Oil everywhere! HELP...

Discussion in 'Airheads' started by immaculata, Oct 21, 2012.

  1. immaculata

    immaculata Adventurer

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    This is never a good ending to a ride...

    [​IMG]


    So i need some help to trouble shoot why the back half of my bike is covered in engine oil. As you can see my beemer is not exactly stock. There's no air box and the crank case breaths via a small K&N filter. Yesterday a mate borrowed the bike and called about 20 minutes later when he stopped and found oil all over the backend. It didn't take me long to find where the oil was coming from, yep, the crank case breather had excreted it. Thank god he stopped when he did because quite a lot of the oil ended up on the back wheel.

    Note to self: BUILD A CATCH CAN


    But why would this happen? How can i trouble shoot this?

    I've pulled the plugs thinking Rings but they look perfect.

    Any ideas?
    #1
  2. Box'a'bits

    Box'a'bits In need of repair

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    Does it smell like gearbox oil? There is a bolt at the top of the gearbox. I've had that loosen (forgotten to tighten it) a few times & the gearbox is good at spitting oil out of that - makes a hell of a mess.
    #2
  3. immaculata

    immaculata Adventurer

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    Na i don't think so. I had the crank case breather filter under the starter cover and that's where all oil has come out. I can see it's flowed out of that hole on the left side of the case that goes into the starter housing.
    #3
  4. Byron1

    Byron1 Been here awhile

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    I know it might sound like a stupid question, but has your mate overfilled it with engine oil?

    On my bike, i never fill it up to the max fill line on the dipstick as it will always end up venting into the RH carb.. or in your case the back wheel. I always fill it to about 3/4 up the dipstick marker.. no further.. reading taken with the dipstick unscrewed and resting on the filler hole.
    #4
  5. immaculata

    immaculata Adventurer

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    not a stupid question at all, i asked him exactly that. But he didn't and it's been fine for the last 2K km's i've done on it so i don't think that's an issue. Thanks though...
    #5
  6. Airhead Wrangler

    Airhead Wrangler Long timer

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    Did you fill the oil up to the full mark on the dipstick? (or farther?) Also, there's a small drainback hole just under the breather valve in the bottom of the condensing tunnel on the top of the crankcase. If that tiny hole gets blocked the tunnel fills with oil. Pull your breather valve and verify that the drain is open.
    #6
  7. immaculata

    immaculata Adventurer

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    thanks, i'll check that out tonight
    #7
  8. supershaft

    supershaft because I can

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    I fill my crank full to the full mark and rev my engine to 8k all the time and I never have more than just a little bit come out of my crank vents. I have still never noticed any airhead engine stop using oil or stop blowing a small bit out the crank vent at the half way mark or even at the add mark. I am keeping my eyes open since tons report just that.
    #8
  9. Voltaire

    Voltaire Titanium and Ceramic Hipster

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    snap....
    [​IMG]

    we pulled the gearbox out and the flywheel off.....not the main seal...

    eventually found the culprit....

    [​IMG]

    had a sort of bodged silicon gasket....

    Interesting comment earlier about oil level....

    What I think happened was at high revs ( its a race bike) the breather tube to catch bottle filled up and dripped out via the 'gasket' into the clutch......grrrr.
    #9
  10. immaculata

    immaculata Adventurer

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    is this the hole you mean? No idea how i confirm this is not blocked. Looks ok i guess? (not a bad photo for a phone!)

    [​IMG]
    #10
  11. immaculata

    immaculata Adventurer

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    Got a feeling my clutch has copped some oil too. I wasn't riding but my mate that was said it felt like the clutch was slipping.... great!
    #11
  12. immaculata

    immaculata Adventurer

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    found this shot on bmwmotorcycletech. time to start poking...


    [​IMG]
    #12
  13. pommie john

    pommie john Long timer

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    I've seen the oil spew out of the breather once ( not on my bike) but only when the rings were shot and pressurising the crankcase.
    #13
  14. immaculata

    immaculata Adventurer

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    That's exactly what I hope it's not. I guess a compression test will tell all?
    #14
  15. pommie john

    pommie john Long timer

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    I guess, but a leak down test would be better.
    #15
  16. Bill Harris

    Bill Harris Confirmed Curmudgeon

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    The breather valve is set up wrong. Align the new breather so that the reed valve opens facing "10:30 o'clock" ("12:00 o'clock" being straight ahead pointing to the front of the bike).

    --Bill
    #16
  17. pkboxer

    pkboxer Been here awhile

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    Bill, is this one facing 6 o'clock according to your description?

    What is the reason for 10:30? :ear
    #17
  18. supershaft

    supershaft because I can

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    +1
    #18
  19. Voltaire

    Voltaire Titanium and Ceramic Hipster

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    Don't be tempted by Brake Clean....I was....it worked but not for long.....getting quite fast at gear box pulling now :huh
    #19
  20. RGregor

    RGregor Been here awhile

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    Have you ever had this before? How did your friend rev the engine?

    There are engines that throw oil at high revs, others don't do it.
    Cause could be tolerances in the cast of the crankcases.
    Hartmut Lohmann (www.lohmann-tuning.de) modifies the cases in the area of the back main bearing (where the oil channel is coming from the left side) to allow better oil flow downwards between the crank and the case.
    Otherwise it may be pumped upwards into the breather entry, which is located on the left side.

    My experience:
    My first engine could be reved up to 8k and kept there for minutes (thanks to the german Autobahn) without pumping any oil. I checked the catch tank after 10,000km and found only dust.
    The second engine was built on a used R100GS base. Keeping revs up resulted in pumping oil like on Voltaire's image.
    My current engine was built with a new crankcase, modified by H.Lohmann. No pumping at all.
    It's a pity I can't compare the before/after effect directly.

    A friend had the same problem with his R100GS ever since he bought the bike.
    He had the case modified, but at the same time changed to a new piston/barrel set. No pumping any more.
    So again no direct before/after comparison possible.
    But my personal conclusion is it works.
    #20