Blown Fork Seals? 2001 KTM LC4

Discussion in 'Thumpers' started by dp63130, Feb 9, 2005.

  1. dp63130

    dp63130 none.

    Joined:
    Sep 25, 2003
    Oddometer:
    305
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    So this morning I went out to take the bike to work and noticed 2 identical oil spots beneath my forks. they were pretty small about 3 inches in diameter. I ran my finder down the lower fork and allot of fluid came off on my finger...

    The background is that I had trucked the bike out to an ORV about 3 hours away and my super powers may have acted up when I was tightening the front end down. I also washed with when I got home but made sure to use really low pressure...

    Did I blow my seals? The bike is a 2001 KTM six days with 320826 - TELESCOPIC FORK USD43 WP 400/640 LC4 2001

    This would be my first time replacing the seals if that is indeed what I blew?
    Thanks,
    Dan

    ** edit. found the problem. fork seal was fine just need a good cleaning. page three has a pict of it.
    #1
  2. dirtrider

    dirtrider Dusty Adventurer

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    You need to bleed your forks.

    See that little philips head screw at the top of your forks? Crack it open to let built up air pressure escape. When you tie your bike down tight or ride it hard, air pressure will build up and can create enough pressure to push oil past your seals. I recommend doing this often (I do it daily).

    Note: Do not put any pressure on the forks while bleeding them! Unless you like that oily look. :lol3
    #2
  3. Happe

    Happe Adventure Bike Spanner Man

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    Hi Dan,

    It's unfortunately a common fault on the USD fork legs. It just takes a bit of dirt and the seals start leakin. Thats one reason why most of the guys over here use this neoprene sox on the forks.

    If the seal is blown you need to replace the seals and change the fork oil.

    Just ask if you need advise for this work.

    KTM Sommer in Germany has a "quick bleed" valve for the KTM forks on offer.
    Makes the air bleeding job very fast and easy. You know you should bleed the fork every time you use the bike? :wink:

    cheers

    Stefan
    #3
  4. dp63130

    dp63130 none.

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    That seems cheaper and less time consuming than replacing the seals.
    #4
  5. Rad

    Rad Done riding

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    Use a small screw driver and get the dust seal down on each fork leg. Run a .004" -.006" feeler gauge up and around under the fork seal up inside the fork leg and clean it out real good. I have also used 35mm negative strips instead of the feeler gauge. Careful with those, they can rip. That along with the fork air bleed’n, as mention above, may just solve it for ya. If not, nut'n lost.
    #5
  6. Steelhead

    Steelhead It's all good

    Joined:
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    Yep, I learned that hard lesson about those WP forks as well.
    Since my schooling I've installed Seal Saver neo dust seals as well as a set of Motion Pro push button pressure release valves in place of the screws (mentioned by dirtrider) at the top of the fork. Had to drill and re-thread for larger diameter threads but they work great.
    #6
  7. dp63130

    dp63130 none.

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    well I'll try all avenues before replacing
    Thanks for heads up and I will now be bleeding at a regular interval.
    thanks.
    d
    #7
  8. creeper

    creeper Still alive...

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    Asside from the previously mentioned good ideas... bleeding the forks with the stock screws, or Motion Pro bleed valves, and pulling down the dust seals and using something to clean the fork seals (I like to use clean white business cards)... before reinstalling the dust seals, pack them with a waterproof grease.
    It acts as a "pre-filter" to trap the schmutz that usually sneeks past them and causes your fork seals to leak in the first place.
    Since I did it 6 months ago, my forks have not dripped a drop.

    Creep
    #8
  9. dirtrider

    dirtrider Dusty Adventurer

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    KTM sells fork bleeders in the Hard Parts catolog that fit perfect without having to drill and rethread the holes. I have them on my LC4 and EXC. I just tried to find a picture on thier website, but no luck.

    We stock them and sell the shit out of them.
    #9
  10. creeper

    creeper Still alive...

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    Yep :nod... under $20 retail as I recall. Well worth the money.

    This is more a riser shot... but you can see the valves.

    [​IMG]
    #10
  11. dp63130

    dp63130 none.

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    I see'em and will invest in them..
    What risers are those. I am in need being six foot four.
    #11
  12. Mack

    Mack Gone, but never forgotten. RIP, Mack...

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    Same here, best money spent so far, Pro-Taper Pastrana FMX bars, that and a few other mods have made it much nicer for a tall guy, no more major back aches.
    #12
  13. creeper

    creeper Still alive...

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    I made the risers myself out of spare parts but... Loadedagain is producing some very nice ones (nicer than what I coughed up :nod) for an excellent price. Shoot him a PM.
    #13
  14. dirtrider

    dirtrider Dusty Adventurer

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    Those are the ones! Part #951.016 If anybody wants a set PM me.
    #14
  15. creeper

    creeper Still alive...

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    Dirt - "bleeder valve" - rider rides (in the dirt) again... Hi Ho Adventurer...er. :D
    #15
  16. dp63130

    dp63130 none.

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    I let the air out but the seals are still leaking copious amounts of fluid... about 2 in diameter spot this morning in the garage.

    So looks like I'm doing seals.
    Any one have any advice on seals or what oil to get?
    thanks,
    d
    #16
  17. dirtrider

    dirtrider Dusty Adventurer

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    Thats "LC4 Mafia Nomad" to you pal!

    DP63130 use SAE 5 oil/ air chamber length of 150MM

    PM me your E-mail address and I'll send a PDF file on rebuilding your forks.

    Does anybody know how to attach a PDF in a reply?
    #17
  18. Rad

    Rad Done riding

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    If you also send me the PDF I will post it (Hi Creeper :lol3 ) in the hall of wisdom here.
    #18
  19. Nom de Guerre

    Nom de Guerre Long timer

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    Rad, please do post that PDF! I, for one, would love to have access to that document. BTW, has Creeper's Oil change writeup been posted in the Hall yet? I'm gonna check now, but if not... how come?
    #19
  20. dirtrider

    dirtrider Dusty Adventurer

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    What is your email address. I only know how to email it.

    Can a PDF be added to a reply?
    #20