adjusting R100GS steering head bearings?

Discussion in 'Old's Cool' started by Solo Lobo, Jul 27, 2005.

  1. Solo Lobo

    Solo Lobo airhead or nothing

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    Anyone, can you give me some directions?

    I'm experiencing some front end weave (head shake) at around 75-80 depending on wind. Tried adding more preload to the rear shocks, no change, fork oil is brand new 15wt with the correct volumes, springs are very young progressives...
    #1
  2. Frank Warner

    Frank Warner Traveller

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  3. ozadvntr

    ozadvntr Planning that trip, again

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    What's your tyre like? tread pattern wear etc.

    Mick
    #3
  4. Rubber Cow

    Rubber Cow GS Dork

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    Hi Solo,
    Some questions.....
    How much weight do you have on the back of the bike when this happens?Is it loaded or unloaded?
    -What preload spacers are you using?
    -How much do you weigh?
    -What tires are you riding?
    -What air pressure are you running?
    FYI, the Gold Valve made the headshakes disappear unless the bike has a lot of gear on the rack and is kind of overloaded.
    Hope this helps.
    Cheers,
    Jorge
    #4
  5. Solo Lobo

    Solo Lobo airhead or nothing

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    Good questions,

    I'm running Gripsters front an rear, noticed this behavior at 1,000 miles and recently with about 3000 miles one 'em. Both are at 35 lbs/in2 (checked the pressure before riding to and out of the mountains when this happened). This has only happended when running the bike 75-80 mph with the boxes on the back, first loaded BMW panniers (last year) and yesterday with happy trails that were carrying less then 5 lbs of junk in each. Haven't noticed the problem when running these speeds (w/ boxes) on the flat as much, mostly climbing or decending long grades)

    I weight around 175 lbs with my gear on.

    I haven't measured the preload spacers in with the progressives... if there are any in there.

    The rear shock is a works performance that I bought from ctn Ron, He changed the gas/oil in it and it seems to work nicely.

    Thanks!

    #5
  6. UnrEgistered

    UnrEgistered Adventurer

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    A similar if not identical problem was discussed years ago in the bmw-gs forum and for at least one of us the problem turned out to be that our hard bags with age and time would loosen up at the plastic mounting points.
    If the front end wobble only happens with your bags on and over 75mph, see if the bags might be loose in the mounts. If so, try cutting some 1/2" rubber hose lengthwise and use it on the rack mounts to take up any loose slack. Was a cheap and easy fix for my front end wobble.


    unreg'd
    #6
  7. Solo Lobo

    Solo Lobo airhead or nothing

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    Thanks Un,

    I'm running Happy trails panniers on touratech racks with TT mounting hardware... so I think all is good but will verify tonight!

    SL

    #7
  8. LoFlow

    LoFlow Been here awhile

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    I,ve had the same problem from day one after installing tt bags. Ohlins rear, Wurth fronts, steering head bearings adjusted, loaded and unloaded. Numerous tire combos, passenger, no passenger. I give up. Above 75 mph but lower when bucking wind. Riders behind me can actually see the rear of the bike wobble. I assume the aeros of the boxes and some inherant design of the bike is the reason. Anyway after a few years i,ve gotten used to it and it adds to the character of the bike.

    But if you fix yours, tell me, I hate character. bye
    #8
  9. Solo Lobo

    Solo Lobo airhead or nothing

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    Could be the bags... but because it also happened with the stock bags, and because I know other R100GS riders that didn't have the problem with the stock bags my fingers are crossed that it's fixable... but who knows.


    I'll adjust the steering head bearing this weekend and see if there is any diff....


    #9
  10. LoFlow

    LoFlow Been here awhile

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    Yeah good point. With stock bags I didn't have any hint of a problem and with no bags also no weaving either. Also make sure that smallish front fork brace is tight. Mine had loosened up ever so slightly and I felt a small clunk when turning lock to lock in the garage. Otherwise I wouldn't have noticed it.
    #10
  11. Rubber Cow

    Rubber Cow GS Dork

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    Just curious...
    How are your swingarm bearings? When was the last time you checked 'em?
    cheers,
    Jorge
    #11
  12. Solo Lobo

    Solo Lobo airhead or nothing

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    I actually had the swing arm off about 500 miles ago and adjusted by the book then... the weaving is actually a tiny bit less noticible then last summer (with stock bags) and happens at different speeds.... I'm doing the steering head bearings today and am thinking I will also remove the LARGE spoilers from my touratech hand protectors to see if I am getting any front end weave from having those big sails out front.

    The fork brace is tight.... just checked when I put on the Acerbis baja front fender and fender brace....


    #12
  13. MotorMike

    MotorMike Adventure Dork

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    I have noticed that most bikes that you sit upright on with wide bars (dual sports with no wind shield are the worst) tend to weave at higher speeds when riding with both hands on the bars. When riding a DR350 on the freeway I always ride with one hand on the throttle, and one hand on the fork top to prevent this exact effect. It is a bit of a strange feeling to let go of one hand and have the weaving stop. Try riding with both hands on the bars, then only one hand. I bet that you will find that the slow weaving stops.

    The effect seams to be the wind pressure on one shoulder is higher than the other, that shoulder moves backward pulling the other shoulder foward, while the first shoulder starts spilling air, the process repeats.
    #13
  14. Solo Lobo

    Solo Lobo airhead or nothing

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    tried the largiader method using the section of copper pipe and I'm confused, it torquing the "lock tude" to 9ftlbs goiong to correctly adjust the "adjustment ring" to 9 ftlbs??? if so, why doesn't the torque rise significantly when you then torqu the lock to to it's final 47 ftlbs?????


    HELP!!!
    #14
  15. hogmolly

    hogmolly Dude

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    The adjuster won't turn when the spacer is removed. All three pieces (adjuster, inner lockbolt, outer locknut) get locked together by the tube. When the tube is removed, the adjuster stays put and the inner lockbolt and outer locknut wedge against the fork bridge.
    #15
  16. jtwind

    jtwind Wisconsin Airhead

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    There are usually a number of things that add up to this problem. One of the few that does it by itself is a handlebar mounted fairing or windshield and Avon Gripsters. Otherwise it's usually a combination of problemsI'd let a few pounds out of the front tire if I were you. I never see recommended pressures the same. the front is always 2-3 lbs. less. Otherwise I guess the gripsters are the problem, I've had two buddies with r100gs's and both had weaving problems with gripsters. JT
    #16
  17. Solo Lobo

    Solo Lobo airhead or nothing

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    Funny thing is I ride with a couple of fellow R100GS riders w/ Gripsters and none of them experience this problem when riding...



    #17
  18. Charles Hehl

    Charles Hehl Crazy Uncle Gringo

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    I have recent started to get the same weaving problem on my 1988 R100GS. It started when I changed from T-66's to Tourances. I can live with it now that I know it is there, but when it first happens it is a bit unnerving. :eek1
    #18
  19. crarchitect

    crarchitect Master of Disaster

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    Hey inmates, first time poster, long time lurker.

    My Jessie'd up stock windscreen wearing Fox shock'ed GS never weaves if I keep it above 100mph? What's your problem?

    But now for the question: is it my imagination, or has my steering developed a "flat spot" at 12 o'clock, straight ahead. Sometimes I feel like I have to break a spot of resistance turning through dead center. Are they shot?
    Can this be adjusted away?
    #19
  20. jtwind

    jtwind Wisconsin Airhead

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    Here is some things to check off the Airheads forum archive. JT

    I am sending this in response to your posts concerning the wobble
    problem on your 88 R100GS.

    There are many areas to look at on your bike, and the trouble may be
    caused by several working in concert to induce instability. Whenever i run
    into a problem of this subtle nature, i look to the basics first, and do some
    experiments to try to exascerbate or ameliorate the symptom by making
    adjustments at each end of any available adjustment range. I'm talking more
    about a diagnostic technique than a specific adjustment here, though,

    In more specific terms, i would look to the following: (in each case i
    mean to check that the item is not worn and is adjusted within BMW
    specification and torque or setting)

    1) Tire pressure and balance

    2) rear wheel play at rear drive (check when the rear drive is hot, rocking
    the wheel at the top and bottom, as if checking a wheel bearing)

    3)paralever bearings (i know you changed them, just re-ckeck the torque
    setting on the adjustable pin. )

    4) swingarm bearings-condition and centering as well as preload and torque on
    the locknut.

    5) engine mount bolt torque (55 ft-lb here, the factory spec is too low,
    IMHO)

    6) rear shock spring sag and compression and rebound settings (refer to the
    shock manufacturer's book for making the adjustments, or try moving each
    setting to the extreme end of its' range and test riding to feel what the
    effect of that change is. This can be very enlightening to discover what
    setting causes what symptom.

    7) fork spring condition and suitability for the loads you run.

    8) Steering head bearing setting is critical, but it sounds like you've
    addressed this. As the bearings are 14 years old now, it's time to remove,
    wash and inspect them thoroughly, then repack and readjust them. hardened
    grease can trigger the weave you're getting.

    9) check that the handlebars are centered. Don't ask.

    10) Take off the windshield. If it wasn't a pain to retype the list, I'd make
    this first on the list. Fork-mounted windscreens and high speeds don't mix.
    In avbsolute seriousness i would suggest that you never exceed 60 MPH with a
    fork-mounted windscreen fitted that's higher than your elbows and wider than
    your torso.

    This list should land you on the problem. Don't forget that eveery
    adjustment must be correct for the whole to work correctly. The GS is a
    twitchy ride in the best of scenarios, which can make it very fun to ride,
    but it is also very sensitive to little errors.

    FWIW concerning tires, i rode a 91 GS/PD today that had new Avon
    Gripsters. I only went about 5 miles, but i really flogged it through the
    twisties in my development in the way back into the shop, and I was very
    impressed with the grip, stability and lack of the roughness/noisiness that's
    evident in most tire fitments on the GS models.
    #20