Reducing fork stiction - ideas?

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by uk_mouse, Jul 29, 2013.

  1. uk_mouse

    uk_mouse Aquatic adventurer

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    I've come to the conclusion that my forks are too sticky - they don't seem to react very well to small movements. And where they settle into a neutral position can be a couple of inches different depending on whether they were going from extended or compressed.

    I read about removing the third bush from the fork leg (this is a 2004 S model, so 3 bushes plus a big spacer tube), and tried this but it gave what I thought was unacceptable play in the fork sliders.

    So, are there any other ways I can address the problem? Different oil? Currently using Motul 5W oil, I have read suggestions that ATF can give less stiction. I've also got fork seal savers fitted (the neoprene tube type) which probably don't help matters.

    I'm planning a quick service on the forks this week (new oil, clean seals etc) so thought I'd ask this question before I start just in case there's anything relatively easy I can try out.

    Cheers all :)
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  2. btao

    btao RIP Lilolita

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    I use Manitou Prep M. Carryover from pedal power, but you will have zero stiction after. It's actually my go to grease for just about everything. Amazing stuff. Just apply liberally, preferably under the dust covers and then just pogo pogo pogo to work it down in there onto the bushings. Or you can take the fork apart, your choice. It's usually the seals that stick though.
    #2
  3. Hootowl

    Hootowl Long timer

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    Switching to SKF seals will help
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  4. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    Honestly you have a multitude of options, and yes the early models have horrible issues with stiction.
    I would immediately start by removing the 3rd bushing, and replacing the seals, wipers, and upper and lower bushings (can source directly through your local KTM dealer part # R14020 fork rebuild kit, you will have a few extra items as they are for the CC forks and comes with the SKF seals and much higher quality bushings)
    I would recommend going with an oil like Maxima Racing fork fluid, or something along those lines. You do not need to spend $30.00 to $45.00 a quart on super slippery, or ultra slick fork fluid.
    Having a local shop, or if you are capable of polishing the fork lowers along with doing all of the above mentioned mods will almost eliminate the stiction issues.
    Getting rid of the 3rd bushing and sleeve immediately will be the starting point. As well toss the seal savers unless you clean them religiously.


    Alex
    #4
  5. D K

    D K Been here awhile

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    Make sure they are the green ones
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  6. Hootowl

    Hootowl Long timer

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    What is the life expectancy of those compared to OEM or another mfg?
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  7. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    Depends on where you are riding and how often you clean your bike really. I have some customers in the Southwest that have well over 100 hours of hard off road use without any issues, then again I have other customers in the PNW and Canada that have gotten around 50 hours of hard off road use, the reasoning is do you ride in extremely muddy conditions or the opposite?
    The SKF seals are coming standard on most KTM models nowadays and even on the 2013 BMW F800GS as the went with the 43mm WP fork. They are the best on the market at this point and time.
    I’ve tested every seal on the market, hands down these are what you should be running, period.
    #7
  8. uk_mouse

    uk_mouse Aquatic adventurer

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    Thanks for the advice chaps.

    I have recently replaced all the fork bushes, that's when I experimented with removing the 3rd bush and spacer - as I said I felt this gave unacceptable play in the fork. It did definitely reduce the stiction though!

    But I'll try the other suggestions. I was in two minds about the seal savers anyway - do they keep the seals clean, or do they trap dirt and water?

    Question - what would you use to polish the fork sliders? Simply metal polish, maybe followed by a coat of silicon spray?
    #8
  9. DesertSurfer

    DesertSurfer Tail sprayin

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    Wow, great and timely post. Exactly what I was noticing with my 950 S forks. I've heard many guys refreshing their front suspension... I've not noticed any changes in my rear shock. Is there any periodic service required? Or do you just ride it until you blow a seal?
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  10. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    For your peace of mind, I have removed the 3rd bushing and sleeve on well over 200 sets of forks without any issue's. This was the first thing almost every enduro/desert racer did on the smaller KTM's back in the day when the forks came out. It will not create intolerable slop, it will be in line with just about every other fork on the market.
    I do not run seal savers, and we recommend against them unless you are religious about dropping them down and cleaning them otherwise mud will get packed in there and slowly destroy the seals and wipers.

    To polish the lowers heres a quick video to see how we do it: http://www.youtube.com/watch?v=Zp0u4WVX_TI
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  11. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    We recommend every 15,000 miles, or every other year as a service interval for front and rear.
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  12. uk_mouse

    uk_mouse Aquatic adventurer

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    Thanks for that. I've ordered some SKF seals, so when they arrive I'll strip the forks and experiment again with removing the 3rd bush.
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  13. DesertSurfer

    DesertSurfer Tail sprayin

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    What does a 15,000k service entail on a rear 950 Adv S shock? A drain, bushing inspection and recharge? Just asking.

    Because when it comes to suspension servicing... I don't know Jack Shock!
    #13
  14. Konflict Motorsports

    Konflict Motorsports KM TUNER

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    A shock service entails a complete tear down and inspection of all wear items (shock shaft bushing, piston bushing, oil seal, dust seal), as well as a thorough inspection of the shim stacks to see if there is any distorted shims.
    Once all items have been addressed we assemble the units without oil and use a vacuum bleeding/filling system to ensure all air is out of the shock.
    #14
  15. azcagiva

    azcagiva new orange flavor

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    Just thought that I would add, the forks will have a lot of sticktion if the front wheel is not re installed correctly in the forks.

    -John
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  16. The Griz

    The Griz Long timer

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    Do not use ATF or any non-fork oil. Your use of Motul 5w is spot on. Motul is great oil. However, if you want the fork to react faster to faster/smaller/chatter bumps then 2.5w might be in order. The lighter to oil weight the better the fork will react to fast/small/chatter movements. However, when you use lighter weight oil your low speed damping will suffer. Your fork will react to larger/slower hits slower or worse. Going to extremes on for oil weights is a 'band aid' fix for proper valving. You might need to send your forks in to get revalved.

    Do not remove any bushes, rather replace all of them. Worn bushes are one of the prime causes of stiction. Replace 'em all. Removing one of them is a 'band aid' fix for actually replacing a worn bushing.

    I have very strong opinions about the neoprene fork boots. They accumulate dirt beneath them and act like sand paper, scratching the surface of your slider tubes. I have ridden dirt bikes for years in muddy and dusty conditions both and have never used fork boots. With proper maintenance I have never had any issues.

    Switching to green SKF seals will help immensely. They will allow your slider tubes to move easier. Check out this vid:

    <iframe width="420" height="315" src="//www.youtube.com/embed/RKbV0kTVpSU" frameborder="0" allowfullscreen></iframe>

    <iframe width="420" height="315" src="//www.youtube.com/embed/FBrh-kHVbAo" frameborder="0" allowfullscreen></iframe>
    #16
  17. vwboomer

    vwboomer Buffoon

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    I would remove the extra bushings. I ripped through a fork leg on my '04 MXC300 and was confused as hell when my replacement used set had 3 bushings :lol3
    I rebuilt em the same as the original set that was mounted (but was worked by MXTech) and have not suffered any ill effects. I wouldn't hesitate to do the same on the big bike.
    #17
  18. uk_mouse

    uk_mouse Aquatic adventurer

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    Just a follow up to this topic.

    I fitted SKF green fork seals, they are expensive (£50 for a set) but worth it, as my stiction problems are now a thing of the past. I didn't remove any bushes from the fork legs, and don't feel any need to now.

    So in short, SKF seals - they really do work it seems.
    #18