2012 KTM 690 death wobble

Discussion in 'Thumpers' started by SnaDank, Oct 31, 2013.

  1. SnaDank

    SnaDank Adventurer

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    Hello Everyone

    I have a new bike & have a Dunlop 606 on front
    Mefo (New) in Rear Air pressure 25/25
    I have gotten the mad wobble from day 1.

    When I put my tools/gas (Mohove bag) or Camping Giant loop Coyote bag
    Not as bad.

    Just had bike lowered with the link 1 5/8 & raised front back up a scoosh (a tad)
    NO CHANGE, mabey a little worse

    Please help, I dont want to buy a $400 steering dampner

    Dan
    #1
  2. joexr

    joexr Banned

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    If you're saying you lowered the front also , then raise it a little at a time until the wobble gets better. Tilting the bike to the rear increases the steering head angle providing stability. Decreasing rake improves turning at the expense of stability. You may have a taller rear tire and/or a lower profile front tire than before.
    #2
  3. SnaDank

    SnaDank Adventurer

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    Thanks for the reply,
    I had the bike lowered front/back 1 5/8 THEN brought front up
    1/2 inch
    #3
  4. CanadianX

    CanadianX Oh!? That is deep.

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    Search an ye shall receive...or something like that. Should be easy to find threads on this issue. Here's a non-tech synopsis of the common thoughts on this issue. 1. Front/rear geometry is off I think the thought is that the backend is too high?? So the fix is to adjust and set your sag then maybe dial it down just a hair. 2. Could be the front and rear suspension settings are not balanced...play with settings?? 3. Could be wheel balance and air pressure.

    Most common seems to be 1. My experience is that with a new tire (rear) I get a wobble at about 120km/h once it is half worn, as it is now, I loose the wobble and can rip along at 150+ So I tend to think the back end needs to come down a bit and did take a bit of preload out which helped, so maybe another 1/2 to 3/4 turn will resolve the issue. I've been told that adjusting the rear spring shouldn't be done while it is on the bike as there is a lot of tension on the thread and rings. I make small adjustments and ensure it is clean and then add lube to help the ring turn. I use an drift and tap it around ...very gentle like. Hope that helps some.

    Found these links for you to read up on:
    http://www.advrider.com/forums/showthread.php?t=811593
    http://www.horizonsunlimited.com/hubb/ktm-tech/690-enduro-handlebar-wobble-52049
    #4
  5. OhBoy

    OhBoy Got Out

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    OEM MT21s, showroom floor set up, yielded a wobble at 65+mph.
    Being a being of limited inseam I lowered the rear by adjusting the rear spring.

    Wobble gone... and fewer low speed bike drops.

    As they say...lots of threads on this issue.
    #5
  6. SnaDank

    SnaDank Adventurer

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    Thanks guys.. Appreciate all ur help.
    #6
  7. Bill the Bong

    Bill the Bong Supern00ba

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    Although my suspension was not lowered, I also had the same issue. Realistically, it was best with a Mich T63 front and Desert Race rear. Mine would shake even with a steering damper. Any other tyre combo I tried, resulted in head shake.
    #7
  8. ktmmitch

    ktmmitch Been here awhile

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    Try running static sag about 10/20mm to keep rear firmer.
    #8
  9. monkone

    monkone n00b

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    Tried all the fixes, lowered front forks, adjusted sag , balanced front wheel and played with clickers. In the end I put my super enduro front fender on and the poblem was finally resolved.
    #9
  10. 2 SPOT

    2 SPOT wannabe

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    when you say lowered forks you mean raised the front end up right?

    i have heard of fenders doing odd things, doesnt surprise me.
    #10
  11. mtntrails

    mtntrails Life is Short...

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    Aside from "death wobbles" and "tank slappers" which can be extremely dangerous, there are plenty of other benefits to having a steering damper - well worth the $.
    #11
  12. Pantah

    Pantah PJ Fan from Boston

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    Thanks Bill - Just so happens I have a new Desert Race and T63 to mount. I don't have a wobble, though. Mine is lowered on inch with the front fully extended. I have a damper, that helps with the shoulder buffeting above 70 mph. I was hoping the T63 would be quiet like it is on my Yam.

    I had a 950 that had a wobble when decelerating loaded. I tightened up the pre-load and damping at both ends and it never wobbled after that.
    #12
  13. SnaDank

    SnaDank Adventurer

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    Monkone, do you have a photo of your supermoto fender?

    So if i put a 990 type fender on it will get rid of my shake

    Dan
    #13
  14. DuctTape

    DuctTape Been here awhile

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    Other then the cost I really don't understand the aversion to steering dampers people have?

    A lot of riders in the Orange Crush Forum call it a bandaid for an otherwise serious problem even when I point out that Superbikes like my Ducati 1198S and Aprilia RSV4 come from the Factory with Ohlins steering dampers on them and they are ridden on pavement only?

    Anyway I put a Scotts on both my 690 and 990 when the bikes were first brought home and they have never had a wobble no matter the tire, speed or terrain.
    #14
  15. 2 SPOT

    2 SPOT wannabe

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    i DONT have a damper and have never had wobble no matter the tire, speed or terrain, so now what do we do?

    for me its not an aversion to a damper, i havent felt that i NEED one yet, maybe i'm not riding hard enough? or maybe i have adequate upper body strength?
    i dunno, but in any event, dampers are a performance riding aid, not a mask for underlying problems.
    #15
  16. Pantah

    Pantah PJ Fan from Boston

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    Maybe somebody who knows more can chime it. I am pretty sure there are two types of steering dampers. Roadracing dampers damp in both directions, while dirt dampers damp only in one direction.

    Roadracers require dampers to control headshake, typically induced under power when transitioning through an esses. Poorly suspended road racers can morph into an uncontrollable tank slapper under power upon exiting a turn, which the damper can help contain if it's not too violent.

    Dirt dampers contain wheel deflections caused by the terrain.

    I use a steering damper on my 690, but I use only a modest amount of damping and it is to assist me in reducing high speed wobbles on the highway induced by turbulence. I found that some DOT knobby tires are more likely to wobble than others. A TKC80 for example.

    When I first installed the damper I took it out on the freeway and cranked up the damping to stop the wobble over 70mph. Then traffic came to a stop, and I nearly crashed the bike because the damping was too stiff to counter steer at low speeds. :eek1 It took awhile to figure the damper out, and it varies by the conditions.
    #16
  17. Velociraptor

    Velociraptor TrackBum

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    I have a damper on my 690. The main benefit is minimizing deflections off rocks off road. Of course we all try to avoid hitting those rocks, but not always possible. Having a damper can mean the difference between the front wheel getting deflected so bad it causes a crash, and ......not.

    I run a damper on all my bikes. Saved me one time during a track day on a GSXR-1000. I stupidly took the wrong line through a high speed corner and hit a big bump at full lean at about 90 mph. The bike got really out of shape but recovered. Without the damper I would have crashed for sure.
    #17
  18. Bill the Bong

    Bill the Bong Supern00ba

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    I fitted a damper to the 690 to cure the wobble thing, but it did not. The oscillations are small enough that its inside the dampers reaction area, so to speak. However, on a recent rally we had about 100km / 60 miles of mud during a liaison. I had rally style tyres - large, short knobs - on and I was scared shitless. 3 times I lost the rear at high speed in particular treacherous patches. Every time the damper straightened the bike without drama after I have already picked my crash site. I'm amazed and converted.
    #18
  19. NovaMoto

    NovaMoto Been here awhile

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    It's the tires. I put a set of 50/50 Heidenau's on mine and I can cruise at 140kph all day. With the MT21's or Motoz 110kph is pushing it in terms of stability.

    My 0.02 :)
    #19
  20. Pantah

    Pantah PJ Fan from Boston

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    Yes, the tires make a difference in high speed wobbles. Mefo, Pirelli and Heidenau dual sport tires are triangular and track better on the pavement. Most DOT knobbies have a round cross section and are definitely less stable over 90mph. :eek1
    #20