Add me to the cracked fuel tank list

Discussion in 'Parallel Universe' started by lepoer, Sep 29, 2010.

  1. JohnnieBoy

    JohnnieBoy Been here awhile

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    Yup, mine is cracked too. 2011 with 3500 miles in it
    #81
  2. Jack Secret

    Jack Secret The Cunning Linguist

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    Mine is cracked. 2010 with 2200 miles.
    #82
  3. Fixalot

    Fixalot Adventurer

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    When I went to the dealer to have my second tank replaced I was informed that they still had my first tank that was replaced. Seems that they did not return it to BMW within a specified time frame. I offered them $ 100.00 and I now have a slightly cracked spare. In hind sight I probably wasted $ 100.00
    2nd replacement tank shows no sign of cracking after more than 6 months.
    #83
  4. Motorfiets

    Motorfiets Long timer

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    send it to a mold maker and have them make us a bigger tank :deal
    #84
  5. JRWooden

    JRWooden Long timer

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    Keep it in the corner, I'll bet you can recover your money with ease at some point when someone punctures theirs ...
    New tank is $800+ :eek1
    #85
  6. westcoaster9

    westcoaster9 Blueback

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    My F 650 GS is cracking on the filler side and the build date was June 2008. Bentley Motorrad in West Kelowna "Service Dave" has never heard of this problem although he admits to only being in that job for 7 months.
    I talked to BMW direct and they said the Dealer must contact them directly. Dave "Bentley Motorrad" said they are out of the picture as it's off warranty. This is not looking good here.
    Has anyone had experience with hot glue or JP Weld fix? Does it hold up?
    #86
  7. JRWooden

    JRWooden Long timer

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    Yeah.... sigh ... I'm on my second tank and it has started to crack also .... :cry
    My luck is slightly better than yours ... I got first tank replaced just before the end of warranty so 2nd tank should be free within two years ...

    I've not heard of anyone that has attempted to repair the crack ...
    The cross-section is thin and I can imagine the stresses being pretty large at times ...
    full tank of gas and big air off a whoop-dee-doo....
    I wonder if there would be any way to put a strap under the tank to take some load off the outer shell without having the thing look dorky? The tank is double-wall ... what's cracking is the outer shell ...
    #87
  8. LukasM

    LukasM Long timer

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    Have we ever found out if the Euro tanks are different on either F650 or F800? I have not read of a single cracked tank on the German forums.

    I've got a spare in the Flea Market if one of you out of warranty guys needs one.
    #88
  9. JRWooden

    JRWooden Long timer

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    Lukas:
    That's a great question ... and I'm not sure what the answer is ........
    What part number does the Euro fiche list as current?

    Something funny is going on here in the USA, the current P/N is listed as: 16117704799 (old part was xxx798)
    but then the fiche says "only in conjunction with" ... (like you have to buy it with all the accy. parts)
    but then no price is listed ....
    #89
  10. Westy99

    Westy99 Been here awhile

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    When mine was replaced, they had to order one from the Motherland, we'll see how it holds up. I believe it was the newer part number.
    #90
  11. Snowy

    Snowy Long timer

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    Just to add another level to the cracked tank saga.

    On an outing recently I noticed a large build up of clay on top of the swing arm. It was gradually drying and it had a very definite imprint of the underside of the fuel tank in it.

    When bottomed out, ie all the shock stroke is used, the swingarm appears to come within approx 20mm of the underside of the fuel cell.

    So, if the clay dries, and then I bottom.....what happens?

    If small rocks are present in the clay and I bottom?


    In my humble experience, if it CAN happen....it eventually will.
    #91
  12. JRWooden

    JRWooden Long timer

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    #92
  13. westcoaster9

    westcoaster9 Blueback

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    Small correct here or "Achtung"
    --in Germany it's the Fatherland
    #93
  14. Westy99

    Westy99 Been here awhile

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    Either way it took a month. :lol3
    #94
  15. westcoaster9

    westcoaster9 Blueback

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    Getting back to the subject matter, cracked gas tanks, lets look at alternative solutions to warranted replacement like to 2 part epoxy used for plastic bumper repairs--or marine epoxy B52 --or J P Weld --or Bondo -or-or -etc.
    Who has tried what and has it help up.

    Paying $1000 to have the dealer replace the tank is certainly not going to be my first option--how about you?
    #95
  16. ebrabaek

    ebrabaek Long timer

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    When Mine cracks..... I will make my own out of Carbon fiber.....and special epoxy. Might even squeeze out another gallon....he-he.... It is only the outer shell that is cracking.... so I would imagine many will just continue to ride with it cracked.....:thumb:thumb

    Erling
    #96
  17. westcoaster9

    westcoaster9 Blueback

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    Dear Ebrabaek,
    Seriously here, if you have the molding skills and epoxy knowledge to make your own tank you are certainly knowledgeable enough to comment on the best patch/calking epoxy based repair product to use---
    Please share you vast knowledge here as there is many of us that don't have your education in plastics.
    My approach would be to take a die grinder, chuck up a fine tipped steel router and cut a v-notch in the outer shell along the crack outline.-- lets say 1.5 to 2mm deep. Then take some of the fine plastic material routed out and test the epoxy to see if it dissolves the parent material. This should indicate it will bite into the cracked edge and hold up.
    Now old chap-- please critique this approach with your vast background here.
    Old Blue
    #97
  18. ebrabaek

    ebrabaek Long timer

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    No epoxy will dissolve the polywhatever...:D ( tank)... but if you use poluester resin..... some might. The trick is first try to find out the chemical structure of the cracked tank, as there are a lot of different composites used nowadays. Some cannot be fused once cured. Epoxy will stick to just about anything....but again some polymers are inherently " sticky" and nothing except the proper glue will bond them. This is what I would do. Try to find out what native bonding material that would work. That would incorporate a call to the tank manufacture, and they might not release that information. So most likely I would proceed with the following..... Try different epoxy's... (I usually stock 6-8 different types).... after mixing each..... "spill" a drip on the tank exteriour after cleaning, and wiping with acetone. After cured...take a sharp knife.... simply try to pry off the "drips" see which one stick the best... When you find one that works.... you'l know... it simply wont come off. Then try to clean the area to be patched...with isopropyl alchohol....then acetone.... Mix the winning epoxy.....add some very fine cut strands of Carbon fiber for color and added strength...... carefully fill the crack...... perhaps taping off the area with aluminum tape...... then cure....sand.... your done.....This is assuming that the cracks are only in the outside tank, and the inside is not breached. If it is... Make a hole tank, as it would be impossible to fix it through the outer layer......:thumb:thumb

    Erling
    #98
  19. westcoaster9

    westcoaster9 Blueback

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    Thanks much for that well outlined approach. Questions arising from above. Why aluminum tape? As the seam of the crack is always dry I must assume its not leaking Further, some threads back somebody said that a dealer had replaced his tank and the old tank was cut open to show its a laminate construction made with an inner fuel bladder and and outer decorative shell, which is where the cracking takes place.
    #99
  20. ebrabaek

    ebrabaek Long timer

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    Absolutely.....:thumb. I usually use aluminum tape to mask.....as regular paint tape get's saturated by the epoxy, and can be a mess to remove....as they do not offer a good barrier. But in reality... what ever you have on hand will do.:thumb:thumb

    Erling