Smaller gas tank for a 640 Adventure

Discussion in 'Thumpers' started by ajaxauto, Jul 29, 2005.

  1. ajaxauto

    ajaxauto Adventurer

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    Since i have been trying to sell this bike and still have it and have been riding it like a real dirt bike.My question is there a smaller gas tank avalible like maybe
    arount 3 or 4 gallons. Do not need a 7 gallon gas tank .Is there a factory tank or maybe a IMS or Clark tank .If i do not sell soon will strip it down and ride it like a dirt bike do not like the street thanks John
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  2. markjenn

    markjenn Long timer

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    I'm not aware of any third-party tanks, probably because if the four-point mounting to the fairing bracket and frame, plus the integration with the front fairing. You can fit a tank from other LC4s, but to make it work, you have to buy LOTS of ancillaries and it gets prohibitively expensive.

    Why not just not fill it up? It's not very bulky between the knees and the weight of the unfilled tank isn't very high.

    If I were just going to ride dirt, I'd adjust the price, sell it, and get a different bike. Wrong tool for the job.

    - Mark
    #2
  3. meat popsicle

    meat popsicle Ignostic

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    There is the 18L enduro tank that probably could be retrofit, with changes to the fuel lines (disconnect fuel pump?), mounts, and the seat. Not sure if there is a smaller one - maybe a supermoto one?

    search for KTM Parts on the web and you will get a bunch of suppliers - but you might wait for others to chime in on the details of such a change.
    #3
  4. Renazco

    Renazco Formerly AKA Boejangles

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    SXC or enduro tank will work (same frame) but also consider that the seat has to work with the tank.
    #4
  5. meat popsicle

    meat popsicle Ignostic

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    :evil
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  6. soloyosh

    soloyosh Dad and husband

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    Doesn't the faring mount to the Adventure tank as well?
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  7. meat popsicle

    meat popsicle Ignostic

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    yep. probably want the LC4-E fairing as well.
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  8. Renazco

    Renazco Formerly AKA Boejangles

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    Yes it does.

    but if he wants to lighten up the bike you might as well turn it into an Enduro version in which case MJ makes a good point. (wrong tool for the job) because the Enduro version is still heavy for a dirt bike.

    I rode the 625 Dakar tryout bike out in the desert (625 SXC with 640 fairing and tank) and it felt lighter but it wasn't convincing enough for me to give up my 640 Adv.
    #8
  9. Rocamojo

    Rocamojo Toasted on both sides

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    I've done exactly what you are describing with my 00 Adventure. I discovered I almost never rode the Adv on the street.

    You will have to buy a new tank obviously and depending on which tank you pick, possibly a new seat. If you want to retain a headlight and/or street capability you'll find the stock headlight, shell, and mounting bracket from a 98 or later LC4 will work the best (i.e. bolt on). The LC4 headlights clear both the ignition lock cylinder AND the tab used to mount the Adv headlight frame. Then you will need to get real familiar with your owners manual wiring diagram!

    As for which tanks fit, the tanks from 98 and later LC4s fit the best including the 18L (although I never ran one of these, just test a test fit. It was nearly as wide as the stock Adv tank). But you will have to change the seat to a later LC4 style. You can use the stock seat if you use a 97 RXC or some of the other earlier tanks. But a 96 RXC tank won't work with the stock seat, it uses an EXC type seat. If you go with the stock capacities for the earlier tanks they bolt right up with a little mount tweaking. If you go with the IMS large SXC tank (which I did) you will need to reform the tank with a heat gun to clear the radiators as the 98 and later radiators for the Advs are wider than those used with the earlier tanks. Others can probably provide further year model details.

    All of this requires a fair bit of fiddling to get right, especially the wiring. I can swap either way in about 90 mins. Others on this site have done the same and have posted pics, probably worth a search.

    However, I almost always use the Adventure set up now. The dirt capability with either set up is about the same as far as I can tell, and the bike loses that Dakar-style coolness when stripped. IMHO, the best thing you can do to enjoy it more as a dirt bike is get the suspension set up by a professional. The bike goes from being a street bike to a very capable large (its still large even after removing the Adv tank and fairing) dirt bike.
    #9
  10. ajaxauto

    ajaxauto Adventurer

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    I want to strip it down change the tank get rid of the fairing ,spedo and all the
    that stuff change the seat change the pipe try and make a stripped down almost still legal dirt bike .Also rework the suspention.What are my option no other 650 type bike is as good as the KTM 640 And i will not ride RED .Plus Yamaha Blue stops at 450 and that is not street legal.
    #10
  11. Renazco

    Renazco Formerly AKA Boejangles

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    Sell it and buy a 526 EXC and add cush wheels..
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  12. ajaxauto

    ajaxauto Adventurer

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    How does that work first i can not even sell this one for 4500 and then if i did a good 525 which is not as fast as a 640 would cost like 7 k i think i will save 3k and ride the heck out of what i got maybe not as good as what i want but a lot cheaper .Thanks everyone for all the responce John
    #12
  13. dino2000

    dino2000 No Bad Daze

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    PM'd ya.
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  14. ajaxauto

    ajaxauto Adventurer

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    Atk are bikes i know alot about.Back in 1984 at the finich line of Barstow to Vegas i was looking at Cris Crandles ATK 560 which he just over alled the race on.I had a Horse power C and J framed xr 500 and wanted a ATK.Talked to
    Horst Leigner the owner and order one.What a deal i got i painted his car and 2 thousand dollars got me a new bike.I raced that bike until 1989 when the electric start604 came out.Warren Reid got the first one and i got the second one ever made.Deal again painted his wife car and another 2k got me a e button 604.At the dist 37 races i was the only one with a e button.What a bike won many races on that bike.In 1999 rode my friends new ATK which we won Vegas To Reno on it was more of a dual sport bike then a race bike.After the race i called ATK in utha since Horst did not own it any more and asked the people there if i payed more would they help me build a new ATK race bike .The answer i got was you are not the custermer we are looking for anymore ATK is looking for mid 40 yearold guys wanting easy riding dual sport bikes.I said to them are you telling me to go buy a yamaha 400 and ATK said yes so in 1999 i got a yz 400 .My buddy and i raced all 5 BEST IN THE DESERT
    over 40 class that year and won them all.To this day ATK still will not work with me on a new bike.I still have my old 1989 604 maybe i should dual sport that bike .I sure miss the power to this day i have never ridden a faster dirt bike it would go over a 100 and still keep pulling. Might notbe the best handleing bike but it sure was fast .
    #14
  15. Rocamojo

    Rocamojo Toasted on both sides

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    John,

    If you do strip down the Adv, I 'm guessing you won't be able to hit 300lbs no fuel without losing some counterbalancers and converting to wet sump. That's even if you use the SXC aluminum subframe and aftermarket exhaust. If you want to go under 300, I don't see how you can do it without either a lot of titanium and carbon fiber or losing the electric start.

    FWIW an old buddy of mine had an ATK framed XR600 in the 80s that he desert raced. I actually liked that bike but often wondered what it would do with the Rotax motor.
    #15
  16. meat popsicle

    meat popsicle Ignostic

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    christian would like to discuss this conversion more, if you please.
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  17. christian

    christian Long timer

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    just saw this thread coming up.. thanks!

    yes I am interested at a 640ADV and I have a 520EXC CA plated that I can trade. :evil
    #17
  18. mangas

    mangas n00b

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    Hi! Sorry to bring up such an old thread, but i have a very similar situation. Except it's more due to the lack of availability of original ADV tank, which cracked and is leaking on mine.

    I was hoping you could clarify a few things. When installing the smaller 12L or 18L enduro or sxc tanks, do you have to go for the same years ('99-'02) or can get a more recent one? Most places say you have to match the seat as well, is the year important here as well? Does the rest of the seat fit the bike without issue or do i need to change the rear plastics too?

    Also, if possible i'd like to keep the original headlight and fairing. I was wondering if it's possible if i dont plan on converting mine to enduro completely or do they not work well with the smaller tanks?
    #18
  19. hajoktejnSI

    hajoktejnSI Been here awhile

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    I have an 18l enduro tank at whome. Test fitted it and it's approximately 3 centimetres narrower on either side; so, no you can't bolt the fairing on it.
    How big is the crack? Did you try fixing it?
    #19
  20. mangas

    mangas n00b

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    The crack is approximately 3mm wide and 15mm long. It seems to be worked on by the previous owner and cracked again. It's in a
    difficult spot where the tank rests on frame and seat pushes against tank. This is after i removed the glue / weld bits that had shattered:
    IMGP8643sm.JPG
    The thing with fixing is, that nothing both sticks to nylon and resists gasoline.

    What about the 18L seat? Will it work on Adventure? I wonder if i could simply make supports for fairing that could be bolted to radiator pucks, since they are not used by smaller tanks anyway.
    #20