Pinched Fork Tube

Discussion in 'The Garage' started by schultzy, Jan 31, 2013.

  1. schultzy

    schultzy Been here awhile

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    I decided to take my Forks apart this week and came across a pinched fork tube that doesnt allow me to pull the guts out. They are White Power Forks of my 98 Husaberg.
    Any ideas on how to fix the problem?
    #1
  2. ttpete

    ttpete Rectum Non Bustibus

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    Only thing I can think of is carefully cutting the tube apart with a cutoff wheel in a die grinder. The tube's junk anyway if it's crushed.
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  3. troidus

    troidus Long timer

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    You might be able to slide a pipe expander down to the pinched part and push it back out round enough to get the guts out. If it works, that keeps metal shavings from going everywhere.
    #3
  4. sledgegreen

    sledgegreen Adventurer

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    If you can heat up the outer tube, it might expand enough to release the inner?
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  5. sailah

    sailah Lampin' it

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    Is the tube actually "pinched" or are you just not able to separate the two parts? If the tube is bent or in some way deformed, start looking for a new part. If it's just not coming apart, make sure the snap ring is out, and then heat the fork tube in a specific place. Then you grab the two parts and *yank* them apart and they come right apart.

    I don't know what your forks look like but every WP fork I have ever done USD, that's how it's done.
    #5
  6. schultzy

    schultzy Been here awhile

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    You cant see it when you look at it, hopefully a shot of heat will do the trick
    A pipe expander? Whats that look like?
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  7. sailah

    sailah Lampin' it

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    Get the factory service manual for wp it explains exactly where to heat. It's not a lot of heat gently waving a propane torch from 8" away for 10 seconds kinda heat
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  8. sailah

    sailah Lampin' it

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    This is for a KTM WP48 like on the 950, but I'm sure they are close. After you heat it, you just yank the two apart. Send me your email if you want the whole manual.

    [​IMG]
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  9. schultzy

    schultzy Been here awhile

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    Sorry, What I failed to mention is that the fork pinch is one of the bolts in the triple clamp. Looks like it was over tightend and now I cant get the guts past this point out of the top of the fork.
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  10. sailah

    sailah Lampin' it

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    These are upside down forks right? So the pinch bolt deformed the outer tube? And you can unscrew the cap obviously and pull the spring etc out of the top?

    How badly is this deformed? The bushings and the critial stuff comes out the bottom for every WP fork I have ever done.

    Post up a pic, I'm confused. But based on what you have said, I'd be looking for a new fork(s) or tube
    #10
  11. mcma111

    mcma111 Long timer

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    Remove the cap at the top of the fork and unthread the cap from the damper rod. Go to the other end of the tube and pry the dust seal loose and remove the seal keeper ring. Pull the inner tube out of the outer tube. This may require a few smacks to get it apart. You should have the outer tube in one hand and the guts in the other.
    #11
  12. schultzy

    schultzy Been here awhile

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    These are not the upside down forks. I have the WP 5060 Extreme forks on it. Once I get the forks apart is there a way to fix it or do I look for a replacement. Also,

    Looking for heavier springs, any ideas where to go?
    #12
  13. sailah

    sailah Lampin' it

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    Got it. I had a set of those a year ago and sold them. They are pretty rare being used on KTMs and Bergs for only a short run. I bet Slavens has springs for those. Personally, I'd be looking for new forks, might be tough to find though.

    I think those suspension parts are so precision that when they deform in any way they need to be replaced. Does the fork cycle through the stroke find without any stiction? I'd be surprised if the fork leg is deformed in a way that WOULDN'T cause either leaking seals or stiction.

    Found this on ADV from Christian: It appears that the Berg and KTM versions were different too 300mm to 280 travel so that limits your potential candidates even more if you want to keep them stock

    And a summary of the answers:
    First, seems like KTM has changed the fork during a model year, so your bike may have something different, but as in general:
    1997-2000: WP Extreme 50mm - called 4054 - Many people really like this fork.
    17mm axle
    300mm disk
    Bracket to install a 320mm disk on these fork.
    Sommer KTM http://www.ktm-sommer.de/
    Reference 7293 if you have a 300mm disk 99 Euro
    Reference 7294 if you have a 260mm disk 79 Euro
    2001-2002: WP UpsideDown 43mm Called 4357
    20mm axle
    Disk 320mm
    2002-2003: WP Upside Down 48mm Called 4860
    20mm Axle
    Disk 320mm
    2004-2006: WP UpsideDown 48mm -- It's a 950 ADV Front end.
    26mm axle
    Double Disk Just like 950
    Axle to mount almost any wheels onto any size axle fork are made by SW mototech sold by Twisted Throttle in the USA


    As far as swapping the fork from Extreme conventional to Upside down, pretty straight forward, some welding for steering stop, read below the post from Gaspipe.

    I hope this helps others, and let me know if I need to update anything.
    Thanks all for the information.

    Christian
    #13
  14. schultzy

    schultzy Been here awhile

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    I think the pinch is in the area of the lower bolt that tightens the fork to the triple clamp. It doesnt seem to impair fork travel. I just cant get the guts out of the top when I open the fork.
    #14