Gas tank hose not connected; repercussions?

Discussion in 'GS Boxers' started by 1200gsceej, Oct 5, 2012.

  1. 1200gsceej

    1200gsceej Long timer

    Joined:
    Apr 30, 2007
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    1,438
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    San Francisco Peninsula
    I was working on the bike and took off the right side cover to get better access under the beak. What I found was that one of the 'hoses' was not attached to the gas tank.

    In the attached picture below, it was the one on the far right, marked in pink. There is a "W" etched in the plastic under the pink spot.

    I ought to know this by now, but ...
    Can someone tell me what the two right hoses are for?
    And what happened (or did not happen) while the far right one was not attached?

    Now I'll have to figure out whether I was the last one to remove the tank, or if the BMW shop was the one? I don't imagine that vibration should shake them loose if they were properly attached.

    Thanks,
    -ceej


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    #1
  2. Girthy Knobkers

    Girthy Knobkers Running on reserve

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    I believe one is overflow and one is for charcoal canister... any overflow would not drip onto the ground, instead under your tank which could potentially cause a fire...?
    #2
  3. roger 04 rt

    roger 04 rt Long timer

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    You've got it correct. One hose drains water from the outside of the tank in the filler neck area. The other hose vents the inside of the tank through the charcoal canister. That hose is connected to a one-way valve that keeps fuel from running out if the bike tips over.

    I don't know which hose is which on your bike. If it is water drain, nothing bad happens. If it is the vent, if you left it open a long time, dirt might get inside and (heaven forbid it) vapors would escape into the atmosphere.
    #3
  4. TUCKERS

    TUCKERS the famous james

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    The only danger is dripping gas.

    After doing a canisterectomy I connect both of these hoses together up there with a Y pipe and just drop one hose down to a safe place. The best place seems to be next to your rear brake master cyclinder with enough hose hanging down that any spills don't touch anything.

    As it is now if your bike falls over when it is hot or running, or if you over fill your gas tank when hot....gasoline could drip on the engine and cause a fire.
    #4
  5. slartidbartfast

    slartidbartfast Love those blue pipes

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    Using a Y-pipe seems like a simple way to eliminate a hose - but if the end of the hose gets plugged (mud, wasp's nest, etc.) it would direct accumulated rain water under the filler cap straight into the tank. That would ruin your day and you might have the tank apart for filter change a couple of times before you figured it out.
    #5
  6. TUCKERS

    TUCKERS the famous james

    Joined:
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    yep. there's a lot of 'if's' in life
    #6