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Breather Oil

Discussion in 'Motorcycle Tech Talk' started by Hogdog, Apr 15, 2006.

  1. Hogdog

    Hogdog Active Member

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    What causes motor oil (significant quantity) to come through the breather when the engine is running. Earnestine is a 89 ultra with stock carburator. Oil seem to be coming to the breather from a vent in crankcase.
  2. chucktx

    chucktx Moderator Staff Member

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    does the bike sit for long periods before starting?? if so it could be wet sumping.
    an over fill can cause this problem
    excessive crankcase pressure will cause this problem
    a bit more checking needs to be done to determine the reason for the loss of oil
    chuck
  3. SPORSTERBOY

    SPORSTERBOY New Member

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    Location:
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    On The Newer Evo Egines They Eleminated That Line From Your Case To The Air Cleaner. On My Sporty The Old Hose Is Now Hollow Bolts Mounted Through The Heads. When I Replaced The Air Cleaner With A Small Round Free Flow, I Made Little Filters For The Holes. They Make A Cross Over To Do The Same Thing. Depending What The Laws Are Where You Live, You Can Get A Crank Case Filter And Run It Under The Bike To Keep The Oil Out Of The Air Cleaner.
  4. Hogdog

    Hogdog Active Member

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    Thanks Chucktx,
    Here's the scoop,
    Earnestine has been down for the winter undergoing a pretty extensive repair. The disassembly of the engine was not part of the repair!! Among other things the last time she was serviced the oil screen cap screw was replaced with a hex head cap, difficult to remove from the crankcase recess. I took it out, the o ring and little filter. I was painting her jugs, so I put a pan head screw over the crank case opening to shield from paint. Next day there is oil all over the floor, somehow it is siphoning out, how can this be?? Come to think of it the oil tank is higher then the crankcase. I returned the oil filter screen, o ring and replace cap with stock slotted cap. Next I returned the chrome vent pipe and attach to the breather. Can either of these things cause an excessive crankcase pressure to blow oil?? I suspect something is wrong with the oil screen?? By removing the crankcase cap screw did this allow oil to end up where it should not have been?? Any Clues??

    Thanks
  5. Hogdog

    Hogdog Active Member

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    Oil Breather

    Thanks sportserboy for your help,

    To heck with the EPA laws, my chick is making my life miserable about the oil on the garage floor, lol. This is a pretty good size puddle, a lot more than normal. Her, That is earnestines not the chicks, breather has always been a mess, I think maybe I will yank out the crank case to breather vent!!

    Thanks
  6. chucktx

    chucktx Moderator Staff Member

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    check in your service manual for the check valve from the oil tank.....it may be sticking. i dont think just changing the cap and screen would cause your wet sumping.....the check is probably the guilty part.
    chuck
  7. CD

    CD Guest

    Here is a little more info.

    A: This is a crank case breather, not a nose breather. Nose breathers were released in '93.
    B: You are sumped up. Adding more oil without getting the oil out of the crank case first is just going to add to the puddle. The oil has no place else to go. Oil returns to tank, tank vents to engine, excess oil flows through vent to engine and gets pushed out the vent.
    C: Like Chuck says, you probably need to reseat the check ball. Look in your service manual and you can see which one. Might be a piece of debris or a scored seat. While sitting, oil leaked past the check bell and ended up in the sump. Before starting, you checked your oil an added some. Now, you have that amount too much in the engine.

    I would drain the oil and seat the check ball. Add two quarts of oil and start it up looking for return oil. After you know all of the oil in the sump is returned, you can either top off or change it out and add fresh oil.

    You can also use a catch can and keep it serviced and you will not have any drips after you fix the problem.

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