950 Adv brake rotor / caliper interference

Discussion in 'Crazy-Awesome almost Dakar racers (950/990cc)' started by grant22, May 28, 2013.

  1. grant22

    grant22 Been here awhile

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    I had to do a trail side front tube replacement yesterday. I am new to adv bikes, but not new to dirt bikes / KTMs.

    While removing the front wheel, I thought I was careful to catch any spacers that may fall, but anything can happen. I remounted the wheel, very similar operation to my EXC bikes, pumped up my front brake pressure, checked for a free spinning wheel, etc etc etc, and away I went.


    About 50 miles down the highway while exiting (and braking) I felt something weird in the front wheel. I pulled over and found this:


    [​IMG]
    [​IMG]


    According to the ktm parts diagram, there is a spacer on each side, but on wheel removal and re installation, this is what my spacer situate looks like:


    Rider's Left side:
    [​IMG]


    Rider's Right side:


    [​IMG]


    It appears to me the rider's left side has a spacer while the right side is spacer-less (I think the axle is stepped, acting as a spacer). But somehow, the wheel went right (rider's right) and the rotor started hitting the caliper support (the rotor has a chunk of aluminum and the gouges are all actually melted aluminum).


    Like I said, I probably did something wrong (and am very lucky this didn't cause something uglier).


    -what did I do wrong to cause this?
    -is there a spacer on the rider right side that I'm missing?
    -has this happened to any of you?


    I'm going to start tear down and assess the damage and order parts, but would like any of your help to keep this from happening again.


    Thanks!
    #1
  2. gefr

    gefr Life is a trip

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    http://www.munnracing.com/
    you should have these two spacers at both sides:
    part No #60009012000
    part No #60009013000 this seems to be missing
    Nothing serious
    Cheers.
    #2
  3. brents347

    brents347 Trusting my Cape...

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    It looks to me like your spacers are there. On the Left side of the bike the spacer is bigger and visible, but on the Right side it is thinner, doesn't stick out of the hub much and the stepped axle sits against it. If this spacer is there, then the only way for the wheel to shift to the right and rub a rotor is if the axle is not all the way seated into the fork leg. The end of the axle should be flush with the outside of the fork leg. It is easy to get burrs on the end of the axle that make it not want to slide all the way in.
    #3
  4. HellSickle

    HellSickle Scone Rider

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    Looks to me like your rotor wasn't placed between the brake pads on the right side. I think you have both pads on one side of the rotor.
    #4
  5. roookie1

    roookie1 Been here awhile

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    +1

    Did in on a Suzuki once, sparks were flying all over.. :deal
    #5
  6. DSM8

    DSM8 Where fun goes to die....

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    ^^^ THIS ^^^

    It looks like both spacers are where they need to be the above is the only thing that makes sense. Pull the wheel and take a look, take pics too.
    #6
  7. LocuL

    LocuL Gnarly Infantry

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    Yep, both pads are on the other side or you just lost it while changing.
    #7
  8. Orangecicle

    Orangecicle On a "Quest"

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    That could be the case. Hard to say without taking it apart and looking.

    Note that the torque on the axle net sets the proper spacing on the nut side. It's a little tricky to get that side set properly and usually requires me to get it close and then tighten the pinch bolts on the OTHER side to torque the nut down. Then you tighten the pinch bolts on the nut side and loosen the pinch bolts on the other side. To set the non-nut side, you usually have to just check the spacing of the brake rotor in the brake caliper. The rotor should be centered in the caliper. Set it by eye and then tighten your pinch bolts. On a KTM, this usually means that the axle is slightly recessed into the holder, but it really depends on your bike.

    The other thing to know is that you have to take the caliper off of the caliper mounting bracket every now and again and grease the pins that the caliper slides on. Pack those little rubber boots as full of grease as possible and reassemble. If the caliper pins get corroded, the caliper will not slide around as it should, and getting your rotor spacing right becomes all but impossible.

    Hope that helps.
    #8
  9. brents347

    brents347 Trusting my Cape...

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    This is a really good point guys, but why is there melted aluminum BELOW the pad mating surface of the rotor? It seems to me, that somehow the caliper mounting bracket, not the caliper itself, has come in contact with the inner portion of the rotor.
    #9
  10. grant22

    grant22 Been here awhile

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    Thanks guys for all the insight. Haven't been home yet to disassemble. I'll get to it in an hour or two.

    Both theories are very plausible. The axle not being seated could have been caused by some sand or small gravel in there and it's totally possible I effed up getting the rotor in BETWEEN the pads.

    I had very little light to help me and the sun had set. Total learning experience for me for sure. Also, this is my first trail side flat repair. Over 10,000 miles riding my exc's in this desert and not one flat. So I'll put more thought into my flat kit (brighter flashlight).

    I'll keep u all posted as to what te outcome or cause is.
    #10
  11. grant22

    grant22 Been here awhile

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    Forgot to mention,

    The low chunk of metal is a mystery to me. Whatever it was cut an arced groove out of the caliper support. Almost like there was a bolt was there.
    #11
  12. DirtyADV

    DirtyADV Long timer

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    Have a spare caliper I could part with at an OK price.

    Full amount would go to my attempt to raise some money for charity.

    Depending on location not sure what shipping would land on.

    I tighten right side to be able to torque up the big nut, then clamp left side and loosen right side, apply brake, work the forks some.

    That lands the axle a little inside the clamp of the fork, about 1mm.

    While axle is flush with clamp disc and caliper makes contact, just a little doubt it would end up with the damage you have suffered.

    Good luck sorting it out and let us know what was wrong so we can learn from you mistake :freaky!

    /Johan
    #12
  13. DSM8

    DSM8 Where fun goes to die....

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    That might be what is left of your caliper piston if indeed that was what was contacting the rotor when braking instead of the pads.

    Cant wait to see pictures when you take it apart.

    :ear
    #13
  14. gefr

    gefr Life is a trip

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    Is it possible it fell during the tire repair??
    #14
  15. FakeName

    FakeName Wile E Coyote SuperGenius

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    Yes- happened on my EXC and I could not get the caliper halves apart. Finally broke them trying to do so. Apparently one can purchace the pins by themselves from a honda dealer, but not KTM.

    Now, they get pulled and greased every tire change along with the chain adjusters.
    #15
  16. Apple Jam

    Apple Jam Forest Flyer

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    This ^^^ EXACT thing happened to me,
    and my same rotor got rubbed same as OP's, but not as bad.
    I think THIS is the problem.

    CJ Racer was there (on the way to the KTM Rally last year) and he blamed me for manhandling my axle when I have flatted in the field, and then not cleaning the axle before jamming it back in with the wrong tool (he was right, I used a big stick :1drink).

    He said it wouldn't have happened if I had installed his blingy orange axle pusher that was sitting unused on my workbench as he spoke :lol3 Then he proceeded to showed me how to install and use his blingy orange axle pusher, because I'm an f'ing dork of a mechanic :deal

    I took my axle to the bench grinder to de-burr the outside, then CJ took a small round file to the inside, cleaned it and greased it, and it slid right home. It was probly only about 1 mm off from fitting in correctly, and my pads were thin, so it was enough to do the job to my rotor.

    My axle actually now sits about 1/4 mm inset from my rider's right side fork edge, but it aligns perfectly in the pads/rotors, because I had to grind that much off the end to make it fit in neatly. YMMV.
    #16
  17. grant22

    grant22 Been here awhile

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    DirtyAdv: I appreciate the offer, but all I need is the caliper mount. Plus, fom Sweden, postage would probably be murder. I could donate directly to the charity you speak of, tho.

    Here's the final tear down and assessment..........I still don't have an answer. I DO believe the axle wasn't quite flush or inset, but that wouldn't explain the lower groove of havoc that ocurred. Not having the axle seated all the way would explain the outboard side of the rotor contacting the inside of the caliper. THE GROOVE AND CHUNK OF ALUMINUM ARE STILL A MYSTERY TO ME, THO.


    Heres another pic before I dismantle:
    [​IMG]


    Wheel removed:
    [​IMG]


    Another angle (see the groove?) and no, the groove does not line up with the rotor bolts:
    [​IMG]


    Here's the rotor. The melted aluminum filled the SS gouges, should be able to sand this to usable:
    [​IMG]


    Here's the chunk of alu that was on the rotor spokes. It was lined up with groove. It popped right off the rotor spoke:
    [​IMG]


    Pads (shows the rotor was installed correctly between them):
    [​IMG]
    [​IMG]


    Here's a couple pics of the caliper bracket. It shows the depth of the groove and the profile:
    [​IMG]
    [​IMG]


    So once again, axle could have been seated another mm, but that doesn't explain the huge ass groove.
    #17
  18. HellSickle

    HellSickle Scone Rider

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    The deep groove could be explained by a rock that got jammed in the rotor or caliper during the flat fix.

    Are all of your sheet metal spring clips that hold the brake shoes in place?
    #18
  19. grant22

    grant22 Been here awhile

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    Yes, the retaining plate was in place.
    #19
  20. Lc8grrr

    Lc8grrr Vtwin madness

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    The RHS fork leg floats until you tighten the 2x8mm bolts at the bottom. They dont sit against a machined step in the axle. If you push the RH fork leg in too far you will force the fixed caliper mount onto the rotor. If you read the manual it says to bounce the forks after you have fitted the wheel back on to let the RH leg sit in the correct spot on the axle before you tighten the 8mm bolts. Bet it wont happen again [​IMG]
    #20