Crank Case Venting on '01 Road Glide
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Road Warrior
Joined: Apr 2008
Posts: 1,266
Likes: 7
From: Indianapolis
Crank Case Venting on '01 Road Glide
I need some advice on a friends bike. He has a 2001 RG with 70K miles on it. At some point, the previous owner bumped this thing up to 117 ci. The bike runs good from stop light to stop light, but at a sustained speed of 75 mph and over on freeway cruising this thing blows out a bunch of oil through the breathers. (several pints). We've opened up the drains in the rocker carrier plates, but this hasn't helped things much.
Basically, he seems to be moving a lot of oil into the rocker boxes instead of just mist and the top end can't drain fast enough to evacuate all the oil. We're thinking that the crankcase is being over pressurized by the huge pistons in this thing and suspect we may have to vent the crankcase by some means other than the pushrod tubes. We've tried running a lower oil level as suggested by others, but it doesn't help things.
Has anyone else come across this with one of these big builds and if so can anyone suggest a good way to vent the crankcase?
The outfit that did the original upgrade has long since gone out of business so I can't turn to them.
Any advice is greatly appreciated.
Basically, he seems to be moving a lot of oil into the rocker boxes instead of just mist and the top end can't drain fast enough to evacuate all the oil. We're thinking that the crankcase is being over pressurized by the huge pistons in this thing and suspect we may have to vent the crankcase by some means other than the pushrod tubes. We've tried running a lower oil level as suggested by others, but it doesn't help things.
Has anyone else come across this with one of these big builds and if so can anyone suggest a good way to vent the crankcase?
The outfit that did the original upgrade has long since gone out of business so I can't turn to them.
Any advice is greatly appreciated.
Road Master
Joined: Nov 2007
Posts: 771
Likes: 3
From: St. Bonifacius, MN
This or make one like this.
http://feulingparts.com/wp/feuling/v...breather-kits/
Considered going this route to stop my dip stick blow out issue. I have the mistfree setup in my heads as well as the hi volume oil pump . It helps, but did not stop all the oil mist. I can live with the small amount of oil that does get by, but can not live with losing my dip stick and all the oil that blows out covering my right side (and my wife when she was on it). I went with the Baker screw on oil dip stick setup.
http://feulingparts.com/wp/feuling/v...breather-kits/
Considered going this route to stop my dip stick blow out issue. I have the mistfree setup in my heads as well as the hi volume oil pump . It helps, but did not stop all the oil mist. I can live with the small amount of oil that does get by, but can not live with losing my dip stick and all the oil that blows out covering my right side (and my wife when she was on it). I went with the Baker screw on oil dip stick setup.
Banned
Joined: Jul 2009
Posts: 3,719
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That oil tank breather kit might seem to help lessen the amount of oil being blown out, but the problem remains. Too much pressure in the crankcase/valve train. You are surely going to have higher compression with the Cubic Inches yer runnin, but if it's blowing by the pistons/rings, I'd have to open it up and take a good look at the wear.
Check ring gap positioning also. Seen many first timers (and a few pros even) get the ring gaps positioned in a manner which allowed too much blow by. If you aren't sure of the mileage since the build, then the rings and/or pistons, valve guide/stem clearance, may have excessive wear. Treating symptoms is a work around, not a solution. Ya gotta address the issue directly, if you want to resolve the problem...
Check ring gap positioning also. Seen many first timers (and a few pros even) get the ring gaps positioned in a manner which allowed too much blow by. If you aren't sure of the mileage since the build, then the rings and/or pistons, valve guide/stem clearance, may have excessive wear. Treating symptoms is a work around, not a solution. Ya gotta address the issue directly, if you want to resolve the problem...
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Road Warrior
Joined: Apr 2008
Posts: 1,266
Likes: 7
From: Indianapolis
That oil tank breather kit might seem to help lessen the amount of oil being blown out, but the problem remains. Too much pressure in the crankcase/valve train. You are surely going to have higher compression with the Cubic Inches yer runnin, but if it's blowing by the pistons/rings, I'd have to open it up and take a good look at the wear.
Check ring gap positioning also. Seen many first timers (and a few pros even) get the ring gaps positioned in a manner which allowed too much blow by. If you aren't sure of the mileage since the build, then the rings and/or pistons, valve guide/stem clearance, may have excessive wear. Treating symptoms is a work around, not a solution. Ya gotta address the issue directly, if you want to resolve the problem...
Check ring gap positioning also. Seen many first timers (and a few pros even) get the ring gaps positioned in a manner which allowed too much blow by. If you aren't sure of the mileage since the build, then the rings and/or pistons, valve guide/stem clearance, may have excessive wear. Treating symptoms is a work around, not a solution. Ya gotta address the issue directly, if you want to resolve the problem...
Ultimately, we have come to the conclusion that instead of the engine breathing air with a little oil mist, it is breathing oil with a little air in it, hence the step of alleviating crank case pressure. If anyone can think of another reason this thing is breathing oil, I'd love to hear it.
Banned
Joined: Jul 2009
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You may already know also, that new rings will allow more blowby until they are broken in and seat properly. Nothin you can do about that, except give it time to seat. And you seem to be knowledgable enough to realize the additional cubes adds to the forces pushing the oil around in the crank case. That's just another thing you have to deal with not being able to get around.
The breathing mechanism on these twin cam motors has never been adequate either. There are some aftermarket kits that replace the OEM rocker box filter/valve and say they eliminate most if not all oil spray. Can't recall any particular brand atm. I'll have to try searchin a bit and if I find what I'm speaking of, I'll post back.
The breathing mechanism on these twin cam motors has never been adequate either. There are some aftermarket kits that replace the OEM rocker box filter/valve and say they eliminate most if not all oil spray. Can't recall any particular brand atm. I'll have to try searchin a bit and if I find what I'm speaking of, I'll post back.
Advanced
Joined: Apr 2008
Posts: 87
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Could the scavenge side of the oil pump be weak. Did this just start or has this been going on for a while.
On my bike the oil pump seal was pinched and was sucking air in stead of oil.
Its just something to check.
Martin
On my bike the oil pump seal was pinched and was sucking air in stead of oil.
Its just something to check.
Martin
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Banned
Joined: Jul 2009
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Here ya go nemick, this is the replacement vent system I was talking about...
Write up for installation of Doherty Mystfree vent system:
http://www.bikerrogue.com/Articles/T...m_Breather.htm
Doherty Mystfree:
http://www.dohertymachine.com/index.php?cPath=1
Write up for installation of Doherty Mystfree vent system:
http://www.bikerrogue.com/Articles/T...m_Breather.htm
Doherty Mystfree:
http://www.dohertymachine.com/index.php?cPath=1
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Road Master
Joined: Nov 2007
Posts: 771
Likes: 3
From: St. Bonifacius, MN
The Doherty Mystfree vent system is the one I am running. It helps, but does not stop all the oil mist. If you are running the stock oil pump then the S&S crankcase breather valve that goes behind the oil pump may work better. I am using the Feuling Super pump and the S&S valve doesn't work togther.
I agree with retyddone As it sounds like an oil pump scavenge issue with that amount of oil kicking out.
I agree with retyddone As it sounds like an oil pump scavenge issue with that amount of oil kicking out.
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