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    Default What to do with Cam Cover vent (95 Sportster)

    (Title is supposed to say “What”, not “Want”) Just got my oil tank mounted and oil lines ran. Question is, what do I do with the cam cover vent hose? If I remember correctly, it was just tied to the back of the stock oil tank and vent to the atmosphere. But I’m probably wrong. Could I just grab a T and tie it into the crank case breather venting into the oil tank? Any idea is appreciated.
    Last edited by WannaBeFabrication; 07-13-2020 at 12:45 AM. Reason: Fucked up the title

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    The so-called vent line that runs from the cam cover to the oil tank (or cam chest to oil tank on a big twin) should more properly be called a pressure equalizing line, because that is what it does. It keeps the pressure or vacuum in the oil tank equal to the pressure or vacuum in the cam chest. Otherwise, the oil system would not circulate oil properly. The oil tank is not vented to the atmosphere, but the cam chest is, through another vent hose. If you try to change this system as designed, you will have oil circulation problems. The crankcase vent was originally connected to the back of the air cleaner box, but many people just vent it to the atmosphere, to keep oil vapor out of the air cleaner.

    Jim
    Last edited by JBinNC; 07-13-2020 at 5:25 AM.

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    Quote Originally Posted by JBinNC View Post
    The so-called vent line that runs from the cam cover to the oil tank (or cam chest to oil tank on a big twin) should more properly be called a pressure equalizing line, because that is what it does. It keeps the pressure or vacuum in the oil tank equal to the pressure or vacuum in the cam chest. Otherwise, the oil system would not circulate oil properly. The oil tank is not vented to the atmosphere, but the cam chest is, through another vent hose. If you try to change this system as designed, you will have oil circulation problems. The crankcase vent was originally connected to the back of the air cleaner box, but many people just vent it to the atmosphere, to keep oil vapor out of the air cleaner.

    Jim
    .... Ok so what do i do with it? Should I run it to the vent port of my oil tank and just leave the crankcase breather venting to atmosphere? or grab a T fitting and tie it into the crank case hose which i have connected to the oil tank.

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    alright, I think I got it. oil feed to the bottom of the tank, return to the top, and the vent... "Pressure equalizing line" from the cam chest to the vent bung in the oil tank. Tuck the crancase/transmission breather up somewhere to vent to atmosphere.

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    Quote Originally Posted by WannaBeFabrication View Post
    alright, I think I got it. oil feed to the bottom of the tank, return to the top, and the vent... "Pressure equalizing line" from the cam chest to the vent bung in the oil tank. Tuck the crancase/transmission breather up somewhere to vent to atmosphere.
    You are confusing two different vent lines. The transmission vent line is just that. And there is a crankcase vent line from near the front of the cam cover that originally went to the back of the air cleaner. Both these vents can be open to the atmosphere and neither can be teed into the line that runs from the oil tank to the rear of the cam cover.

    Jim

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    Quote Originally Posted by JBinNC View Post
    You are confusing two different vent lines. The transmission vent line is just that. And there is a crankcase vent line from near the front of the cam cover that originally went to the back of the air cleaner. Both these vents can be open to the atmosphere and neither can be teed into the line that runs from the oil tank to the rear of the cam cover.

    Jim
    alright... you're not answering my question at all and just dancing around the subject. The vacuum line that comes off the back of the cam cover.... where the fuck is it going? That's the question I'm asking and have been asking.

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    Quote Originally Posted by WannaBeFabrication View Post
    alright... you're not answering my question at all and just dancing around the subject. The vacuum line that comes off the back of the cam cover.... where the fuck is it going? That's the question I'm asking and have been asking.
    Answered that one in my first post. That line goes to the oil tank. It is the oil tank vent, or pressure equalizing line. Nothing can be teed into this line period. That should be clear enough.
    The line from near the front of the cam cover is the crankcase vent line, and is open to the atmosphere. It can be connected to the back of the air cleaner, or run toward the back of the bike.

    I'm sorry I am not being clear. I think it is a matter of labeling the lines so we both agree on what we are talking about. I'm not a picture person so my description will have to do. The H-D manuals kind of skip over this information too, so I can understand your confusion. I just hope I have not confused you further.

    Jim

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    The small "vent" line from the rear of the cam chest needs to go to the vent fitting on your oil tank and nowhere else. The trans vent can go to atmosphere and should not go to your oil tank. I usually just remove the hose completely. The evo sportster crankcase breathes thru the head breather bolts so there is no line coming from your cases for that. Remain calm!!!
    Last edited by BlackCloudSalvage; 07-13-2020 at 8:38 PM.

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    Damn. I forgot about the head breather thing. I've been dealing mostly with the older ones that have a crankcase vent on the front of the cam cover.

    Jim

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    Quote Originally Posted by JBinNC View Post
    Damn. I forgot about the head breather thing. I've been dealing mostly with the older ones that have a crankcase vent on the front of the cam cover.

    Jim
    Yeah I figured you had Ironhead and early Evo sporty in mind. But I agree things got confusing when he mentioned crankcase vent and T fitting Etc
    Last edited by BlackCloudSalvage; 07-13-2020 at 8:42 PM.

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    Quote Originally Posted by BlackCloudSalvage View Post
    The small "vent" line from the rear of the cam chest needs to go to the vent fitting on your oil tank and nowhere else. The trans vent can go to atmosphere and should not go to your oil tank. I usually just remove the hose completely. The evo sportster crankcase breathes thru the head breather bolts so there is no line coming from your cases for that. Remain calm!!!
    Alright, Now I got it!
    I was under the impression that the trans vent went to the vent port on the oil tank which is why I suggested the T-fitting. This is my first Harley chop build, I'm used to CB's and XS650s. Thanks for all the help.

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    Quote Originally Posted by BlackCloudSalvage View Post
    The small "vent" line from the rear of the cam chest needs to go to the vent fitting on your oil tank and nowhere else. The trans vent can go to atmosphere and should not go to your oil tank. I usually just remove the hose completely. The evo sportster crankcase breathes thru the head breather bolts so there is no line coming from your cases for that. Remain calm!!!
    Swim parallel to the shore!!

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    Quote Originally Posted by BadMonkeyMW View Post
    Swim parallel to the shore!!

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