Need repair instructions!!!! Can I do this myself?

Discussion in 'Thumpers' started by neepuk, Jan 9, 2006.

  1. neepuk

    neepuk Such a drag...

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    .............................Actual repair takes place on page 6. If you are repairing a paintable KTM 640 Adventure gas tank you may skip right to page 6. All kinds of fun info about different plastics and welding leading up to page 6. What NOT to use too...................

    Well S!*t, Yesterday Was FUN and hard on my bike! I went to Clear Creek Callifornia for a riding clinic and came home with a blown fork seal, a sore body, a muddy bike and worst of all, a cracked gas tank........Oh yeah, and a smile on my face that I can't wash off.

    Yes, I've checked the bleeping thread index and it seems to be that "plastic welding" is the best way to fix this. Can somebody point me in the direction of "how-to" plastic weld? I used to work in a ski repair shop and have a lot of experience doing "base welds" on skis and snowboards so I think I have the hands to fix it myself. Exactly what kind of materials would I need (minimum required) to do a perminant home repair? Can I build up some plastic to fill in the void space? The crack is on the tab that bolts the tank down so it's got to be strong! A step by step how to would be great.


    I drainded the tank last night and have been letting the fumes evaporate. Here's a shot of water flowing like gas!
    #1
  2. creeper

    creeper Still alive...

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    There is a (plastic) boat load of information here neepuk.

    C
    #2
  3. neepuk

    neepuk Such a drag...

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    Thanks Creeper. You're not kidding about there being a "boat load" of info. Has anyone else out there had their tank crack in the same place? Which method did you use?
    #3
  4. Rad

    Rad Done riding

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    Holy shit neepuk, how did ya do that?

    And....Go see Tom:lol3
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  5. creeper

    creeper Still alive...

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    Really big nutz? :dunno
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  6. Two Dot

    Two Dot Been here awhile

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    Sorry about the boom-boom neepuck. Good luck with the repair. Hope you are feeling better...

    Lets see some pictures...
    #6
  7. neepuk

    neepuk Such a drag...

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    I went out on a Doc Wong's riding clinic at Clear Creek. It consisted of some very basic and helpful drills in the morning followed by an afternoon ride. There were about 50 riders total and after the clinic session we broke up in to 7 groups. Most of the guys in the "big bike" group were on older "air-heads" and a few newer GS's too. So I joined up with a group af smaller bikes for a ride lead by Phil Douglas of Aftershocks. Sooooo much fun and I was riding well so I decided to follow Phil and a few others through an "optional" hill-climb......... I went down on the left side. I smelled gas and thought that I broke off the petcock. Nope, gas was pouring out from under my seat and the petcock was fine under all the mud. The bike went down pretty hard and just stopped without a bounce so the tank shifted back enough to F it up. I realized today after washing off most of the mud that I now have a blow fork seal on the compression side too.
    I'm gonna stop by Gary's plastics on the way over to see Tom in the AM.
    Gotta get er back on the road for another ride next weekend. Looks like I'm gonna have to learn how to do fork seals...or find a money tree.
    #7
  8. Donkey Hotey

    Donkey Hotey De Jo Momma

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    Hey neepuk bummer about the tank. Did you have any trouble getting the tank onto the bike when you were swapping plastics? My 97 tank went on pretty hard. I learned to lubricate the rubber mounts with soapy water before putting the tank on. After that, the tank would just settle right onto the mounts and everything lined up. IIRC the first time I put the tank on, it was preloaded at that rear mount (not good considering what's happened to yours). I hope you have some luck fixing it.
    #8
  9. neepuk

    neepuk Such a drag...

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    Now that you mention it, Yes, I did have to try a bit harder to get the orange tank on either bike. I'm thinking that the mould for the early tanks must have been a fraction larger. The hole in the tank is in the shape if a half-circle "washer" shape. I'm going to cut a piece of metal in the shape of the entire area that the bolt goes through the tank and bend it up in an "L" shape to act as more of a clamp to hold the tank on instead of just a washer. I'm hoping that it will prevent this from happening again. I'm no machinist so it won't be pretty but I'll post some pix when I get the "hole" thing figured out.
    Now I've got to decide whether or not to paint it once it's fixed. The more I ride this bike, the more I enjoy dirt-riding. It probably doesn't make much sence to have it painted just to go out a mess it up again. Maybe I'll just go with the half orange/half burnt-off paint fade to white scheme. I'll have to see it.
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  10. Donkey Hotey

    Donkey Hotey De Jo Momma

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    :lol3 Don't worry my friend, things aren't going to be getting THAT hot. If the nylon proves repairable, it'll all be concealed by the seat The biggest challenge in my opinion will be getting the gasoline residue off that area before trying to weld it. You might consider some aerosol brake cleaner and use the tube to clean out the joint before trying the thermal welder.

    I didn't check Creeper's link but you know that Harbor Freight sells those plastic welders, right? It's important to get the material right if you're using a filler rod. If the joint is tight, it might just melt and mend itself without extra filler.
    #10
  11. neepuk

    neepuk Such a drag...

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    I'm certainly going to need a little filler. The plastic is sprung open a bit from where the washer was holding the tank down. Do you know exactly what type plastic the 97 tanks are?
    #11
  12. Donkey Hotey

    Donkey Hotey De Jo Momma

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    I can't say for sure but I believe it's some sort of nylon. You can google around and find sites that tell you how to scrape off a sliver of the plastic and do a burn test. By the color of the flame and the smoke or lack thereof, you can get a pretty good idea of what it is.
    #12
  13. meat popsicle

    meat popsicle Ignostic

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    tough guy eh? bustin' your tank, which isn't easy on these bikes (older ones not so stout maybe? mine broke but it took a pickup truck broadsiding me...).

    Did you check the BLEEPING index?!?! :evil

    in Post I: Tank Repair Threads :lol3

    Turns out there is a ton of info on this in there as I had a fetish about it awhile back. Wanted to fill the nylon worn away by a asphalt low side slide.

    The OEM painted tank is made from polyamide (PA) and the rally tank (the cheaper unpainted hard parts one is polyethelene (PE). Happe says that if you have a place over the hill that welds waste water systems they weld PA and PE every day and can probably repair your tank. There are tricks to getting it right (like welding aluminum :lol3) so make sure you get someone who knows WTF they are doing (unless you like gas in your crotch).

    Loads more in the index including some info on using P-Tex candles for bodywork repair, on cheap DIY option that may or may not work in your application. For a big structural fix that could leak if not done properly I suggest you get a pro to do it.

    If that doesn't work out then you can pick up the hard parts rally tank for your bike at about a 1/3 of the cost of the stock replacement. And it's unpainted orange :evil and you can see the fuel level through the tank :evil

    First hit on google: http://www.ktmcycles.com/2006/tanks.htm
    $330 bucks

    ps - a bunch of threads on tank repair in the index... :jive
    #13
  14. neepuk

    neepuk Such a drag...

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    #14
  15. meat popsicle

    meat popsicle Ignostic

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    Don't forget to shop around - there might be some variance in the price from shop to shop or perhaps a used one about.
    #15
  16. JPI

    JPI Noob ????

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    I've done a few plastic weld jobs on tanks and minor body parts

    here's a good source for supplies, they also have rods to match all the bike colors, including ktm orange


    http://www.urethanesupply.com/5500ht.html

    Oh and the small 80 watt welder works just fine
    #16
  17. neepuk

    neepuk Such a drag...

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    I think my tank was either mounted wrong or something. that's why it broke. I still haven't figured out how I'm going to fix it yet but I think I've got a handle on why it happened.


    [​IMG]
    The bolt seems too long. Even with all the rubber mounts lubed and pushing very carefully it forces enough upward pressure on the tab on the tank to flex it about 1/4"......


    [​IMG]
    under the tank there is a metal washer covered by a hard cardboard washer.


    [​IMG]
    A lot of weight is resting on that cardboard washer. If I push down on the tank as if there is some weight in it the mount-tab really flexes.


    [​IMG]
    with the washer in place the tank does not rest on the rubber stops on the sub-frame.


    [​IMG]
    If I remove the washer the tank sits nicely on the sub-frame rubber stops and the seat goes on a little easier too.


    Was my tank mounted wrong? Does anyone else have this problem? Keeping in mind that this tank has been on and off many times, 36k miles on the bike it came off of and now a couple thousand on my 99 I'm thinking that this may be a problem you may have in the future. Check in to it on your bike and see if the bottom of the tank is getting worn near the mount bolt.

    I'm thinking that I might even do away with the mount bolt all together and make a large strap to go over plastic from left to right.

    Any thoughts or better ideas would be greatly appreciated.
    #17
  18. Bob

    Bob Formerly H20Pumper

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    Sorry about your tank problems!

    Last year at Vrago's Tech Party, I rode with a guy that had broken his tank on a ride in Idaho?? He fixed it and it seemed to be holding fine.

    You might PM vrago or boejangles for the guys name and how exactly he fixed it.
    #18
  19. meat popsicle

    meat popsicle Ignostic

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    This parts fiche should give you an idea of what should go when in that mount:

    [​IMG]

    ps - I haven't heard of any other problems with that mount.
    #19
  20. neepuk

    neepuk Such a drag...

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    Once again I find myself typing a very odd phrase..... Thanks Meat. The fiche shows me that my tank was mounted right. It just didn't work that way for me. I'm going to pretend that I'm an engineer on this one and do it my way. So far I've removed the under washer and cut down the mount-bolt about 3/8 if an inch and the tank now slips on with ease and sits nicely on the rubbers.
    [​IMG]

    [​IMG]

    Tomorrow I'm off to the hardware store to find a new way to strap it down. Maybe a piece of metal cut in the shape of mount tab on the tank to spread out the pressure evenly over the entire surface.
    #20