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Thread: 93 K75S Fluid-Bloc Steering Damper

  1. #1
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    93 K75S Fluid-Bloc Steering Damper

    Do your handlebars start shaking in resonance, that is the amplitude increases unless corrected, when both hands are off the handlebars while riding?
    1993 K75S Mystic Red Pearl
    2007 K1200GT 997 Blue

  2. #2
    Registered User jwetering's Avatar
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    Sometimes when I let off the throttle it does, but not as a rule. There's a thread already on this not so far down the list. Consensus seems to be that tires are usually the problem, or a bent wheel.

    The damper plays a minor role...apparently.
    jasper
    north vancouver

    1990 K75S

  3. #3
    Dances With Sheep GREGFEELER's Avatar
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    Quote Originally Posted by ghyber View Post
    Do your handlebars start shaking in resonance, that is the amplitude increases unless corrected, when both hands are off the handlebars while riding?
    Under what conditions? Going straight or in a corner? How fast? Loaded how? Etc. In answer to your question - no. That shouldn't happen. The Klassic K-bikes can have a undulation (wobble) in corners like any other bike if there are problems with loose fork head or swing arm bearings, a worn rear shock, or so on.
    Greg Feeler
    BMW MOA Director & Ambassador
    1972 R75/5, 1990 K75, 1990 K1, 1992 K75S, 2003 K1200RS

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    Quote Originally Posted by GregFeeler View Post
    Under what conditions? Going straight or in a corner? How fast? Loaded how? Etc. In answer to your question - no. That shouldn't happen. The Klassic K-bikes can have a undulation (wobble) in corners like any other bike if there are problems with loose fork head or swing arm bearings, a worn rear shock, or so on.
    Straight and level highway at cruising speed of 60mph; all bags on, ie. top case + side cases with very little load in any.
    1993 K75S Mystic Red Pearl
    2007 K1200GT 997 Blue

  5. #5
    Dum vivimus vivamus ted's Avatar
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    Don't forget a tired or poorly adjusted rear shock.

    A lo of time things like this can be caused by more than one thing which together make the problem really noticeable. From what I have seen adjusting/replacing steering head bearings, making sure tires are properly balanced, and spending some time checking out the front and rear suspension (especially fork alignment, fork oil & rear shock) usually does the trick.
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

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    Dances With Sheep GREGFEELER's Avatar
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    Quote Originally Posted by Ted View Post
    Don't forget a tired or poorly adjusted rear shock.

    A lo of time things like this can be caused by more than one thing which together make the problem really noticeable. From what I have seen adjusting/replacing steering head bearings, making sure tires are properly balanced, and spending some time checking out the front and rear suspension (especially fork alignment, fork oil & rear shock) usually does the trick.
    Good list. One of the K75s has a wobble in high speed corners, and has had off and on over the years despite a new Progressive rear shock, fork head bearings a couple of years ago which included a fork and fluid-bloc dampener service, detailed "tuning" of fork oil weight and level, and good tires. Today I'm on a mission to find the cause(s): checking fork alignment and swing arm alignment and bearing adjustment, and checking front to rear wheel alignment. Like Ted said, sometimes is not one thing, but a combination of several that have gotten "out" just a bit over time.
    Greg Feeler
    BMW MOA Director & Ambassador
    1972 R75/5, 1990 K75, 1990 K1, 1992 K75S, 2003 K1200RS

  7. #7
    Dum vivimus vivamus ted's Avatar
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    Give this 3-part series a look:
    http://youtube.com/watch?v=tVWHfyG4jB4

    Planning on working on my K75RT front end when I get the cast off - new fork springs, gators, Seals, new head bearings, and a thorough fork check.

    Now if I could only find an Ohlins or Fox TC for the rear
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

  8. #8
    Dale Rudolph
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    I had the steering head bearings replaced about a year ago on my 92 K75RT at Hansens BMW in Medford, Oregon. Craig Hansen has been working on BMW"s
    since he opened in 1972. When he got the steering assembly apart, he let me
    know that one of the parts in the steering dampner was worn out and that he
    could not find replacement parts for it. He said that if it were his bike he would
    have no hesitation just leaving the steering dampner out. The story he told me is that the steering dampner was made because of problems with the steering in the K-100 models, mostly in the heavier K-100 RT . The lighter K75 models did
    not show the steering problems but as both the K-75 and K100 came off the same
    assembly line, they put the dampners in all of them. I now have over 3,000 miles
    on the bike without a steering dampner in it and have never had any problems with it.

  9. #9
    3 Red Bricks
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    Quote Originally Posted by Ted View Post
    Give this 3-part series a look:
    http://youxube.com/watch?v=tVWHfyG4jB4

    I hate to say this about a fellow S owner BUT;

    That guys videos DRIVE ME NUTS!!!! I've seen several of them before.

    The editing is TERRIBLE. They are full of partial thoughts, out of order info, misinformation and non-sequiturs. If you tried to do any of those projects by following his directions, you'd be in deep do do.

    He provides enough info to make people who don't have a clue, think he really knows his stuff, but in such a fashion as to completely confuse them. And he does it in a way that completely frustrates people that DO know what he's trying to accomplish.

    I would suggest that a thorough reading of the Clymers chapter on what ever project you're trying to accomplish is WAY more beneficial.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  10. #10
    3 Red Bricks
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    Quote Originally Posted by RUDYJO View Post
    When he got the steering assembly apart, he let me
    know that one of the parts in the steering dampner was worn out and that he
    could not find replacement parts for it.
    There are only two parts to the damper: The damper ring:

    02 46 51 2 310 218 DAMPER RING FOR FLUIDBLOCK 0.17 1 $30.46

    Still available.


    and the grease:

    07 58 9 058 193 LUBRICANT SILICONE 300 - 10G 0.03 X NA

    The grease is no longer available. Dow Corning Silicone High Vacuum Grease is a viable substitute.




    Last edited by 98lee; 04-22-2012 at 10:53 PM.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

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

  11. #11
    Dum vivimus vivamus ted's Avatar
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    Quote Originally Posted by 98lee View Post
    That guys videos DRIVE ME NUTS!!!!
    LoL - yes, it is exceedingly hard to follow, and the info on the IBMWR site is much more useable. That said, I found the parts about checking the forks for tweaks and alignment helpful and not really covered well anywhere else. I will be checking things carefully when I do the dissemble and reassembly, though I don't think I will go so far as to ream out the fork brace holes

    As ever, read a lot of different sources, ask a lot of questions, go slowly, and don't tighten the oil filter more than a half turn beyond hand tight
    Ted
    "A good stick is a good reason"
    1994 K75RT
    Moto Pages

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    Quote Originally Posted by Ted View Post
    ...and don't tighten the oil filter more than a half turn beyond hand tight
    Ahhh, famous last words of wisdom. Did I see this part in Clymer's in bold print? Or was it the Hayne's manual? So, what happens that is so terrible if overtightened?
    1993 K75S Mystic Red Pearl
    2007 K1200GT 997 Blue

  13. #13
    rabid reader dbrick's Avatar
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    Quote Originally Posted by ghyber View Post
    So, what happens that is so terrible if overtightened?
    If they're too tight, filters are hard to remove because the regular fluted socket slips pretty easily. Because the filter is up in a recess in the sump, you can't easily use a strap wrench and may have to resort to driving sheet metal screws in the end of the filter to provide a purchase.
    David Brick
    Santa Cruz CA
    2007 R1200R

  14. #14
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    Hijack...

    Ted:

    What's with the cast?

    Larry Johnson
    El Paso

  15. #15
    Dances With Sheep GREGFEELER's Avatar
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    Check frame alignment

    Not to highjack this thread, but to add something to check to the list.

    Saturday I took my 1990 K75 on a very spirited ride on a nice piece of local twisty road. In some high speed sweepers (>90mph) I was getting a nasty wobble that seemed to be self-reinforcing once it got started. Very disconcerting.

    Yesterday I checked the rear swing arm and front fork free play and didn't find any obvious problems. So I checked the fame alignment by removing one frame bolt at a time to see if there was a gap between the fame and engine or transmission. By looseing all the frame bolts and shaking the bike I found that the right rear (bottom), right center (bell housing), and left front engine frame mounts all exhibited a gap once the bolts were released. The left rear and front right mounts were aligned. A quick trip to Ace Hardware and I had some .77 mm thick washers which were the right thickness, diameter, and hole size to shim these gaps.

    A spirited test ride today revealed that about 75% of my problem was gone. During 90 MPH+ hard corners I could get a very small amount of "hinge-in-the-middle" effect, but it did not continue to increase once started like yesterday, and was directly proportional to throttle input and speed. If I backed off - it did, which was not the case yesterday. Big improvement!

    The rear tire is basically worn out, so next I'm going to test with a new tire, and then remove the bags and rear tail trunk to see if they are catching air off the Pichler fairing at those speeds.

    My theory is that that relatively small amount of preload on the frame was enabling it to act like a spring and begin to resonate once I got any instability, much like a classic fork head speed wobble. I also noticed the the overall handling was improved, and a harshness in the suspension when hitting rough pavement was eliminated.

    I had heard that it was good to check the frame alignment on a classic K-bike, but this is my first direct experience doing so, and I'm very pleased with the results.
    Greg Feeler
    BMW MOA Director & Ambassador
    1972 R75/5, 1990 K75, 1990 K1, 1992 K75S, 2003 K1200RS

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