Front End Wobble R100

Discussion in 'Airheads' started by spcyrfc, Jul 9, 2012.

  1. spcyrfc

    spcyrfc Adventurer

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    I've got an R100RT (naked). I just recently installed a Reynolds rack and luggage mounts with i believe BMW touring bags (they say BMW in big letters on the side and have no roundel).

    Riding for the first time with the bags i'm noticing i heavy low speed shake when I take one hand off the handle bars. At higher speeds the shake shows itself at times, but not always.

    Could this be a problem with the frontend? backend? or my install?

    Thanks for any help.

    Luke
    #1
  2. patanga

    patanga Been here awhile

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    My money would be on the steering head bearings. Have you checked their adjustment? Only slightly loose will give you that symptom.. Check also for any notchiness in the steering centre position. If you're unsure, take it to your local BM specialist or tech guru for a second opinion. Cheers & good luck.

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    #2
  3. shearboy2004

    shearboy2004 KIWIINUSA Supporter

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    My money would also be on the steering head bearings , that said I recently purchased an R100GS 88 model and I thought it wanted to kill me as I rode it back from OK to CO , it was all over the bloody place and going past trucks was downright terrifying!!

    I had a good look over it when I got home and noticed the preload on the rear shock was done up really tight , I backed it off and adjusted the sag and now it rides as straight and true as an arrow . I love it :freaky
    #3
  4. spcyrfc

    spcyrfc Adventurer

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    Thanks guys. Will check out those two things and report back.
    #4
  5. boxerboy81

    boxerboy81 Stay Horizontal

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    Check tyre pressures too. fr 34-36, r 36-38...
    #5
  6. bikerfish

    bikerfish flyfishandride

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    I've had various beemers do this on occasion. good advice so far, steering head bearings, rear shock condition and preload setting, tire pressure, even a combination of the above. try to get everything checked out and adjusted properly and see what happens.
    #6
  7. patanga

    patanga Been here awhile

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    Was it a high front guard type?.. I experienced a similar symptom at highway speeds with an early high guard R100GS. I found that the nose of the guard was bending over at higher speeds acting like a rudder and causing the bike to go into a slow weave as the guard would flip one way and then the other. I guess that might explain why BMW put the heavier/ stiffer nose tip on to later models.

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    "The only reason people get lost in thought is because it's unfamiliar territory" (Joe Garcia)

    Check us out on facebook at "BMW Airheads Downunder", (The Australia and New Zealand Airhead Community). "B.A.D" :wink:
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    #7
  8. carpetburn

    carpetburn Been here awhile

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    Is your front tyre a bridgestone BT45?
    #8
  9. spcyrfc

    spcyrfc Adventurer

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    Front tire is a dunlop 404. it's old and i'm about to replace it. Replacing the back sometime this week with a michelin activ and will probably do the front as time and $ allow.
    #9
  10. DaveBall

    DaveBall Long timer

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    Start off with the simple and easy stuff. Not necessarily in order listed.
    1. Tire pressures - I run 34 Front and 38 Rear.
    2. Check rear shock settings. You might want a little stiffer now that you have added extra weight.
    3. Check the Steering head bearings. Easy to do. With bike on centre stand and front wheel in the air, Centre the bars and with the slightest pressure, on one side or the other, they should smoothly swing in the direction of the pressure. You should also be able to feel if their is a centre notch. Before replacing the bearings, try pulling the stem apart and cleaning out all the old grease and replacing with a good quality and re-install. Then adjust properly. I find this fixes a lot of issues, and saves a few $$
    4. Replace both front and rear tires and have them high speed balanced. I always run a matched set of tires. i.e. same brand and matching front to rear construction and treads.

    Oh, and if you are running a top box (trunk) then all bets are off. I find that a trunk will grab more air and cause handling to go to shite. Throws the balance all out of whack.
    #10
  11. carpetburn

    carpetburn Been here awhile

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    I chased a wobble in the front for a long time, tyre pressures, steering head bearings and everything else i could think of, pilot activs fixed it all when replacing BT45s, i cant coment on the 404 but is the front tread wearing in blocks/steps?
    #11
  12. spcyrfc

    spcyrfc Adventurer

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    front tread looks to wear pretty even, but i'm not sure i'd know what blocks/steps would look like. I'll do some looking. spending some time with the bike tomorrow. rain has kept me away.
    #12
  13. carpetburn

    carpetburn Been here awhile

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    With mine and many others ive spoken with BT45 fronts- the tire has a staight line/groove in the middle and the tread blocks run off it, the tread wears high and low in steps that cause the handlebars to shake from side to side at lower speeds[definately no one handed riding], it is how that tyre wears[bad imo], I cant comment on the dunlops. I only mention this as it caused me many head aches trying to sort and you wouldnt think the problem would be from a half worn tyre. The pilot activs fixed what all the other adjustments couldnt for me. Just my 2c
    #13
  14. DaveBall

    DaveBall Long timer

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    I have run the BT45s and did not experience that issue, but that was a few years ago, and maybe the compound has changed. I now run the Bridgestone Spitfires on my RT and am very happy with them. On my 3rd set. No issues at all and work well for my style of riding. Plus, they are a little bit cheaper, so more gas for the tank.
    #14
  15. spcyrfc

    spcyrfc Adventurer

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    I changed the rear tire and stiffened up the rear shock (thanks to a friend for his help) and checked the steering head bearings for play, but did not inspect them as there was no play...

    The wobble is STILL there, albiet a little better now.

    My next two steps:

    Tomorrow i will ride without the bags attached to the rack and see how it goes

    Next week I will order a matching new front tire. I can really tell a difference with the new activ on the rear.

    thanks all for the input and advice.
    #15
  16. DaveBall

    DaveBall Long timer

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    When you said you checked the head bearings and found no play, did you find any notchiness. i.e. with front wheel off the ground, turn the handlebars very lightly from side to side. They should move very smoothly and not seem to catch or want to stop, until they get to the end of travel in either direction. Quite often you will find a bit of notchiness with the bars pointing straight ahead. If you even have a little there, it is time to pull the bearings and clean them and re-grease. Then setup the bearing preload correctly. If there is old grease in there that is starting to harden up, you have to get rid of it.
    #16
  17. ME 109

    ME 109 Long timer

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    I wouldn't expect the bags to make any difference at low speeds, say up to 40 mph.
    A new tyre on the back often cures a twitchy front at higher speeds so the back tyre wasn't the problem...

    How true is the front wheel? A bent wheel could cause problems too.
    And then of course there is the 'ol fork alignment to consider.
    #17
  18. milo

    milo Long timer

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    My experience with this is the worn front tire may be the main culprit. A slightly too loose steering head bearing along with a worn front tire will be even worse. When I installed new tires it mostly went away but I could still feel a bit of something. The steering bearing had no noticeable play or movement but I snugged it up just slightly. This time it tracked like it was on rails around that down hill sweeper at 75 mph.
    #18