800GS shock bolt design flaw?

Discussion in 'Parallel Universe' started by johngil, Jul 16, 2009.

  1. Dolly Sod

    Dolly Sod I want to do right, but not right now

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    These are indications that these riders possibly spend more time with the bike on it's side than on it's wheels. When the bike is on it's side there's very little stress placed on the shock or it's mounting points.:evil
    #41
  2. johngil

    johngil Reseda, CA

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    Agreed. But I did ask you a question.
    I'm willing to be one of a few and possibly totally screwed here if that's the reality.

    The design puts more emphasis into mounting the seat lock than being a strong, triangulated shock mounting point.

    Since this is the internet, I will go out of my way to tell you, Joel, that I'm not trying to start any arguments or question your experiences. I'm just sharing mine.

    See you on the trail! (if I ever get my bike back)
    #42
  3. Bruno T .

    Bruno T . N8YQ

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    If that were the case you would find bent bolts, mounting ears and possibly frames.

    When a shock is bottomed hard, with enough force, something will bend/break. That's the case on any motorcycle. The question is how much force does it take to bend/break things, and what things bend/break.

    Nothing is indestructible.
    #43
  4. itsatdm

    itsatdm Long timer

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    I hope it works out for you. IMO that cross tube can't be straigtened, it will only bend again, but it can be replaced. As to the bolt and bushing, it appears a larger diameter bolt could be made to fit with some drilling and tapping or a 1 piece bushing used for both the shock and rubber mount. Hope it doesn't come to that, but better than nothing.
    #44
  5. johngil

    johngil Reseda, CA

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    You are correct that the cross tube can't be straightened in my opinion. As for replacing it, I don't know. It's pretty much socked in.
    I have some ideas if I'm forced to repair this myself. I just don't want to go there. I'm an electrician, not a bike builder. I will use my insurance if need be. I couldn't sell the bike w/ any home made repair job w/o full disclosure.

    signed, disappointed:cry
    #45
  6. AKTroy

    AKTroy BE AWARE OF TRAINS

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    Good luck with this and good for you for that kind of stand up character.
    #46
  7. johngil

    johngil Reseda, CA

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    "My guess is not worth that much since I have not had my own hands and eyes on your bike but for the little it is worth, I think that a part was defective or the mount bolt was left too loose and one or more parts of the frame bent and or the spacers were deformed. Once this happened no amount of replacing the bolt will do any good because quite honestly the bolt is not there to resist flexing, it is there to apply tension and the spacers and frame carry all of the sheer and flex load."


    I think this sums it up.
    #47
  8. johngil

    johngil Reseda, CA

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    That's your wife's job.
    #48
  9. Bruno T .

    Bruno T . N8YQ

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    I'm with John on the weak mount design theory. I'm no engineer, so i'm far from having any hard data to confirm my suspicion, but the span just looks too great to offer enough strength to the mount.

    I also opine that the split (wimpy) bushing in the Ohlins shock exacerbates the tendency for the bolt to bend. If the bushing were stronger, it would aid in keeping the bolt from flexing.

    EDIT - It would be interesting to me if someone could do some stress analysis on that bolt/mount. How much force does it take to bend the bolt and ears in the mounting configuration of the 800 GS ? Is it an acceptable figure ?
    #49
  10. johngil

    johngil Reseda, CA

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    I think I will contact my Ohlins rep. on this situation as well.
    #50
  11. Bruno T .

    Bruno T . N8YQ

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    I recommend you speak with Matt Sage directly, at Ohlins USA.
    #51
  12. CrazyMike

    CrazyMike ***42***

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    Matt's work number is:
    828-692-4525 x308
    #52
  13. johngil

    johngil Reseda, CA

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    I have previously dealt w/ Jerry.
    I will keep this # as well.
    #53
  14. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    John, I just checked mine, well at least I eyeballed it. Its straight. To my eye anyway.
    #54
  15. johngil

    johngil Reseda, CA

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    Do you have any photos of the top shock area of your aftermarket shock?
    I'm interested in something Bruno T mentioned about the Ohlins spacer/bushings.
    #55
  16. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    Ill tell ya what, since your a good guy, Ill go down and take off the cover again and take one.
    Standby.........
    #56
  17. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    John,
    This is the HyperPro shock. Does this shed any light for you ?
    :dunno
    [​IMG]
    [​IMG]
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    [​IMG]
    #57
  18. johngil

    johngil Reseda, CA

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    Is there a heim joint or some sort of swivel bushing on the shock mounts?
    I'll post a couple of photos of the Ohlins setup later.
    #58
  19. kmueller_gs12

    kmueller_gs12 Adventurer

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    @dockinpilot
    hi my name is klaus from germany.
    my daughter ride a 2008 f658gs original sock lowered.
    this week i change the shock to an normal high wilbers shock.
    in the reprom bmw wrote tighten the bolts with 100nm.
    the bold at the swingarm is ok, but at the upper bold i cant tighten to 100nm. i can turn it further.
    how do you did it when you change the shock
    sorry for my english.
    thanks and best regards

    klaus müller
    #59
  20. DockingPilot

    DockingPilot Hooked Up and Hard Over

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    John, well, it's a one solid piece bushing if thats what you mean. ?
    #60