Air out of OIL Overflow .. Occational oil

Discussion in 'Oil' started by criminal0, Sep 12, 2009.

  1. criminal0

    criminal0 New Member

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    '89 FLHTC (Ultra Classic), about 100,000miles;
    I am told it had a rebuild about 20' ago .. alltough it sounds kinda 'ticky' .. hrmm .. (but thats another issue) ..


    I am sure this has been covered in the fourms .. but i was unable to locate it

    Its my first Harley ... be gental ..

    I have noticed 2 things that are starting to bother me the more i think about them;

    1) during almost every run, i notice that i have small amounts of oil leaking out of the OIL overflow tube when it idles for a few mins - mostly when its COLD, sometimes when its warm.
    i seem to get a misty looking spot of oil on the ground (directly underneath the overflow tube) the overflow tube seems al always have a few oil drips hanging off it. There is never and visible smoke or misting.
    I have only had ALOT of oil dump out of the tube 2 times. Once was when after it sat for about 1yr at start up (when i bought it) .. the 2nd time was after servicing and it was up on a center-stand .. i am not too worried about this (should i be?)

    2) MOST CONCERNING -- i have AIR flow coming out of the Oil overflow tube at all times (when the bike is running)... is this a Harley thing? or is something wrong?


    NOTE: the bike is NOT overfull with oil; i have played with varying oil levels for weeks with no difference. it have no performace issues, it runs strong with no other oil/gas leaks or issues (other than i need the carb tuned - but who doesn't!! - lols)

    What should i be investigating? is this normal to have AIR-FLOW out that OIL overflow tube?

    I am semi-panicing here .. any input is welcome!

    Thx
    Mike (Criminal Zero)
    Ontario, Canada
     
  2. glider

    glider Veteran Member

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    Take a compression test to see what shape the rings are in. Usually the air out the oil fill is engine blow by past the rings.
     
  3. criminal0

    criminal0 New Member

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    ok, i bought a compression tester; ill test tonight ..

    what is a ~normal~ compression for my bike?

    thx
     
  4. glider

    glider Veteran Member

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    Pressures depending on the carbon buildup in the engine and ring condition could range between 130-160lbs with throttle full open and slide in the carb held up if you have a CV carb.
     
  5. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    I'm no expert on your year of bike but if by oil overflow you mean the crankcase breather then i wouldn't think it unusuall to get air puffing out of it as when the pistons go up and down they will displace the air beneath them

    once upon a time crank case breather tubes on bikes were vented to air usually poking out the bottom of the bike somewhere and would usually drip a little oil this would be condensed oil vapour as the oil vapour cooled in the breather tube the oil would turn back to a liquid and drip out the breather tubes

    at some stage things changed and crank case breathers were routed back into the air box so that any oil vapour could be fed through the engine and burn during combustion (this seems to create a whole set of problems of its own)

    i hope this helps

    Brian
     
  6. criminal0

    criminal0 New Member

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    after talking with a TON of people this seems to be true for my year/model.
    What a HUGE load off my mind!!

    I will do a compression test regardless, perhaps a leak down test as well, just to check its general health. I understand that there is some type of pressure spring and ball that is known to get stuck/fouled .. i will look into that too.


    Thx again guys for all the info
    Criminal0