Steering head bearings

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Geek, Apr 1, 2012.

  1. Geek

    Geek oot & aboot

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    Anyone have any tricks for getting the tension on the steering head bearings right?

    The technique I've been trying: tighten the 27 until there is tension... loosen just a tad and then tighten the horizontal clamp bolt.

    Issue is if I do it this way, I still have some slack in the stack somewhere (if can move the front wheel). Any tighter and too much resistance in rotation.

    I'm wondering if I've missed a spacer or something :patch
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  2. xdbx

    xdbx Motorcycle Connoisseur

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    You're doing it right. There should be no play at all. Try grabbing different front end components to apply the wiggle force. My guess is there's some play in something else, like a wheel bearing, or heaven forbid the brass bushings in your fresh forks. Play around. The 27 is just a tighten to remove slack part.
    #2
  3. Geek

    Geek oot & aboot

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    Thanks for the trouble shooting ideas Daniel..

    I just went out and lessened the 5 top bolts (pinch bolts on the forks and the top triple pinch.. then loosened the 27 and let everything hang loose.. tapped a bit with a mallet to make sure everything's free.

    Experimenting with just the 27... I tightened it tight.. so there is binding; around front, grip the forks right below the lower triple clamp and pull.. I have a click/clunk.

    Something's not seated somewhere in the steering head :(:
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  4. Geek

    Geek oot & aboot

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    Here's the stock diagram... it is pretty simple (and from what I remember.. this is how I did it)... anyone know of there is anything different with the Emig setup that I just installed?

    [​IMG]
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  5. Sumi

    Sumi Long timer

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    Are you sure that the #11 and #12 are seated properly?
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  6. MortimerSickle

    MortimerSickle Semi-Adventurer

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    By this do you mean you have the wheel off the ground?

    I was making that mistake, until it dawned on me that the bike needs to be sitting on the ground for the bearings to seat properly.
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  7. Sumi

    Sumi Long timer

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    Hm.. that makes sense:) I think it's time to redo mine:rofl
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  8. DeepInIt

    DeepInIt Long timer

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    No that doesn´t make sense at all. You can do the bearings with everything hanging. There are different designs but the stock KTM setup is a simple pinch between the tube end on the bottom and and the nut on the top.

    I know Geek didin´t do any of these but for the rest of the group...
    The usual mistakes are:
    1) Not loosening the other bolts. The plates of the triple actually have to become closer to each other as you tighten the 27 so I put the forks in where I want them on the top triple and tighten. Leave the bottom triple fork clamps loose and the pinch clamp loose as well. Tighten the 27.
    2) Not seating the races in the steering tube. This ruined a replacement set of bearings for me as a KTM shop set it all up and I even tightened everything after 200 miles but the minute I hit real dirt, the races seated completely and left a ton of slack in the bearings. A couple of good whacks and I had a notch in my steering again. I could not tell the races were not seated when tightening the 27, it seemed fine.

    However, neither of these explains a clunk when you have tightened down the 27 until binding (as long as the bottom triple clamps are loose). You did the correct test in the air it sounds like.

    On the ground, with the front brake actuated, rocking, is not a good test because you will always get a clunk from the front floating disk rotor. This sounds just like a bad steering head bearing. The good news is that this is twice as bad on a BMW.:clap

    So:
    Given that you are doing everything right, my vote is bad spacing as you originally said. Everything rides on the bearings. Part 11 must be there to space the bottom. I forget whether it can be installed upside down. At the top as long as the triple is resting on the spacer #6, and not the tube, you should be fine. You should be able to see this from the side even with all the crap you have on your bike. Bearing height matters for this as well.

    Also isolate the clunk. Does it still clunk if you grab low down on the upper fork tubes and pull?




    Tighten the 27. Test by turning the
    #8
  9. JOKER650

    JOKER650 Long timer

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    You are getting the clunk after you snug up the nut then tighten the pinch bolt?
    Maybe the upper clamp is not sliding on the shaft properly ?

    Edit: I just went and checked on my SE (slid the forks in the other night), Finger tightened the upper nut and no play in the head stock at all.
    #9
  10. MortimerSickle

    MortimerSickle Semi-Adventurer

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    The problem with having it hanging is that it leaves the load hanging on the top bearing. When you tighten the blind nut, both bearings are brought tight just as they would be if the wheel were resting on the ground, and that much is fine. But, when you back off the nut to release the tension, everything drops down, and any slack will be in the bottom bearing. The weight of the forks and wheel keep pressure on the top bearing and the blind nut. That makes it difficult (at least for me) to tell that the nut has been backed off only just enough. The bottom bearing might have a little too much slack, but the nut can still feel snug.

    If the wheel is sitting on the ground, the bottom bearing is loaded, and any slack will be in the top bearing, leaving the nut feeling loose, and easy to finely adjust.

    I suppose others have different methods, but wheel-on-the-ground is what works for me.
    #10
  11. RedRupert

    RedRupert Brit in the Soviet Union

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    I've always fitted new steering head bearing the Japanese way. Both Kawasaki and Yamaha say to seat the new bearings before adjusting. Yamaha (TDM 900) say torque to 52 Nm to seat, loosen completely, then adjust so no drag or free-play. Kawasaki (KLR 650) say torque to 39 Nm to seat; then adjust as Yamaha.

    To adjust KTM ADV: Before installing fork legs, cables and wires, and with the 5 x top triple clamp bolts loose, tighten the 27 so that there is a little drag; then back off until free. Install fork legs and wheel.

    With bike on centre stand, and front wheel off the ground; hold handlebar between the clamps with left hand, and grasp the front wheel at 2 o'clock and push/pull. If you feel any movement or knock with your left hand, tighten the 27 by 1/12th at a time (+ using wooden drift, tap the left and right side of the top triple clamp to relieve tension at the fork legs), until no movement or knock. When set, tighten 5 x top triple clamp bolts to 20 Nm.

    Recheck after 500 miles or so.
    #11
  12. Geek

    Geek oot & aboot

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    Thanks for the input everyone :freaky

    Dis assembly later today (ugh.. again)... I'll see what I find.

    I'm wondering that if with the emig clamps part #6 might be too tall keeping it from seating fully...
    I seem to remember a picture years ago where somebody had trimmed #6 but I don't remember why...
    #12
  13. Geek

    Geek oot & aboot

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    I found the photo I remembered

    [​IMG]
    ...but I don't think it is related. The old emig steering damper used a post that went around the head stock (mine doesnt)

    [​IMG]
    :hmmmmm


    Mine:
    [​IMG]
    [​IMG]
    #13
  14. DeepInIt

    DeepInIt Long timer

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    And that is just a dust shield.

    You should be able to feel if something is binding other than the bearing. When things are snugged and there is resistence for turning side to side, if it is the bearings, as it should be, it will be smooth. If anything else is binding, it won´t be smooth because you will be metal on metal somewhere.
    #14
  15. Geek

    Geek oot & aboot

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    It doesn't feel like anything is binding.. it feels silky smooth (like you would expect with brand new bearings).

    its the grabbing the fork tubes and feeling a click that's the issue. :scratch

    Hey.. isn't winter starting down there? Shouldn't you be migrating north sometime soon? :freaky
    #15
  16. MortimerSickle

    MortimerSickle Semi-Adventurer

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    This sounds good for the initial installation. But, I wouldn't tear it all down again for the 500 mile readjustment. So, that takes me back to the wheel-on-the-ground method.







    I'll be quiet now. :lol3


    .
    #16
  17. TheMuffinMan

    TheMuffinMan Forest Ranger Magnet

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    I had some play in mine when I re-installed. Long story short my top bearing cup wasn't seated all the way, three whacks and it was seated and my forks had zero play or notch after tightening it all up.
    #17
  18. Geek

    Geek oot & aboot

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    Got time to pull it apart this afternoon :scratch

    bottom bearing is fully seated on interference fit shaft
    [​IMG]

    bottom cup is fully seated
    [​IMG]

    top cup is fully seated
    [​IMG]

    top bearing sits nicely and rotates nicely
    [​IMG]

    space top bearing sits above steering head tube
    [​IMG]

    with triple clamp on and lower clamp fully seated...
    (i.e. I tigthened the 27mm as tight as it would go, did up the pinch bolt, and removed the 27 to see where the shaft is...)

    this is how much gap there is between the top of the shaft and the top of the triple
    [​IMG]

    Could someone who has a moment please remove their 27mm bolt and see if this is the type of gap they have? Removing the 27mm does NOT loosen your head bearings - the pinch bolt holds everything.. the 27mm is just used in tensioning.. you can remove it and re-tighten it without effecting your bike's bearings in anyway.

    :lurk

    thanks in advance.
    #18
  19. Hobbes950

    Hobbes950 Darth Kitten

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    I have about a 2mm gap. Looks like you're good.
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  20. DeepInIt

    DeepInIt Long timer

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    And you still have a click? And it clicks when you grab only the upper tubes, not the lower? Meaning, it is definitely movement in the steering head?

    The gap depends on the thickness of your top triple I think so not a great way to measure but it all looks great. But that´s using my memory.
    #20