950 A gas tank problum

Discussion in 'Dakar champion (950/990)' started by cagiva549, Jun 29, 2008.

  1. cagiva549

    cagiva549 whats a cagiva

    Joined:
    Oct 10, 2004
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    6,284
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    Time for maintaince on my 950 , while stripping the tanks the top nutsert attaching the front fairing to the top of the tank broke loose in the tank . I love nutserts in plastic , I'm thinking I sure hate to throw away a 900 dollar tank because of a crap nutsert . I pulled the tank with the fairing attached and set it aside to continue with the work . A day or two latter after cooling off a bit and quite cussing KTM engineers I am trying to salvage what I can so I grind the head of the bolt and remove the fairing without damage then decided to chuck a drill to the remaining bolt and see if I can melt it out of the tank and maybe glue a new nut in the tank to secure the fairing with . Just by luck the drill was in reverse after a miniute or so and things getting fairly warm the frozen screw let go and unscrewed . I thought this is good .
    Afterwhile I went back to the tank to finish trying to get the damaged nutsert out and discovered it had welded itself back in the tank from the heat . Again this is good , I ran a tap in it to chase the threads and it held tight so maybe all is good . I will know next time I need to pull the fairings , also know what to do next time . The tail light nutsert let go a couple years ago so I trashed the old light and replaced it with an LED truck light . I wanted LED anyway . I really didn't want a new gas tank . SEYA
    #1
  2. gschwartzenberger

    gschwartzenberger engineer

    Joined:
    Jun 1, 2008
    Oddometer:
    6
    I have a bad threaded insert in my Supermoto tank. It holds, I think, but it is weeping fuel. Perhaps I can salvage it with some heat from a small butane torch or large soldering iron.

    I know, if I ever get around to it, I'll be sure to start with an empty, well ventilated tank.

    greg
    #2
  3. Hammer

    Hammer Hawlin' aZZ

    Joined:
    Apr 18, 2004
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    Would you record this for us? Get a survivor to put it on Youtube?
    I don' wanna wish you bad luck, but I think you might want to rethink your approach here.
    #3
    nk14zp likes this.
  4. HellsAlien

    HellsAlien a has-been that never-was

    Joined:
    Nov 16, 2004
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    3,848
    Location:
    Baja Sur winter, Columbia City summer
    I've replaced/fixed the threaded insert at the top of the tank. Is no fun, but is possible. Standard McGyver stuff. The top hole can be accessed thru the gas tank fill with tools. I built ships-in-bottle years ago, is similar, but you can't see thru the KTM "bottle!"

    I used a round insert nut w/ 3 teeth, common for wood holes, available any good hardware store. Remove the teeth, ruff up w/80 grit. Drill/fill thread w/ JB weld. Retap and install metric Helicoil, it grabs enuff metal to work good.

    Make tooling to roughen interior of tank w 80 grit. I used the nut itself as a mandrel to hold custom mini sanding disks. Fished it thru and did a back-counterbore/sanding job to the tank interior. Note: this is a rotomolded tank. The liner coating is something like a cross-linked polypro, slippery, but JB weld will adhere if ruff and clean. Yes, I tested that. Advise you do too w/ whatever you plan to use for glue.

    Then, a good cleaning of tank interior. Then butter up new nut and tank w/ JB weld. Fish the new nut thru from the inside on a wire and locate in the tank. Butter up the front side of the nut/tank. Install fairing piece to hold location of nut correctly (use grease on the capscrew.) Working just fine a year later, no problemo.

    The stock insert nuts are like metric acorn nuts, just a short hex on the OD, no more than a jamb nut would have. SST and shiny, they won't take much of an overtorque or bending load before they spin in the tank plastic.

    I always use silicon spray on these fasteners to prevent corrosion/binding and am careful not to overtorque as the fix is a PITA! Be sure the fasteners won't bottom out too.
    #4
    chevtech likes this.
  5. Young-Gun

    Young-Gun KTM Tragic

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    Dec 6, 2005
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    1,307
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    Brisbane, Australia
    Does anyone have a photo of what one of these nutserts looks like when removed?
    #5
  6. gearheadE30

    gearheadE30 @LC8Adventures Supporter

    Joined:
    Jan 20, 2012
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    Indiana
    I repaired one with Loctite 290 and haven't had any problems since. It's designed to be applied to fasteners that are already installed, so I took the tank off, set it on its side, taped over the threaded hole, and got as much loctite in there as possible. That was 4 years ago, and it's been fine ever since.
    #6
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  7. aanichols

    aanichols Racer at heart

    Joined:
    Dec 6, 2012
    Oddometer:
    491
    Location:
    La Verne, CA
    I would stay away from the flame , but the soldering iron is the right approach. I cracked my 950 tank and after some research figured that plastic welding is the best approach. My soldering iron didn't put out enough heat, but a Harbor Freight plastic welding kit did the trick....under $20. The 3" crack was in the lower area, and hasn't leaked a drop. I drained the tank, cleaned the area, and that was all the prep I needed.
    #7
  8. chevtech

    chevtech Long timer

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    This is similar to what I have seen done my some other inmate, that did a high quality repair (don't know the thread...sorry). He didn't helicoil it though, just installed new factory metal nutsert (not the right term, theses are different than a nustert). You could use a good plastic two part expoxy which would probably adhere to the plastic better, and the metal not quite as well, but given that the plastic usually gives up first I would probably go that route were it me!

    Good luck!


    :beer


    Todd
    #8
  9. chevtech

    chevtech Long timer

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    I seem to remember they were available separately through KTM, they are usually pretty good about that kind of stuff. Replacing with factory would be my route of choice, no special bolt for one side, and none of the issues with a helicoil given that they can be cantakerous about being removed so often like we have to on our tanks for maintenance!


    Todd
    #9
  10. cagiva549

    cagiva549 whats a cagiva

    Joined:
    Oct 10, 2004
    Oddometer:
    6,284
    Location:
    Cypress Tx
    After the first incident with my bike I coated every screw that threads into plastic with antisize and it's been trouble free ever since . Also helicoiled all threads in aluminum that must be removed for regular maintaince before they became a problum . Life has been good , so good I just bought another 04 as a backup bike . Original is closing in on 100 k miles , new one is at 50 k miles .
    #10
  11. mtbtweety

    mtbtweety Adventurer

    Joined:
    Aug 16, 2009
    Oddometer:
    79
    Location:
    Cumming, GA
    Anyone successfully documented a repaired nutsert in the fuel tank? I can see the nutsert / acorn nut on the inside of the tank via a boroscope and the tank seems to be intact. The nutset is (now) drilled out enough to remove the screw that was bound in there. I apparently crossthreaded the heck out of it, and really don't want to trash the tank. I'm trying to determin if it makes more sense to remove the nutsert from the outside, insert a new nut in there, and epoxy the crap out of it, or try to build a ship inside a bottle as mentioned before, having no experience with bottles.....
    #11