Ktm 640 front wheel bearings

Discussion in 'Thumpers' started by wayne640, Aug 10, 2007.

  1. wayne640

    wayne640 the twin can man

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    Any body have any tips on removing the front wheel bearing from a ktm 640 04 model, now ive never had problems before but stuffed if i can work out how to remove these ones.
    As the internal size of the bearing is the same size as the spacer shaft inside the hub, leaving no area to get a punch or such to knock them out.

    Any help would be appreciated, and yes i checked the thread index to no avail.

    cheers
    #1
  2. Dotbond

    Dotbond Africa, Africa

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    Good question.

    :ear
    #2
  3. meat popsicle

    meat popsicle Ignostic

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    Paging Loadedagain. Loaded to the White Courtesy Phone... :loaded
    #3
  4. Loadedagain

    Loadedagain making chips

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    wish i could help mate, but i've never done a set of the newer ones.

    if the bearing is the same size as the spacer (which is doubtful as then there would be too little clearance to insert the axle easily, and the spacer would turn in the hub) use a very sharp punch from opposing side and do your best to get it to hook on the bearing edge.
    #4
  5. sherpa

    sherpa ...Robert

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    While I've never done my 640 bearings I've seen the same thing you describe on other bikes.

    The spacer floats in there and needs to be moved to the side inorder to get a purchase on the bearing race. Take a long rod and insert it in the wheel to the opposite end of the spacer and pry it over. This can require quite a bit of force especially on my Husky's rear wheel which calls for 142nm of torque when tightening the axle. This tends to really bind the spacer even when the wheel has been removed.

    Hope that helps...let us know if the 640 is as I describe...:ear
    #5
  6. meat popsicle

    meat popsicle Ignostic

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    damn. is there a special tool listed in the service manual? maybe a pic of that tool would help you understand how to do it?
    #6
  7. crazybrit

    crazybrit Long timer

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    Buy a pitposse bearing remover. I long ago gave up on using punches and drifts or worse, screwdrivers. Why risk damage to your hub?

    The PitPosse is the best $40 I've spent. I've used it on like 5 bikes now and friends use it all the time also.

    Also, don't beat on your sockets to reinstall, cut the old outer race off using a dremel or hacksaw, use this to reinstall and you can use channel-locks to pop the race driver out should it get stuck in the bore (the cut you put into it allows this).
    #7
  8. dirty_sanchez

    dirty_sanchez Dirty_Sanchez

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    The bearing is mounted and fixed using a shrink fit.

    I'd contact a KTM guru/factory mechanic/or otherwise wise old sot to discover how hot the hub must be heated to in order to expand enough to allow the bearings to either be tapped out or drop out all by themselves.

    I wouldn't use a blow torch here, but would more likely use a heat gun along with some sort of temperature gun.

    Years back I mounted loads of bearings this way on Vespa engines.

    Dirty
    #8
  9. bigborefan

    bigborefan Making new friends

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    I concur on the PitPosse kit. I bought one myself, works great on my Jap bikes. However, there is not a big enough driver for my KTM 300XC. Are the bearings smaller on the 640? Jusy my 2 cents worht.
    #9
  10. crazybrit

    crazybrit Long timer

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    Good point. I've not done my 950 yet and IIRC it's 30mm. The 640 got the 950 fe in 2005 IIRC. Not sure what a 2004 is. What are the other front axle sizes, 26mm (recent) and 20mm (older).

    There is a 20mm and a 25mm in the PitPosse kit, I've no clue if the 25mm fits, probably not.

    Ugh.
    #10
  11. wayne640

    wayne640 the twin can man

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    Thanks for all the info, heres how its done.

    Loaded was correct in his statement..........There is a spacer colar inside the hub and the bearings sit hard up against it either end.

    This inside collar at first appear to have no movement, but after a few light taps with a punch. It moves just enough to expose a small amount of lip on the inner bearing race.

    The only way i could get the first one out, was to put a long punch through the hub and work my way around the bearing moving the spacer collar each time to expose the bearing lip.

    Once the first one is out the spacer tube slides out of the hub and the other side is easy, just a socket on a extension bar and few taps it was out.

    After i finally removed the first bearing and the collar tube,the amount of movement it has inside the hub would only be in the thous.The slightest amount of dirt /grease is enough to lock it in, as it was in my case.

    But a word of WARNING that tube is made off very soft alloy and marks very easily, wouldnt take much at all to damage the end of it. Trying to knock it out the way so you can get to the bearings.Then that would cause the axle spacer not to sit in the hub properly when you put the wheel back on the bike.

    cheers wayne
    #11
  12. Queen of Spades

    Queen of Spades tall drink of water

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    #12
  13. Beezer

    Beezer Long timer

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    I weld an old bolt or a big washer or whatever I have across the race... now ya got something to hit & it'll drive right out.... especially if you go after it right away before things cool off. some bearings will even fall right out after the weld cools a bit because it shrinks
    #13
  14. zach613

    zach613 n00b

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    If they are like every other dirt bike out their and are a press fit, take a map gas torch and heat the hub a little and then flip the rim over and tap that side against somthing solid. it should drop out or close to it.
    #14
  15. bmwktmbill

    bmwktmbill Traveler

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    That works and you can sharpen a long round steel rod and work through the wheel axle hole on the bearing on the opposite side after heating with propane or a heat gun.

    Why are you changing them, if they are not bad just do the seals and pop off the side shields on the bearing with a knife point, wipe in some fresh grease with your finger and reinstall the side shield, replace the seal.

    I have left the seal in place, reached around it to pop the shield, wiped in fresh grease, replaced side shield, go.

    Clean any gunk off the axle and clean the axle clamp areas well.

    Reinstall the wheel according to the owner's manual sequence.

    bill
    #15