Results 1 to 8 of 8

Thread: Where do I start??? K75S, 1986

  1. #1
    Registered User dieselyoda's Avatar
    Join Date
    Mar 2013
    Location
    Winnipeg, MB, Canada
    Posts
    547

    Where do I start??? K75S, 1986

    Huh?
    leakone.jpg

    Puddle of oil, gear oil, on the floor, some in the wheel rim, nothing clearly leaking.

    Bike is a K75S, 1986, not mine. I'm giving it some badly needed TLC for a good friend. If you look closely at this bad picture, you can see someone welded the rear end and there is a cut mark, similar to when you loose control of a cut-off saw.

    I have no idea if should call it a day and just rip it apart and tear into it. It's bizarre, it has been here for a month and today, a puddle.

    We have no history on this bike. I'm afraid he bought the bike that had a rear end ghost and now it's turned into a gremlin. Why would you weld the rear end there? It's never been crashed that we know. It did have a clutch explode two years ago, welding was required then.
    Last edited by deilenberger; 01-04-2014 at 09:55 PM. Reason: added year/model to thread title
    1997 R1100RT (Restored Basket Case) , 1981 KZ 440 LTD (Restored Basket Case)
    1986 K75S(the beutch), 1993 K1100RS (blown engine), 1997 Chev Short Box (4x4 with an LT1)
    "You can easily judge the character of a man by how he treats those who can do nothing for him."

  2. #2
    Registered User
    Join Date
    Sep 2008
    Location
    Wilmington, NC
    Posts
    2,118
    Screwed up pressing op on a rebuild maybe?

    Bet the inside is interesting

    Calling Anton....

  3. #3
    Registered User dieselyoda's Avatar
    Join Date
    Mar 2013
    Location
    Winnipeg, MB, Canada
    Posts
    547
    Quote Originally Posted by racer7 View Post
    op

    Calling Anton....
    Please don't call Anton, I want a radio from him and all the nice mitts with snot wipers are gone. What's "op"?
    1997 R1100RT (Restored Basket Case) , 1981 KZ 440 LTD (Restored Basket Case)
    1986 K75S(the beutch), 1993 K1100RS (blown engine), 1997 Chev Short Box (4x4 with an LT1)
    "You can easily judge the character of a man by how he treats those who can do nothing for him."

  4. #4
    Registered User
    Join Date
    Nov 2013
    Location
    Plantation, Florida
    Posts
    9
    If you don't see the housing leaking I bet the seal behind the brake disk is gone with possibly the bearing as well if you're unlucky. Take the wheel and the disk of and tell us what you see.

    Or it could be a leak from your caliper. Could be very simple.

    Regards, Rene

  5. #5
    Benchwrenching PGlaves's Avatar
    Join Date
    Oct 2003
    Location
    "Big Bend" TX
    Posts
    8,648
    Here is my best long distance photo viewing guess:

    The mar on the final drive case happens to be right where the tapered roller bearing on the crownwheel (ring gear) shaft is located. If the case was cut or broken and welded at this location it is purely pot-luck whether the internal machining for the roller bearing outer race is perfectly true with the machining in the housing cover for the big ball bearing on the other end of the crownwheel shaft.

    If not it will stress the ball bearing and probably damage the seal in the housing cover. That appears to be the source of the leak. The immediate short term cure is to remove the housing cover, examine and possibly replace the ball bearing, and certainly replace the seal and big O ring. My problem with this approach is that if the roller bearing fails to sit true in line with the ball bearing the drive will just self destruct again.

    It that was on my bike I would do one of two things: I would get a used final drive with a good case and check it out internally, and then use it; or get one and rebuild it with bearings and seals in the new case.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
    http://www.bigbend.net/users/glaves

  6. #6
    Registered User dieselyoda's Avatar
    Join Date
    Mar 2013
    Location
    Winnipeg, MB, Canada
    Posts
    547

    Yeah, I knew somebody was going to tell me what I already knew.

    Quote Originally Posted by PGlaves View Post
    Here is my best long distance photo viewing guess:

    The mar on the final drive case happens to be right where the tapered roller bearing on the crownwheel (ring gear) shaft is located. If the case was cut or broken and welded at this location it is purely pot-luck whether the internal machining for the roller bearing outer race is perfectly true with the machining in the housing cover for the big ball bearing on the other end of the crownwheel shaft.

    If not it will stress the ball bearing and probably damage the seal in the housing cover. That appears to be the source of the leak. The immediate short term cure is to remove the housing cover, examine and possibly replace the ball bearing, and certainly replace the seal and big O ring. My problem with this approach is that if the roller bearing fails to sit true in line with the ball bearing the drive will just self destruct again.

    It that was on my bike I would do one of two things: I would get a used final drive with a good case and check it out internally, and then use it; or get one and rebuild it with bearings and seals in the new case.
    Thank you Paul. I think you are dead on the money. I was hoping somebody might have the mojo to change my mind about what I thought needed to be done.
    1997 R1100RT (Restored Basket Case) , 1981 KZ 440 LTD (Restored Basket Case)
    1986 K75S(the beutch), 1993 K1100RS (blown engine), 1997 Chev Short Box (4x4 with an LT1)
    "You can easily judge the character of a man by how he treats those who can do nothing for him."

  7. #7
    A bozo on the bus deilenberger's Avatar
    Join Date
    Mar 2003
    Location
    Spring Lake NJ, USA
    Posts
    7,707
    Yoda - please review: http://www.bmwmoa.org/forum/showthread.php?46057 - I'll add that info to your thread title. It does make a difference, there are variations on years/models.
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders New Sweden BMW Riders
    '07 R1200R (current ride) and some bimmers.. and a Porsche

  8. #8
    Registered User dieselyoda's Avatar
    Join Date
    Mar 2013
    Location
    Winnipeg, MB, Canada
    Posts
    547

    Thanks, me bad, just forgot.

    Quote Originally Posted by deilenberger View Post
    Yoda - please review: http://www.bmwmoa.org/forum/showthread.php?46057 - I'll add that info to your thread title. It does make a difference, there are variations on years/models.
    Still looking for someone to convince me that I'm wrong. Oh well, add it to my R1100RT tranny rebuild...............
    1997 R1100RT (Restored Basket Case) , 1981 KZ 440 LTD (Restored Basket Case)
    1986 K75S(the beutch), 1993 K1100RS (blown engine), 1997 Chev Short Box (4x4 with an LT1)
    "You can easily judge the character of a man by how he treats those who can do nothing for him."

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •