990 sm shifting problems

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by JR_FX, Oct 28, 2012.

  1. JR_FX

    JR_FX Been here awhile

    Joined:
    Dec 20, 2007
    Oddometer:
    192
    Location:
    Funchal, Portugal
    I have a friend with a 990 SM that is complaining about the 2 gear "jumping"occasionally when he opens up the throttle or feathers the clutch to pop up whellies. Apparently, when he´s cruising everything is normal.

    What do you guys think? I´m leaning towards the gear shifting mechanism - coul be the drum with a broken wall between the tracks, or the rollers...

    Either way we are looking at spliting the cases, right?
    #1
  2. geometrician

    geometrician let's keep going...

    Joined:
    May 25, 2008
    Oddometer:
    1,037
    Location:
    West-By-God Virginia
    no you don't have to split the cases to deal with the shift mechanism

    when I am bouncing up REALLY hard-rock trails & stair steps I've had my 950AdvS jump out of gear when in 1st or 2nd into neutral- I've been riding for a long time & I know it's not my boot doing it

    I think (and have thought of starting a thread on it) that the shift-detent spring that keeps the detent roller pressing into the shift-drum gear-detent-cam is weak.

    Many bikes have had their shift detent springs strengthened by aftermarket companies like Factory-Wheelsmith Racing to keep the bike in (whatever) gear under accel/deceleration

    I've wondered if anyone (including the KTM Factory) ever produced stronger springs for this... it's annoying to be working a steep trail only to have the bike pop into neutral... :bash
    #2
  3. crashmaster

    crashmaster ow, my balls!

    Joined:
    Mar 9, 2007
    Oddometer:
    5,314
    Location:
    Alaska
    BTDT. :lol3
    #3
  4. JR_FX

    JR_FX Been here awhile

    Joined:
    Dec 20, 2007
    Oddometer:
    192
    Location:
    Funchal, Portugal
    A litle update - we opened the clucth cover and the gear shifting mechanism was all good. while at it we cleaned the clutch oil jet - it was cloged.
    The gear change got better, smoother, but the 2nd gear still pops out ocasionally.
    I´m thinking that the problem migth be a damaged shifting roller.
    Will split the cases in a nearby future.
    My questions now are:
    - what special tools do I really need do open up (and close :D) the engine?
    - besides the shifting roller(s) and the gasket set, what parts do I need (or should) order - we´re trying to minimize the inop time for the bike as it is his daily commuter?
    #4