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Thread: K bike fuel tank

  1. #1
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    K bike fuel tank

    Can someone help me identify a fuel tank? I purchased it for a 1986 k75 and it wasn't right. The owner had no idea what it came off. So now I want to sell it and I'm not sure what to advertise it as. Pictures attached.

    Much thanks
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  2. #2
    3 Red Bricks
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    Let's see a picture of the bottom. It looks like it might be a K1100 tank.

    What's different from your tank?



    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
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  3. #3
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    Good call. That's a K100 or K1100 tank. The only K75 it will fit is the K75RT.

  4. #4
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    Not sure if it would fit the RT as I can't see the battery cover tabs (might be there, just can't see them from this angle).

    Won't fit the OP's C or a later standard as there are no prongs on the front for the radiator cover. Won't fit an S as the lower profile in the middle of the tank is wrong.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  5. #5
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    K bike fuel tank

    Here's a photo of the bottom.
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  6. #6
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    That's definitely a K100 tank. Probably 1986

  7. #7
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    Talking tank

    Lostboy

    Thank you so much for the input, much appreciated! Anyone else have any thoughts?

    Going, going.

    Thunderdome

  8. #8
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    K100 (std., LT, and RS) 2Valve after 5/85
    and K75 RT

    Will NOT fit K1, K100RS 4valve, K1100 (any), K75 std, K75 C, K75S

    Someone has altered the forward left nipple (fuel pressure regulator return). It should look just like the one behind it.


    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  9. #9
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    That port is as it left the factory. BMW was still using it for a check valve. The tank will work on a K1, but not a K1100RS.

  10. #10
    Benchwrenching PGlaves's Avatar
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    Quote Originally Posted by 98lee View Post
    K100 (std., LT, and RS) 2Valve after 5/85
    and K75 RT

    Will NOT fit K1, K100RS 4valve, K1100 (any), K75 std, K75 C, K75S

    Someone has altered the forward left nipple (fuel pressure regulator return). It should look just like the one behind it.


    OK, I'm fuzzy here but somewhere along here they had a filling with a ball check valve in the return line.
    Paul Glaves - "Big Bend", Texas U.S.A
    "The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russell
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  11. #11
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    That's what I like so much about this forum. Ya learn something new every week.

    Yep, once again lostboy is correct. As of course is Paul.

    I have never seen a fitting like that on any of the Bricks I have worked on. I looked in the fiche and sure enough it shows the valve (even for K75Ss). That got me REALLY curious! I looked at all the tanks I have (about 10) on and off bikes. None of them had the threaded fitting. They all had the nipple, just like all the others I have worked on EXCEPT MY BIKE! Sure enough, mine had the valve. 3 of my Ss were made in the summer of '87. My C was made in July of '86, but my "first litter" S was made in May of '86. So, evidently, between 5/86 and 7/86 they eliminated the valve and the threaded bung and went with the nipple.

    So that further narrows down what the tank is. Since they didn't make K75RTs prior to 1989, that eliminates them. The K1s didn't use the valve either and weren't made until '89. So that eliminates them for a different reason than I had originally thought (front mounts). That leaves K100 only.

    Assuming that Bmw eliminated the check valve and bung across the board before 7/86 and the fact that the K100s changed their tank mounting in 5/85, that suggests that that tank was built between 5/85 and 7/86 which would mean that that tank is off a:

    (Drum Roll Please). 1986 K100.

    WE HAVE A WINNER!!!


    Lostboy to the podium please!



    The color even confirms this as it is '85-'86 #618 Caribicblau Metallic.


    Last edited by 98lee; 12-02-2012 at 07:21 AM.
    LONG MAY YOUR BRICK FLY!

    Ride Safe, Ride Far, Ride Often

    Lee Fulton Forum Moderator
    3 Marakesh Red K75Ss
    Mine, Hers, Spare

  12. #12
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    By installing the check valve, or just its body, this tank may be used on the bikes I mentioned.

  13. #13
    BMW uber alles! Zagando's Avatar
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    Excellent detective work by the Lostboy-Lee Team!
    ---Jeff '94 K75S Berlina

    ex: R100GS/PD , K100RS , R75/5 , R60/2

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