Clutch master cylinder leaking

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by booger1, Jan 15, 2012.

  1. booger1

    booger1 Been here awhile

    Joined:
    Mar 10, 2010
    Oddometer:
    960
    Location:
    Arizona
    Just got back, had to cut the trip a little short do to the clutch master cylinder leaking and starting to loose tension.
    I've read a few posts on this issue, but there dated abit. Has there been any improvments, cures, or best replacment options?
    #1
  2. DeeGee

    DeeGee I'm a Yorkshireman thanoz

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    There's an overhaul kit you can buy. I've had two go on me, one in the Czech Republic on the old 950 I had stolen :cry and once on my current ride. Cost me around £35 for the O ring, spring and little piston/plunger.

    I bought it from a KTM dealers so you should be able to source one. I did post up some pics of it at the time. I'll see if I can find them.
    #2
  3. booger1

    booger1 Been here awhile

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    Everything that I've read, seams that rebuilds don't last very long.
    I'm looking for a long term fix. I've seen some expensive mc's, but if it's a long term fix I'm willing to do that.
    #3
  4. Dale950

    Dale950 Been here awhile

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    Melb / Australia
    Yes Ive had the same problem over the years , put 2 or three kits through mine , at present it seems to have settled , but the next step is a new master or get the bore re sleeved in Stainless , problem seems to be the alloy bore wears .

    Check out this Co that does it .
    http://www.resleeve.com/sleeving.htm
    #4
  5. booger1

    booger1 Been here awhile

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    Thanks Dale. I'll try and get a hold of them this week.
    #5
  6. Dustodust

    Dustodust Long timer

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    Hillsboro Oregon
    any master and lever that has the same size oil bolt would work
    like maybe a Nissin off of a CRF 450 is where I'll be headed when mine blows
    #6
  7. AdvGa

    AdvGa Long timer

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    #7
  8. Navin

    Navin Long timer

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    The 9.0 Magura clutch master is what you want. Under $200, shop around. Cuts pull by about 40%. Awesome mod nobody does. :lol3
    #8
  9. dmn0507

    dmn0507 Been here awhile

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    Mine was pretty worn out after 64K km and it was leaking (it started leaking a bit at 25K, but some fresh oil every 8-10K was enough to fix it) and since i'm cheap i've re-sleeved it (a friend did that for me) with a brass sleeve and its like new.
    The piston is still the original one.
    #9
  10. rider914

    rider914 Agnostic Adventurer

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    Stock master cyl on the adventure (not sure about other LC8s) has a large offset from the bars to clear the left side switch pod. Very different from the one on my 525 (also Magura) which is much closer to the bar. Not sure about the Nissin or others, but something to watch for.

    -M
    #10
  11. booger1

    booger1 Been here awhile

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    960
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    I contacted resleeve.com. Seems good enough for me, $120 plus shipping and I supply a rebuild kit.
    I think thats the best way to go so that I can retain original parts and make it more durable with the stainless steel sleeve.
    I contacted a local machine shop here in town and they want 3 hours min at $85 an hour, so very resonable. Let you all know how it works out when it's all said and done.
    Thanks for all the suggestions.
    #11
  12. Quietus

    Quietus Mariner

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    Oddometer:
    477
    Location:
    N.Smirni - Athens - Greece
    I have the same problem for a few days now. I've talked with my mechanic and he told me that it's a common problem since KTM upgraded the slave cylinder - or on bikes that put evoluzione/oberon/etc. Since the slave is more robust the master gets worn quite easy. The rebuilt kits don't work cause the problem is in the housing of the piston and not on the piston or the sealings, so even if you rebuilt it, after some time it's gonna start leaking again. He suggested not to put another magura or another 10.5mm master cylinder because it's goint to happen again. Seems that the best option with no future problems will be a radial one from super duke that it's 16mm. I found one used for $150 and bought it. I'll install it by the end of next week and I'll post an update.

    Cheers
    #12
  13. Navin

    Navin Long timer

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    Sicass Racing switch solves that. My 9.0 has been dandy up against a Evo slave. The SD had a super stiff pull, I'd avoid that.
    #13
  14. booger1

    booger1 Been here awhile

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    Have you installed this yet???
    Just got word back from resleeve.com that they will not be able to do this. There web site says 1/4 in and up but they say they can't so there sending it back to me today.
    i guess I'll just put the rebuild kit in for now, but still want a better fix.
    #14
  15. rsuncloud

    rsuncloud Adventurer

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    Do you or your friend have any pictures? I think I know what you mean but a picture is worth..... Saw a link for someone from uplan ca using stainless sleeve??
    #15
  16. booger1

    booger1 Been here awhile

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    For now I ordered a new MS and will look into this further when I have time, for right now I jsut want to ride. I contacted some one else in northern Ca. He asked for some pics before sending it to him, but I have to wait for the old to get back to me before doing this.
    #16
  17. dmn0507

    dmn0507 Been here awhile

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    No pics sorry, anyways the brass sleeve has about 3mm thick wall (internal diameter just a little over the piston diameter).
    No need to reach the bottom of the MC with the new sleeve, 4-5 mm from the bottom is ok, that's the space where only the piston spring goes, so even if the sleeve isnt perfectly aligned with the old hole is not a big deal.
    #17
  18. gefr

    gefr Life is a trip

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    just where the liquid store feeds new liquid into the system? What dia hole did you drill to fit the sleeve in? Where did you find such a smooth pipe?
    #18
  19. dmn0507

    dmn0507 Been here awhile

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    Right! i've forgot about that :)
    The brass sleeve was obviously machined by my friend, dont know exactly the external diameter of the sleeve, but roughly it was 15mm, i would say "the thinner, the better" (so u dont need to drill out a lot of your m/c) as long as its strong enough to be slightly (almost nothing) pressed in, we used some loctite to avoid any leak.

    I drilled the hole (actually 2) for the reservoir, the big one is 2mm IIRC, the tiny one is about 0.5mm and its in front of the other hole, under the little metal screen (this is the self-purge hole), i've used a .7mm because it was the thinnest available. After drilling i've smoothed the inside of the sleeve with some fine sandpaper (just where the holes are).
    Holes drilled AFTER installing the sleeve, of course.
    #19
  20. Quietus

    Quietus Mariner

    Joined:
    Oct 7, 2007
    Oddometer:
    477
    Location:
    N.Smirni - Athens - Greece
    SD's master cylinder installed. I had to buy an adapter for the tube to be able to fit as it has smaller diameter but nothing else. Just installed it, bleed it and ready to go. It's somehow stiffer than the original but not that much that it can be a problem even when I drive downtown during rush hour.

    Cheers.
    #20