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Thread: K75S Clutch Spline Lube Reveals Oil in Intermediate Housing

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    Registered User detbmw's Avatar
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    K75S Clutch Spline Lube Reveals Oil in Intermediate Housing

    This afternoon Jeff488 & I pulled the transmission off of my '88 K75S. We immediately noticed oil around the walls of the intermediate housing. Not on the clutch, and not on the transmission. It seems to be engine oil coming from maybe the Rear Main Seal? Oil was not pouring out, it was just coating the walls and the bottom.





    We have a couple questions:
    1) Is this if immediate concern? Can the bike be ridden for another 25K before replacing the rear main seal (if that is the problem), or should this absolutely be fixed before the bike is ridden another mile?

    2) Can the rear main seal be replaced from outside the engine if we pull the clutch off?

    Also, we happened to remove the clutch release arm and about 1/2 oz of oil spilled out of the boot. Should we be concerned about that?
    Last edited by detbmw; 12-16-2012 at 12:28 AM.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

  2. #2
    3 Red Bricks
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    The oil is coming from either the rear main seal or more likely the o-ring that seals the nut that holds on the flywheel (clutch housing). It's hard to say how long you could go until it trashes your clutch. If you replace both of them now, you probably won't need to buy a clutch later. Clutches on these bikes last a VERY long time UNLESS they get oiled down.


    Yes, you can replace the rear main seal with only removing the clutch and clutch housing. WARNING! Mark the orientation of the clutch housing, pressure plate and clutch cover to each other BEFORE removing to maintain the balance. VERY IMPORTANT!!!


    There will always be some oil inside that boot. Just make sure the boot isn't torn.



    Last edited by 98lee; 12-15-2012 at 03:24 PM. Reason: spelling
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  3. #3
    Registered User detbmw's Avatar
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    Quote Originally Posted by 98lee View Post
    The oil is coming from either the rear main seal or more likely the o-ring that seals the nut that holds on the flywheel (clutch housing). It's hard to say how long you could go until it trashes your clutch. If you replace both of them now, you probably won't need to buy a clutch later. Cltches on these bikes last a VERY long time UNLESS they get oiled down.


    Yes, you can replace the rear main seal with only removing the clutch and clutch housing. WARNING! Mark the orientation of the clutch housing, pressure plate and clutch cover to each other BEFORE removing to maintain the balance. VERY IMPORTANT!!!


    There will always be some oil inside that boot. Just make sure the boot isn't torn.



    I found an o-ring (BMW Part: 11211460456) but I'm having trouble finding the rear main seal on microfiche.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

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    3 Red Bricks
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    06 11 11 7 666 186 SHAFT SEAL - 50X80X10 0.09 1 $30.60

    This is a teflon output shaft seal. Located at the back of the engine block, in front of the flywheel. Sometimes called a rear main seal. Price is based on a quantity of ONE.




    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  5. #5
    Registered User detbmw's Avatar
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    Quote Originally Posted by 98lee View Post
    06 11 11 7 666 186 SHAFT SEAL - 50X80X10 0.09 1 $30.60

    This is a teflon output shaft seal. Located at the back of the engine block, in front of the flywheel. Sometimes called a rear main seal. Price is based on a quantity of ONE.




    Thanks! I'll get my parts ordered tomorrow morning.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

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    Registered User jwetering's Avatar
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    This happened to me as well.

    The o-ring was leaking badly already when I bought my bike last year. I sort of ignored/failed to investigate the issue, and by the end of the season my clutch was slipping badly.

    In the end it was 6 of one half a dozen of the other.

    You have to remove the clutch entirely to repair the o-ring and main seal, and for the price (less than $60) it was a no brainer to replace the clutch anyway, so it didn't matter that it was ruined.

    I could have done it cheaper still...the clutch hardware was fine, it was only he clutch friction plate that was ruined.

    Don't panic, but do fix it.
    jasper
    north vancouver

    1990 K75S

  7. #7
    Aspiring Profligate jeff488's Avatar
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    We got the clutch, etc. off today and found that the main seal is OK and the "o" ring was leaking.
    Looks like everything will go back together pretty easily.
    Holy foot-pounds, Batman. 140nm of tight! Somebody will have to hold the bike upright.

    One other question I have is about the splines.
    The input shaft splines have very little wear. I can barely feel any ridge with a dental pick. However, the friction plate splines are worn considerably more, as if the metal is softer.
    That's a good thing, I guess, as the part is a good bit less expensive.

    Is that the case, that the friction plate is softer?

    Also the friction plate measured about 5.17mm, so there is plenty of life left in it.

    Thanks for all the info.
    Jeff
    '04 Silver R1150RT "Big Oel". '05 Yellow KLR 650
    '00 Red Suzuki Bandit 600
    '65 Allstate/Puch 250 twingle
    "I just want somewhere to ride and food when I get there."

  8. #8
    Registered User detbmw's Avatar
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    Update

    I received my o-ring and clutch replacement bolts & washers from Bob's yesterday, so we have the clutch back together, the clutch splines lubed - looks like the first time since 1987 - and the transmission and starter back on.

    This afternoon we are planning to reassemble the rest of the bike.

    Jeff488 build a Moto Tranny Trolley to move the transmission around on (see below), it worked out pretty good, as long as we weren't bumping into it trying to knock it over. Jeff eventually bungied the transmission to the trolley and C-clamped the trolley to the lift.

    tranny_trolly1_zpsbad1b4c4.jpg

    Thanks for the feedback, I feel a lot better about taking off cross-country for a rally on the K-bike next July.
    Last edited by detbmw; 12-19-2012 at 02:27 PM.
    Rich
    Night Black 2000 R1100RT
    Marakesh Red 1988 K75S "The S is, by far, the finest-handling BMW we have ever ridden." Motorcyclist, November 1986

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