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Thread: Vibration at high speed/rpms in '90 K75S

  1. #16
    Debbie's Servant Lee's Avatar
    Join Date
    May 2003
    SW Iowa
    Quote Originally Posted by PGlaves View Post
    Yes but post 12 by a different poster with a similar issue was posted just today - new and fresh.
    2016 R1200RS
    MOA # 30878
    Past BMW Bikes: 2011 K1300S, 2003 K1200RS, 1991 K75S, 1987 K75T, 1984 R100RT

  2. #17
    3 Red Bricks
    Join Date
    Jan 2007
    Pleasanton, Ca.
    Quote Originally Posted by 20774 View Post
    Paul -

    The clutch I put in my /7 a few years ago came from BMW and there were no marks. It was my understanding they come balanced and there's no need to worry about spacing. However, if I had a clutch already installed with no issues, I would certainly mark the existing orientation for reassembly.
    The clutch for the /7 probably comes without marks because they are "close enough" for a /7. A good running /7 vibrates more than a poor running K75, so the tolerances would be looser.

    If you don't believe me, take a nickel and balance it on edge somewhere on the bike. Reach over and start the bike. Then slowly raise the throttle to 3000 rpm. If you can get near there, your bike MAY be near as smooth as a typical K75.


    Ride Safe, Ride Far, Ride Often

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

  3. #18
    Quote Originally Posted by 20774 View Post
    The "new poster" says he replaced the clutch. True, we don't know what that means, but I take it as the whole shebang was replaced. If a person replaced only the fiber disk, seems like they would go so far as say that. But, it's hard to read all of what is meant by just the typed word in this case.

    Even still, if he did just replace the fiber plate, they come these days with no markings as far as I know. Back to what I said, if disassembling the entire clutch pack, and replacing say only one item, it would certainly be best to put the old items back in their original orientation. The replaced item would have no markings so it's just put in and you take what you get.
    I replaced just the clutch fiber disk. The bike had been sitting for a lot of years before I bought it and was slipping on hard acceleration. The fiber disk was cracked and glazed. I did mark everything and reassembled as instructed in the Haynes manual.

    Upon further searching on this forum, it's possible it is only the monkey nuts (assume they are original). I had ridden it around a bit before the kids took it over and am sure I would have noticed the vibration. Although most of my riding was back road twisties (or as best we have of those here in WI) and I may not have noticed. I road it back from Phoenix and during the long hours of droning it was really evident.

    Thanks all for the replies and advice. Will update again this winter after I get it torn apart and repaired.
    I have my GSA to bide me over until then.


  4. #19
    Liaison 20774's Avatar
    Join Date
    Sep 2005
    San Antonio, TX
    I had to do some searching to find out what "Monkey nuts" were!
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  5. #20
    Hopefully your search wasn't on Google. That might return some odd information.

  6. #21

    Vibration (very likely) solved

    Yup, monkey nuts. And the alternator cup (clutch housing on parts fiche) had all three vanes broken off. And the driving dog on the back of the engine had two vanes broken off. All were still in the cup and apparently jammed up enough to keep the alternator turning during my 2200 mile ride home from AZ. Dodged a bullet.

    $15 for a used driving dog and $17 for a set of new monkey nuts from fleabay. Had been given an alternator from someone cleaning out their old parts stash - that has a perfect cup still installed. Should have it back together soon but won't be able to test for a few months (doG, I hate winter).

    Will post pics soon. They're kind of ugly.

  7. #22
    Registered User
    Join Date
    Apr 2013
    Southern California USA


    Quote Originally Posted by 20774 View Post
    I had to do some searching to find out what "Monkey nuts" were!
    Yeah, me too, first time i read it. Lots of weird lingo to be learned with these k bikes. After a year or so with my first k bike, I'm starting to become fluent in Kspeak.

  8. #23

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