990 wheel spacers issue

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by Yascher, Dec 16, 2013.

  1. Yascher

    Yascher Been here awhile

    Joined:
    Oct 8, 2009
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    394
    Location:
    Moscow, Russia
    Hi everyone.

    I was switching wheelsets over the weekend form 19/17 to 21/19 and couldn't take the front axel out from the Alpina wheel. Both Alpinas use original KTM hubs.
    Finally had to hammer it out with continuous lubrication around smaller spacer on the non ABS side.
    Looking at the parts taken out-observed that there was no corrosion, but the smaller spacer actually shrunk over the axle for some reason and left a mark.

    [​IMG]

    I couldn't put it back on the axle by hand at all, while all the surfaces seemed pretty smooth!!!

    [​IMG]

    The wider ABS side spacer had a noticeable free play in inner diameter compared to the axle outside dia. and it could completely freely slide back and forth as it should be....seems like a parts fault from KTM. Second original 21/19 wheelset had both small and big spacer of identical diameter, both could freely slide along the axle.....strange...

    [​IMG]

    when I moved to the rear wheel, same thing happened, had to hammer out the axle!!! Couldn't figure out what is wrong, but did remember that it didn't go in nicely in the first place, when I just bought the wheels from Alpina, hubs are original KTM.

    Stock wheels slide in and out freely....could it be that KTM on purpose supplied to Alpina original KTM hubs, but with incorrect parts dimentions-to make installation issues and that people would turn to buy the original KTM wheelsets instead???

    [​IMG]
    #1
  2. bikyto

    bikyto Dans le doute...gaz!

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    It could be a slight tolerance issue from factory that is affected by extreme temperatures. Kind of like bearings that you put in the freezer to shrink a tiny bit.
    #2
  3. geometrician

    geometrician let's keep going...

    Joined:
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    Those axles sure do look dry!

    You have to grease up KTM axles quite liberally, from the big Adventures right down to their little 2-strokes- I add grease when I am uncrating one from factory; just not enough there. I warn the customer when delivering the bike.

    Not sure about your spacer- the wear mark looks to be from the inside of the inner race from one of the bearings. All support/force of goes through this tiny contact patch, and w/KTM coating the axles with a protective coating this tends to get distressed/worn away & become visible. You'll probably find the mark from the other side bearing as well.

    The magnesium KTM uses for their fasteners are very soft; indeed the lips of the bearing seals themselves wear ridges into them which allows dirt & water into the gap of the inner race/axle and acts as a burnishing agent & to help stick your axle. I keep spares of my spacers on the shelf and replace them when I see the ridges forming (I do ride in mud, dirt, creeks, etc)

    KTM has poor bearing sealing which is why All Balls Racing makes "waterproof" retrofit kits for them.
    #3
  4. Yascher

    Yascher Been here awhile

    Joined:
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    Location:
    Moscow, Russia
    Thanks!

    The mark is from the spacer, not the bearing. Orhewr side is co mpletely fine.
    There was enough lubrication, as I never save on proper lubrication))) but the axle looks dry after the tight spacer was hammered out.
    Original set spacers did slide nicely around with a proper gap without any lubricant.
    I only put lubricant on the axle to protect inner bearing rings from corrosion
    All front and rear bearings look fine so far
    #4
  5. Yascher

    Yascher Been here awhile

    Joined:
    Oct 8, 2009
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    394
    Location:
    Moscow, Russia
    the difference I observed was almost 1mm, which I couldn't call tiny!!!
    Temperature is not an issue here, as all wheelsets were at the outside temperature, same as right and left spacers of the same kit....it was also my initial thought when it got stuck, but once dissasembelled it became obvious it has to do with KTM manufacturing faults
    #5
  6. bikyto

    bikyto Dans le doute...gaz!

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    You're probably right as they outsource the manufacturing of the parts to different vendors so you could have ended up with parts with different tolerances.
    #6