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Thread: Steel hose in oil cap, thoughts?

  1. #11
    Join Date
    Jun 2010
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    Kenya
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    Quote Originally Posted by bitzz View Post
    Inadequate crankcase ventilation leads to a pressurized crankcase resulting in "ring flutter", where the rings bounce in their slots, killing ring seal.
    Not really a problem with a stock GS with 0.125" thick rings. Modern rings are much thinner, and much more flexible, usually about 0.040" thick.

    Top fuelers, and other motors that get regular teardowns will run a vacuum pump, keeping negative pressure in the crankcase. The idea being the vacuum sucks the rings down and holds them in the bottom of the ring slot.
    The rings don't last very long at negative 3 bar.
    Thinking about this, how do you measure to a figure like negative 3br? I understood that once a vacuum is achieved that's it there would be nothing left to measure and that would be zero.
    I imagine that the rings suffer because the vacuum lowers the boiling temperature point so that the efficiency of the oil is changed massively, rings rely on mist to lubricate and a vacuum would surely affect that especially in a hot engine?
    Just asking, not challenging.
    The ring flutter is interesting


    Don't say can't, as anything is possible with time and effort, but, if you don't have time things get tougher and require more effort.

  2. #12
    Join Date
    Jul 2013
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    Wexford, Ireland
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    Sure you guys are not overthinking this?
    I have one on the 850 so I don't have to bend over to top off the oil.
    The old knees aren't what they used to be.
    80 GS850GT
    79 Z400B

  3. #13
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    Mar 2015
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    Toronto, Ontario, Canada
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    1980 GS1100E

  4. #14
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    Jun 2017
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    Sandy, Utah
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    I've been advised that the big bore kit (1100 cc high compression Wiseco pistons) may be causing the gaskets on my GS1000 engine to not seal correctly due to higher than stock crankcase pressures. I've been blowing gaskets & seals left and right since getting the bike back on the road after a number of years in storage, leading to oil leaks. The stock breather may be inadequate for this application.


    So, one of these clutch cover mounted crankcase breathers is now on its way. Now need to source and mount an oil catch can....or maybe just put a filter on the end of the braided hose. We'll see.

    Last edited by 80GS1000; 08-26-2020 at 04:50 PM.

  5. #15
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    Jul 2009
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    New Zealand
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    You're putting at patch on it rather than sorting the problem.
    If you're getting high crankcase pressures I'd look at the rings. If it's been laid up for some time you could have had rust on the bores.

    Wiseco big bores are not known for giving problems. None of the many I've done have had this problem.

  6. #16
    Join Date
    Mar 2015
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    Toronto, Ontario, Canada
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    Quote Originally Posted by 80GS1000 View Post
    So, one of these clutch cover mounted crankcase breathers is now on its way. Now need to source and mount an oil catch can....or maybe just put a filter on the end of the braided hose. We'll see.
    Might get one as well, since I'm riding high speed highways most of the time it probably wouldn't hurt. Also curious what to do with the other end of the hose, if it's possible to connect it to top end breather or just bolt it up.
    1980 GS1100E

  7. #17
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    Jul 2013
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    Anyone ever started up with the filler cap off?
    80 GS850GT
    79 Z400B

  8. #18
    Join Date
    Sep 2012
    Location
    Ireland
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    Quote Originally Posted by Brendan W View Post
    Anyone ever started up with the filler cap off?
    I've looked down and discovered I'd forgotten to put it back on and my right leg is waterproofed.
    ---- Dave
    79 GS850N - Might be a trike soon.
    80 GS850T Single HIF38 S.U. SH775, Tow bar, Pantera II. Gnarly workhorse & daily driver.
    79 XS650SE - Pragmatic Ratter - goes better than a manky old twin should.
    92 XJ900F - Fairly Stock, for now.

    Only a dog knows why a motorcyclist sticks his head out of a car window

  9. #19
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    Quote Originally Posted by Grimly View Post
    I've looked down and discovered I'd forgotten to put it back on and my right leg is waterproofed.
    A kind of poor man's dry sump design?
    80 GS850GT
    79 Z400B

  10. #20
    Join Date
    Sep 2012
    Location
    Ireland
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    Quote Originally Posted by Brendan W View Post
    A kind of poor man's dry sump design?
    It sprays out but not a deluge. Just enough to be a nuisance, and of course a danger to engine longevity if it goes on long enough.
    ---- Dave
    79 GS850N - Might be a trike soon.
    80 GS850T Single HIF38 S.U. SH775, Tow bar, Pantera II. Gnarly workhorse & daily driver.
    79 XS650SE - Pragmatic Ratter - goes better than a manky old twin should.
    92 XJ900F - Fairly Stock, for now.

    Only a dog knows why a motorcyclist sticks his head out of a car window

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