is a common problem, but need some direction as to the best way to address it. Put about 40 miles on my bike on Saturday after resealing the transmission and replacing the transmission pulley. Mostly in city driving and never over 55-60mph. Checked for leaks after the bike cooled off. The transmission was dry, but I locatedsome oil mist on the rear rocker box and running down the rear exhaust heat shield. To be fair I have noticed this before and just cleaned off the oil.
During the past six months I have done the following:
1) Repaired an oil leak at the cam cover due towarpage. I installed a new HD cam cover, Torrington cam bearing, Andrews EV-27 cam, SE lifter blocks/lifters, SE adjustable pushrods and replaced the factory plastic breather with an S&S reed valve breather.
2) Repaired the previously mentioned oil leak on the left side of the tranny. Acorroded and pitted spacer had torn up the mainshaft seal.
Thecarb is an S&S Super E with the head breathers vented to the A/C.I removed the A/C cover on Sunday and wiped about a tablespoonful of oil out from inside of the A/C assembly. The K&N element was not saturated with oil. This spring the cylinders will be bored .005, SE heads will be installed and of course the top end gaskets and umbrella valves will be replaced.
Last oil change about 500 miles ago was done by an Indy withRedline 20-50 and aDrag Specialties filter. I plan to install a K&N oil filter that I have and double check the oil level to make sure that it is on the low side.
Any ideas on how to further minimize the problem?Any ideas or advice would be appreciated.
During the past six months I have done the following:
1) Repaired an oil leak at the cam cover due towarpage. I installed a new HD cam cover, Torrington cam bearing, Andrews EV-27 cam, SE lifter blocks/lifters, SE adjustable pushrods and replaced the factory plastic breather with an S&S reed valve breather.
2) Repaired the previously mentioned oil leak on the left side of the tranny. Acorroded and pitted spacer had torn up the mainshaft seal.
Thecarb is an S&S Super E with the head breathers vented to the A/C.I removed the A/C cover on Sunday and wiped about a tablespoonful of oil out from inside of the A/C assembly. The K&N element was not saturated with oil. This spring the cylinders will be bored .005, SE heads will be installed and of course the top end gaskets and umbrella valves will be replaced.
Last oil change about 500 miles ago was done by an Indy withRedline 20-50 and aDrag Specialties filter. I plan to install a K&N oil filter that I have and double check the oil level to make sure that it is on the low side.
Any ideas on how to further minimize the problem?Any ideas or advice would be appreciated.
Road Master
Joined: Jun 2005
Posts: 916
Likes: 1
From:
RE: A/C Breather Venting
run the breather tube down below the bike somewhere and attach a filter...this lest it breath and any oil collects in the filter.I use a cheaph,about 8.oo ,9.00 form an auto store.Works well and no mess.
Thread Starter
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Road Warrior
Joined: Apr 2007
Posts: 1,354
Likes: 1
From: S.W. Florida
RE: A/C Breather Venting
dert,
I can and have thought aboutthat. What do I need to do plug the opening in the S&S backplate and run an adaptor with a line off the S&S hose, or is there a better way?
I can and have thought aboutthat. What do I need to do plug the opening in the S&S backplate and run an adaptor with a line off the S&S hose, or is there a better way?
Stellar HDF Member
Joined: Feb 2007
Posts: 2,558
Likes: 280
From: Russellville, Arkansas
RE: A/C Breather Venting
I run a T-fitting on the back of the air cleaner backing plate. The gases keep going, while the excess oil drops into a lower hose attached to the T-fitting. I have a short bolt into the hose that keeps in the oil in there. I change the oil and I drain the oil from that hose. Usually, there is only about a table spoon of oil in there. I believe Harley should adapt this idea to new bikes or at least Screaming Eagle should make a kit for it.
It is better than having it vented to the atmosphere. It is not messy and no oil makes it to the air cleaner housing either.
There is a link to the idea on the web somewhere.
It is better than having it vented to the atmosphere. It is not messy and no oil makes it to the air cleaner housing either.
There is a link to the idea on the web somewhere.
Stellar HDF Member
Joined: May 2005
Posts: 2,137
Likes: 17
From:
RE: A/C Breather Venting
Re-routing the breather tube doesn't solve the problem. Is your bike wet-sumping? Possibly the check valve in the oil pump isn't seating and is letting oil drain into the crankcase?
Cruiser
Joined: May 2007
Posts: 193
Likes: 0
From:
RE: A/C Breather Venting
I vented mine to a small Honda oil filter, and a black plastic filter wrench. Reamed the inside of the filter wrench so that the filter would pop inside the wrench. Drove the wrench fitting out of the middle of the filter wrench, made a bracket to mount it to the down tube. No more messy blow by on the bike, or the riders behind me or my air cleaner.
[IMG]local://upfiles/31141/3AF0B888429C4E04874192A0CD054A88.jpg[/IMG]
[IMG]local://upfiles/31141/3AF0B888429C4E04874192A0CD054A88.jpg[/IMG]
Road Captain
Joined: Apr 2005
Posts: 535
Likes: 14
From: Highspire Pa
RE: A/C Breather Venting
First I tried the krankvent on our 1990 FLHTCU, it helped but still needed to run a hose to the ground, on Saturday I took that off and installed an Oil Mist Collector - about 200 miles so far and no oil, keeping my fingers crossed . It's ironic, I did not have the oil/breather problem until after I had some performance work done to the engine.
http://www.motorcycles-stuff.com/pag...MistColl.shtml
the krankvent ( did not stop oil, may have helped some )
http://www.et-performance.com/kv.html#Pre93%20EVO
http://www.motorcycles-stuff.com/pag...MistColl.shtml
the krankvent ( did not stop oil, may have helped some )
http://www.et-performance.com/kv.html#Pre93%20EVO
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Road Warrior
Joined: Apr 2007
Posts: 1,354
Likes: 1
From: S.W. Florida
RE: A/C Breather Venting
Thanks for the tips guys.
MP, the engine is not wet sumping. This is not a large amount of oil, just enough to be a PITA.
Jake, good idea except the S&S backing plate is bolted through the banjo bolts. The S&S breather hose is a molded one piece affair with three female ends, one to each banjo boltand one to the rear of the backing plate. This all runsover the top of the carb andI can make something up with a T fitting, but it's backyard engineering and not going to look very good. Did not know if maybe there was a solution out there that would work with the S&S setup like I've seen for other carb setups.
MP, the engine is not wet sumping. This is not a large amount of oil, just enough to be a PITA.
Jake, good idea except the S&S backing plate is bolted through the banjo bolts. The S&S breather hose is a molded one piece affair with three female ends, one to each banjo boltand one to the rear of the backing plate. This all runsover the top of the carb andI can make something up with a T fitting, but it's backyard engineering and not going to look very good. Did not know if maybe there was a solution out there that would work with the S&S setup like I've seen for other carb setups.
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Cruiser
Joined: Sep 2005
Posts: 130
Likes: 2
From: NH
RE: A/C Breather Venting
I had misting problems for years. Did the SE a/c thin and had oil misting in there regularly. Added a plumbing mod like one mentioned in earlier posts. That helped but still got oil spew on pipes after highway riding. Finally installed a crankcase breather that vents to a hose under the bike's frame AND use 3/8" hose run down from backing plate on carb that also connects to it down below. It's almost invisible and I don't have any more misting problems even running 10:1 pistons and SE heads.
Thread Starter
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Road Warrior
Joined: Apr 2007
Posts: 1,354
Likes: 1
From: S.W. Florida
RE: A/C Breather Venting
Spoke with a local Indy yesterday who is all too familiar with this and says it's even worse on Sportsters. FWIW, says that alot of the fixes sold out there really are a waste of money. He has a chrome double into single downline adaptor that he can adapt to use with the S&S backing plate. We are going to do that next week after returning from Daytona. I'll advise on how this mod works out.