Auxiliary tank design for KTM 690 Enduro

Discussion in 'Some Assembly Required' started by bibo01, Sep 13, 2019.

  1. DRjoe

    DRjoe Long timer

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    Bad idea, in what way?
    #21
  2. plumer1kt

    plumer1kt Adventurer

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    That's a V-shape fuel tank and that tube is there to vent the rear part of the tank.[​IMG]
    U shaped vent tubes don't work if fuel goes in the lower part of the tube.
    That's why every external vent hose looks like that [​IMG]
    If fuel goes inside the hose ,either will fall back in the tank or will fall out.A non return valve helps to fall back in the tank only.But will never trapped.
    .
    "Vent must be in the highest point of the tank and the hose must not be u-shaped."
    We don't want fuel trapped inside the u-shaped hose or the tank will not breathe unless there is a sufficient amount of vacuum to suck the trapped fuel out letting the air pass.
    Another way is to make a pass for the air through the fluid by moving the tank back and forth (off road riding).
    And that is the reason for the huge diameter of that tube.Vent hoses don't need to be huge.
    .
    That makes it a bad idea for me too.
    UNLESS THAT TUBE IS THERE FOR OTHER REASON.
    #22
  3. DRjoe

    DRjoe Long timer

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    The pipe has two jobs.
    Firstly it is there to vent the rear of the tank when filling.

    Second job is to hold the seat steady.
    The seat base is made of plastic and molded so it clicks on to that pipe and then theres on bolt at the rear just to make sure seat doesnt want to come off.
    #23
  4. DRjoe

    DRjoe Long timer

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    Also having a U in the breather that will collect fuel will not cause starvation problems as long as the amount of fuel trying to flow out of the tank at the bottom is greater than the amount of fuel trapped in the vent hose there will always be enough pressure difference to push the fuel out of the breather hose and into the tank.

    The one bad thing with having a low spot in the breather that collects fuel that i have come across is when it suddenly spits the fuel out on your crotch because then tank pressurised for one reason or another.
    #24
  5. DRjoe

    DRjoe Long timer

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    Well when mortaygo brings his round to the workshop i’ll have a look at it.
    Looks like the design of the rear end lends itself well to a couple of tanks.
    #25
  6. BygDaddee

    BygDaddee Where do I get a pie

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    He’s too busy with DR’s now :hmmmmm
    #26
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  7. MotoPolo

    MotoPolo So many places, so little time Supporter

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    I'm just thinking that my anatomy will not enjoy the landing:becca
    #27
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  8. WILL_S

    WILL_S OUTLAW POSTIE 001

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    Yes very bad idea
    Here the rider has to keep wheel standing that vstrom to allow it to vent :lol3

    #28
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  9. DRjoe

    DRjoe Long timer

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    Hasnt been an issue so far.
    Theres plenty of cushion above it.
    #29
  10. bibo01

    bibo01 Adventurer

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    My first 10cm high L/R tank samples! :D 20191008_102108.jpg
    #30
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  11. kito

    kito Been here awhile

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    #31
  12. bibo01

    bibo01 Adventurer

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    Probably the maker - @DRjoe
    #32
  13. DRjoe

    DRjoe Long timer

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    that was a tank i built for a customer.
    2010(ish) Ktm 450exc

    Was a tricky job because he wanted it to use the stock plastics so i had to make up an airbox lid and right side panel out of aluminium to match the stock ktm plastics.
    #33
  14. kito

    kito Been here awhile

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    Nice work you done there.
    How many litres did it hold?
    Any more photos?
    #34
  15. DRjoe

    DRjoe Long timer

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    If my memory is correct it was 7 litres.
    Ill see if i can find some more photos.
    #35
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  16. DRjoe

    DRjoe Long timer

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    9E8861E3-0D37-4787-84EC-10357868F49F.jpeg E7B65914-DAF6-4C6D-A0D8-B985A293444F.jpeg AC650FF9-D267-4928-B782-DA1D1E75D664.jpeg 01391B95-3576-44B4-B591-E4AD436E40A4.jpeg A77F392D-197C-4639-AB35-3CB9EAA994D5.jpeg 2268DEB2-8E82-4DC4-BB41-CD427CF598D4.jpeg 1315DE0F-9767-43DE-A61C-30F3E7D5EDAA.jpeg C1A802B0-1B2A-450A-A3DA-79AA49C588AB.jpeg The final part was powder coated black.
    #36
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  17. kito

    kito Been here awhile

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    Top quality work that
    #37
  18. DRjoe

    DRjoe Long timer

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    thanks
    #38
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