Is my clutch slipping?

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by wiseblood, Nov 4, 2013.

  1. wiseblood

    wiseblood Hall Monitor

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    Hey All --

    This is regarding a 2007 950 SMR with about 13k miles.

    This morning on my commute to work, I noticed something I had never noticed before. In 6th gear, I was having some trouble rolling on. At a certain point in the throttle, opening more did not result in any power. I can't be sure the RPMs were still building, but it definitely felt odd. Like it wasn't "gripping" any more.

    Things of note: It was damn cold -- about 34F. (Engine was plenty warm, though.)

    It didn't feel like the rear was breaking loose -- no sliding sensation. Just, like the clutch was letting go.

    Any suggestions on how to confirm this is the issue, before buying all new friction plates?

    Thanks! :beer
    #1
  2. WildAnCrazymtl

    WildAnCrazymtl Political Prisonor

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    You could try loading the engine in a hill...
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  3. Questor

    Questor More Undestructable

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    I had a similar issue in September.
    Bike simply had no power. Couldn't keep highway speed on hills.

    Turned out to be a damaged diaphragm in the rear carburetor.
    Possibly damaged by ethanol.

    Check to see if the slide sin the carb snap back quickly when moved with your finger.
    If not, it could be the diaphragm.

    Let us know.
    Q~
    #3
  4. tcskibike2008

    tcskibike2008 SnowHawker

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    If your clutch was slipping your RPMs would go up but you wouldnt feel the acceleration. Sounds like its just not producing power when its cold.
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  5. wiseblood

    wiseblood Hall Monitor

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    I'm gonna try to reproduce this on my ride home. It was still dark out, so I wasn't able to apply as much mental cycles to troubleshooting (while dodging the last of the weekend drunks).
    #5
  6. ICERIDER

    ICERIDER Adventure Rider

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    I bought a used 950SE recently and one of my checks was to see if the clutch was good. It goes against the grain to do this because normally one is sympathetic on the clutch to make it last. Anyway its easy to check, even in the city in the wet. Just go up to top gear, pull the clutch, rev it, drop the clutch and it should almost instantly kill the revs down to fully engaged with power. If it does that then the clutch works and its probably something else. Not very conclusive I know, and not at max torque/power but good enough.
    #6
  7. wiseblood

    wiseblood Hall Monitor

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    Thanks! :beer

    I did this a couple times this morning. About 30-40 mph... up to 6th gear... pull in the clutch, then let it out. The engine bogged immediately.

    Based on that, it seems like maybe my issue is something else. Still kinda unsettling. I'm not used to having a "flat spot." So far, it only happens at about 80 mph in 6th gear when rolling on.
    #7
  8. ICERIDER

    ICERIDER Adventure Rider

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    Aha! It sound like we're into the realms of carburation. My 950's do this exact same thing and I put it down to a weak mixture. Just make sure you have no air leaks or vacuum leaks and the tank vent is working.

    Above that it means removing the tank, checking float levels, checking diaphrams etc as advised, perhaps raising the needle 1 clip. If you're not into all that just ride around it. Probably showing up more now the temps are dropping.
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  9. wiseblood

    wiseblood Hall Monitor

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    Humm... Maybe. Just didn't feel right to me. Power just ended. It didn't fade... it felt like it just broke loose.

    I did service the carbs at the end of April, and they looked OK. Also, did my 9500 mile maintenance which included inspecting for leaks, just three months ago. Maybe I'll give 'em another look.
    #9
  10. Gustavo.Ramos

    Gustavo.Ramos Long timer

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    to rule out the clutch issue i'd go to a steep hil and in 6th gear perform a few roll ons accelerations loading the engine. If it slips you'll know right there, revs will skyrocket after a certain point! If nothing wrong and unprepared, you+bike might take off, so be carefull!

    If not, still flat spot, than there's something related to air/fueling.

    Try this, in 80mph in 6th when you feel the flat spot, pull the choke lever. if the flat spot disappeards then you've got a air problem (the bike, not you!) probably a leak, of bad diaphragm in one carb.
    #10
  11. Questor

    Questor More Undestructable

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    Still thinking the diaphragm may have problems and the slide is not working as well as it should.

    Your symptoms sounds exactly like what I was experiencing.

    On either end of the carburetor there is a black plastic dome.
    [​IMG]

    In that dome is a spring and a rubber diaphragm.
    The rubber diaphragm can get torn or have splits in it.

    KTM part:
    Vacuum Piston Cpl
    60031035000

    The bike will be normal most of the time, till you need the power and then it will just feel flat. Like you're "missing" power.
    Like going up a hill in 6th gear on the highway, and you just don't have all the power you are used to.

    The rubber diaphragm is not hard to get to. I'd check that.
    Open up the air box.
    Pull off the cones.
    Use your finger to push the slides back.
    They should slide back slowly.
    If one slides closed slowly, that would be an indicator of a torn diaphragm.

    This just happened to me last month.

    Let us know what you find.
    Q~
    #11