Head stem bearing?

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by COXR650L, Jan 12, 2018.

  1. COXR650L

    COXR650L Long timer

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    I'm doing a full tear down on my 950. I pulled the head stem and there is plenty of grease, however the lower bearing has demples on the front and back of the race. They are very noticeable running your finger nail across the race. I have never noticed any issues. Normal or not? Should it be replaced?

    Kinda weird wear pattern.
    #1
  2. Kiwiktm

    Kiwiktm Adventurer

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    Yes replace now. If you try to preload those worn bearing races you will end up with notchy steering and poor handling.
    Cheap and easy repair for you.
    Keep these bearings well greased and regularly adjusted.
    #2
  3. albani

    albani Adventurer

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    Replace them.
    Timken/skf l45449 and l45410
    #3
  4. DirtyADV

    DirtyADV Long timer

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    Replace if you ask me.

    If greased and adjusted properly they should last a long time.

    Mostly what kills bearing is corrosion.

    The bearing races in the steering stem can be hard to get out. Even with a blind bearing puller it was like they were welded in place, but with some freeze spray they came out quite easy with the puller.

    Did them on my dads bike that showed some neglect when it came to maintenance and it might have seen salted roads at some point in its previous ownership.

    Race on steering stem was cut carefully with a rotary tool and cutting disc to be removed, REMEMBER to install the new seal before the bearing race on the steering stem.

    /Johan
    #4
  5. COXR650L

    COXR650L Long timer

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    Thanks guys. I'll replace them.
    #5
  6. nk14zp

    nk14zp Long timer

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    Run a bead of weld around the inside of the races and they will practically fall out.
    #6
    sieg likes this.
  7. Stephen

    Stephen Long timer

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    My dealer just pushed the stem out of the lower triple then pushed it back in for me. Nominal charge, maybe none as I'd bought the kit from him. IIRC, the stock bearings are SKF or similar.

    And yeah, clean, lube and adjust. Here in the semi-arid semi-tropics, the grease dries out dries up turns to crap, things wear a little, clearance opens up and the pounding brinnells the races pretty suddenly. I don't doubt that in Sverige the corrosion kills them.

    Nothing like servicing steering bearings to make a bike feel new again.
    #7
  8. Loff

    Loff Adventurer

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    This the tool that I used to remove the race from my bike. OTC 4796 Steering Neck Bearing Race Remover. You can find the tool on Amazon.
    #8
  9. COXR650L

    COXR650L Long timer

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    Ill give a try running a bead of weld around the race. Never heard of that before.
    #9
  10. Parx400

    Parx400 Long timer

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    I can never get mine set correct. After beating the bike off road i get a notch.
    #10
  11. Blackalac

    Blackalac Been here awhile

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    Did they look like this[​IMG]


    Sent from my iPad using Tapatalk
    #11
  12. COXR650L

    COXR650L Long timer

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    I didn't look into the lower one, but based on how it felt, I'm guessing it did.
    #12
  13. RedRupert

    RedRupert Brit in the Soviet Union

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    The bottom race is the one that suffers the most, but you can't detect wear when the weight of the bike is off the front because the weight of the forks is resting on the TOP bearing.

    My bike suffered premature head bearing wear until I started using black molybdenum disulphide grease with graphite. Never seen this recommended, but it works great.

    When installing the new bearings seat them by tightening the 27mm nut tightish - I think around 80 Nm, but check in a factory Jap manual, as KTM don't mention this - then back off until you have slight resistance. If you feel a knock after a few 100km, nip-up 1/8th turn at a time.

    Carry out a visual check every time you refresh the fork oil - that's every 15k km or so: :-)
    #13
  14. DirtyADV

    DirtyADV Long timer

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    On newer models they list a torque on the head stem nut, like 12 or 14 Nm. Have been using what in the manual with good success since I found it.

    /Johan
    #14
  15. MortimerSickle

    MortimerSickle Semi-Adventurer

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    I used a long, flat-tipped punch to reach through from the opposite end.

    Work around the circumference, tapping and the race comes out easily.
    #15
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  16. COXR650L

    COXR650L Long timer

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    I just got them changed. Welding was the way to go. 30sec per race and they fell out. Thanks for the tip!
    #16
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  17. chevtech

    chevtech Long timer

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    Chances are, he already had notchy steering and just had gotten used to it as it got worse!


    ;)


    Todd
    #17