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Thread: '90 k75s steering head bearing adjustment

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    '90 k75s steering head bearing adjustment

    So it is my understanding that the steering head bearings have to be adjusted/tightened every 5-6,000 miles. I ride a lot, so rather than pay a mechanic every month or so, I'd like to perform this service myself, but I have had a great deal of difficulty finding the appropriate information about this. Any help would be appreciated.

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    Quote Originally Posted by cniccore View Post
    So it is my understanding that the steering head bearings have to be adjusted/tightened every 5-6,000 miles. I ride a lot, so rather than pay a mechanic every month or so, I'd like to perform this service myself, but I have had a great deal of difficulty finding the appropriate information about this. Any help would be appreciated.
    Good heavens, I hope it's nowhere near that often. If it is, it's a wonder I can steer in any direction at all.
    2000 R1100RT / 1987 K75C (RIP) / Santa Clarita, CA

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    Benchwrenching PGlaves's Avatar
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    I bought a K75 in 1986. I wrecked it in 2005. In the 370,000 miles I rode that bike I adjusted the steering head bearings exactly twice. Whoever needs to adjust them every 5 or 6K miles isn't doing something right.
    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

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    Quote Originally Posted by PGlaves View Post
    I bought a K75 in 1986. I wrecked it in 2005. In the 370,000 miles I rode that bike I adjusted the steering head bearings exactly twice. Whoever needs to adjust them every 5 or 6K miles isn't doing something right.
    If I am not mistaken you have written many tech articles here, and are known far and wide for your vast knoledge on the subject of motorcycle maintenance, and repair. I actually read articles you wrote about the K75 before I owned one, so I have a tremendous amnount of respect for your opinion.
    Can you point me in the proper direction that might lead me toward a resolution. I was having an issue with my k75s where cornering at higher speeds, say 75-85mph it feels like I am riding a fish. At lower speed, if I encounter even small bumps in the road with my hands off the handle bars, or if I slap one side of the handle bars at slow speed, the handle bars will wobble quite violently. Now I understand that I shouldn't be riding without my hands on the bars, but it seems that this might be indicative of a greater problem. The rear shock is less than a year old, it is a Progressive, and the steering head bearings, and fluidbloc damper where replaced in Nov. I had the head bearings adjusted a month ago and the problem was eliminated for a while, but after a 1500 mile ride it has returned. The mechanic that replaced the bearings and fluidbloc has suggested that the issue is that my rear shock is too stiff. What confuses me is that the issue was eliminated after adjusting the bearing, and has no returned.
    Thanks for your assistance in advance.

  5. #5
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by cniccore View Post
    If I am not mistaken you have written many tech articles here, and are known far and wide for your vast knoledge on the subject of motorcycle maintenance, and repair. I actually read articles you wrote about the K75 before I owned one, so I have a tremendous amnount of respect for your opinion.
    Can you point me in the proper direction that might lead me toward a resolution. I was having an issue with my k75s where cornering at higher speeds, say 75-85mph it feels like I am riding a fish. At lower speed, if I encounter even small bumps in the road with my hands off the handle bars, or if I slap one side of the handle bars at slow speed, the handle bars will wobble quite violently. Now I understand that I shouldn't be riding without my hands on the bars, but it seems that this might be indicative of a greater problem. The rear shock is less than a year old, it is a Progressive, and the steering head bearings, and fluidbloc damper where replaced in Nov. I had the head bearings adjusted a month ago and the problem was eliminated for a while, but after a 1500 mile ride it has returned. The mechanic that replaced the bearings and fluidbloc has suggested that the issue is that my rear shock is too stiff. What confuses me is that the issue was eliminated after adjusting the bearing, and has no returned.
    Thanks for your assistance in advance.
    You are describing two problems. High speed cornering that induces what feels like a wallow is usually caused by inadequate slow speed damping (little compressions opposed to sharp bumps) as the shock compresses and rebounds under cornering loads. That might be translated as too stiff a spring because the damping of spring rebound needs to match the stiffness of the spring. If the shock is adjustable you need to increase the damping. If not, then you need to replace the shock or have it rebuilt if that is possible for your shock make/model.

    The second problem is the wobble you feel on bumps or slapping the bars. That indicates that the steering head bearings are loose and/or the Fluidbloc isn't working correctly. Since new bearings were installed I would suggest that they be readjusted. Some manuals advise readjusting steering head bearings 50 or 100 miles after they were installed. That is good practice but almost nobody does it. When the races are installed they might not be totally seated even though they seem that way. Readjusting the bearings after a run-in is good practice even without symptoms. Given you symptoms.

    1. Deal with the shock issue: adjust damping, rebuild, or replace
    2. Have the steering head bearings readjusted.
    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

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    Quote Originally Posted by PGlaves View Post
    You are describing two problems. High speed cornering that induces what feels like a wallow is usually caused by inadequate slow speed damping (little compressions opposed to sharp bumps) as the shock compresses and rebounds under cornering loads. That might be translated as too stiff a spring because the damping of spring rebound needs to match the stiffness of the spring. If the shock is adjustable you need to increase the damping. If not, then you need to replace the shock or have it rebuilt if that is possible for your shock make/model.

    The second problem is the wobble you feel on bumps or slapping the bars. That indicates that the steering head bearings are loose and/or the Fluidbloc isn't working correctly. Since new bearings were installed I would suggest that they be readjusted. Some manuals advise readjusting steering head bearings 50 or 100 miles after they were installed. That is good practice but almost nobody does it. When the races are installed they might not be totally seated even though they seem that way. Readjusting the bearings after a run-in is good practice even without symptoms. Given you symptoms.

    1. Deal with the shock issue: adjust damping, rebuild, or replace
    2. Have the steering head bearings readjusted.
    OK, I understand that the shock needs to be replaced, it is as soft as I can make it. But what I don't understand is:
    1) why did the wallow go away after the head bearings were adjusted a month ago
    2) could the stiffness of the rear shock be causing the head bearings to loosen, or is it more likely that the bearing improperly adjusted? That shock is so stiff, that it has been referred to as a piece of oak, or maple.
    Thank you again.

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    Registered User jwetering's Avatar
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    Quote Originally Posted by PGlaves View Post
    You are describing two problems. High speed cornering that induces what feels like a wallow is usually caused by inadequate slow speed damping (little compressions opposed to sharp bumps) as the shock compresses and rebounds under cornering loads. That might be translated as too stiff a spring because the damping of spring rebound needs to match the stiffness of the spring. If the shock is adjustable you need to increase the damping. If not, then you need to replace the shock or have it rebuilt if that is possible for your shock make/model.

    The second problem is the wobble you feel on bumps or slapping the bars. That indicates that the steering head bearings are loose and/or the Fluidbloc isn't working correctly. Since new bearings were installed I would suggest that they be readjusted. Some manuals advise readjusting steering head bearings 50 or 100 miles after they were installed. That is good practice but almost nobody does it. When the races are installed they might not be totally seated even though they seem that way. Readjusting the bearings after a run-in is good practice even without symptoms. Given you symptoms.

    1. Deal with the shock issue: adjust damping, rebuild, or replace
    2. Have the steering head bearings readjusted.
    Thank you for describing a problem I have been having since the start of the riding season. I also get a wallow when I corner at high speeds, especially if I encounter a bump.

    In my case - I rebuilt the front fork tubes over the winter. Actually I didn't rebuild them so much - I took the sliders off, cleaned them thoroughly, changed the oil, and changed the seals. I also changed my steering head bearing and have it tightened too what I think is satisfactory. I did not touch the back shock which is a relatively new Progressive 412.

    There's more colour. In fact the fork tubes were used. My original fork tubes were wrecked in a low speed crash. The used fork tubes were from an S and were straight and clean. I don't know what springs were inside - and I don't know what springs were inside my old tubes. One or the other could have been not stock for all I know.

    I attributed the problem to a badly cupped front tire. In the past this has resulted in wobbles when I let off the gas and let go of the handlebars - but that's not a problem this time. The wobble problem only shows up in corners. I did change my tire recently - I put on a used tire which was in pretty good shape. It definitely handled better and I thought I had it beat but just last night it gave me another wobble which has me concerned.

    So here's a question..if I overfilled the forks a bit - would that cause what we describe. I think I may have put 50 mL too much in.

    thanks
    jasper
    north vancouver

    1990 K75S

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    Quote Originally Posted by cniccore View Post
    Ithe steering head bearings, and fluidbloc damper where replaced in Nov. I had the head bearings adjusted a month ago and the problem was eliminated for a while, but after a 1500 mile ride it has returned. The mechanic that replaced the bearings and fluidbloc has suggested that the issue is that my rear shock is too stiff.
    What did the mechanic pack the fluidbloc with??

    The proper grease has not been available from dealers for years.




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