EXC Subframe cracks

Discussion in 'Thumpers' started by HellSickle, Mar 9, 2012.

  1. HellSickle

    HellSickle Scone Rider

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    I noticed my '06 450 and 300 EXC both have cracks in the upper subframe where it bolts to the main frame. Both bikes may have been like this for years. It looks like a hollow tube, that have a solid plug in the end.

    Anyone else observed this? Should I yank the frames and have them welded up, or will the solid plug essentially make this unnecessary?

    [​IMG]
    #1
  2. Hayden#69

    Hayden#69 Been here awhile

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    My friends 2002 400 SX is like that. My 03 450 EXC is like that and my other friends 04 450 EXC is like that. Doesnt slow us down any.

    Hayden.
    #2
  3. jrproper

    jrproper Been here awhile

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    Every KTM sub-frame I've seen looks just like that... wouldn't worry about it.
    #3
  4. theGrinch

    theGrinch SNF Dream Riders

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    As is my '06 EXC and every KTM I've seen.

    I think it's factory for less weight...

    ... hence the faster bike. :D

    If someone has a pic of one not "cracked" please post.

    :freaky

    .
    #4
  5. HellSickle

    HellSickle Scone Rider

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    Thanks guys. What a relief. One less thing on the list to deal with this spring.
    #5
  6. Skinner

    Skinner Mr.KTM

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    Those are ripples from the time warp! Slow down!
    #6
  7. Safeman

    Safeman n00b

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    #7
  8. Switchblade315

    Switchblade315 Long timer

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    Almost everyone I've ever seen is like that.
    #8
  9. HellSickle

    HellSickle Scone Rider

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    Thanks! Great fix.
    #9
  10. Stphnw8

    Stphnw8 n00b

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    Nearly all ktm's ( from 65cc upwards) I've seen at my sons moto x club have done the same in exactly the same place.
    Most of them have never had any problem with the crack growing or opening up and these kids are jumping very large table tops with no probs at all.
    My local ktm dealer says he's never seen it before..........

    Ktm----- Sunday = ATM -------Monday
    #10
  11. blake716

    blake716 nine toes

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    Same here. All of my KTM's have had the exact same cracks.

    No worries.
    #11
  12. Off the grid

    Off the grid Seeker of the Unf

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    The metal that's cracked is just the casing. The solid core is what's important. And like others said, every KTM I've ever seen has identical cracks.
    #12
  13. HellSickle

    HellSickle Scone Rider

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    You are missing the point. Some folks have an irresistible urge to fix things like this, making them better, faster, stronger. (present company included)

    If I had my own TIG, all three of my EXCs would be getting the same fix.
    #13
  14. woodzrider

    woodzrider Been here awhile

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    I had an '06 exc 450 (which I wish I still had). Took it apart at about six months new to check thing out, It was not
    cracked then. A year later I had the very same cracks and the plugs were just starting to loosen a bit. Being as I can TIG weld, I cleaned the offending crack, slightly V'd the crack and welded it back as well as ran a bead around the plugs and re-assembled. Never noticed anymore cracks up until I sold the bike a little over a year ago. My observation is that the plugs are slightly pressed into the end of the tube and being as the tube is extremely soft
    alum, the press fit fatigues the material enought to cause a stretch crack over time due to vibratioin and riding.
    Just my.03..........
    #14