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Thread: Fuel Filler Mods

  1. #1
    Registered User Emoto's Avatar
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    Fuel Filler Mods

    Similar to the earlier generation R1200GS, the 2013 GS-W has a long filler neck that reaches several inches down into the tank. This long filler neck impedes the rider's ability to quickly fill the tank all the way to the top. Unlike in the earlier generation, the new one is not a soft rubber piece that can be removed with needlenose pliers. I am sure that this long filler neck serves some valid purpose, perhaps even safety-related. For that reason, I do not advocate these modifications and present them for entertainment only. If you do these mods, I accept no responsibility for the consequences.

    The upside of making these mods is that it is easier to fill the gas tank all the way up, which may extend your range somewhat.

    So...

    Remove the 6 bolts from around the fuel filler. I also found it easiest to remove the tank center panel. You can't see them in this picture, but there are a couple of hoses attached under the filler assembly. When you pull up on the filler assembly, those hoses need to move, and I think the tank panel blocks them a little, making it more difficult with the center panel in place.



    It will take a little careful wiggling, but eventually the assembly will pull out. It will not require a lot of force, so exercise caution.



    Grasp the lower filler neck, twist a bit and pull down to separate.

    Note that when you reassemble, the rubber gasket must be positioned so that a hole in the tab on the gasket fits over a red protrusion, and also that the gasket has a tab that fits into a slot on the filler surround. I believe that the hole in the red protrusion is to allow fuel vapor to travel to the canister, but have not verified. My thanks to TBob for pointing out the error in my original post!





    If you want to make the second mod and drill an air relief hole in the part of the filler neck that is not removed, do it before reassembling.

    I recommend using something like a spring-loaded center punch to dimple the plastic in order to provide your drill bit a good start without skating all over when you apply force. About a half inch down, or roughly the same height as the notch tab has been suggested.



    Easy enough to drill a small hole after dimpling. I used a 3/16" bit. Having a shop towel spread out over the tank helps to prevent any debris from falling into the tank. Be sure to clear out the inside of the neck of any lingering drilling debris.



    Then, just bolt it all back to the tank and re-affix the center panel. Remember, those bolts that hold the gas cap and filler neck assembly do not need a lot of torque; be gentle with them.
    Last edited by EMOTO; 09-01-2013 at 09:07 PM.
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  2. #2
    BruceRT
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    Why is the filler neck so long?

    Thanks for showing us these pictures. I was really surprised how far that filler neck extends into the gas tank. I assume it is to ensure an adequately sized air pocket when filling the tank. But why does the air pocket have to be so big?
    Bruce
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  3. #3
    One Man Wolfpack Kent Niederhofer's Avatar
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    Filler Neck

    Vehicle manufacturers design the filler neck in such a way that a sufficiently large air pocket remains after fuel fill up. This allows for expansion due to temperature fluctuation and prevents the tank from "burping" fuel out due to temperature rises. I like filling the tank to the top myself but only to the top as designed. I'm not one to mess with this unless I understand something that the BMW engineering team who designed this doesn't (and that's not likely).

    Kent

  4. #4
    Outlander Omega Man's Avatar
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    Nice job on this Bob
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  5. #5
    Registered User Emoto's Avatar
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    Conceptually identical modifications were made to a lot of prior generation bikes and I have yet to hear of any bad results. Still, it is always less risky to stay with factory standard.
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  6. #6
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    I agree with the fact that previous mods haven't blown up any tanks AFAIK but do be careful about fill levels. Vapor pressures in minium headspaces can get very high in hot sunlight and your gas tank is plastic, If not vented (eg canister removal and plugged lines), there is the chance of a problem. (Ask your wife if she or any of her friends have ever blown up a nail polish bottle left in a car or other hot place).

  7. #7
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    Great job, well done. A word of caution, if you plan to drill, the sparks off the armature of the drill can ignite the fumes. Is the hole really needed? I do plan on doing this and If I think I need to drill I will use a hand drill.

    IBKING

  8. #8
    Registered User Emoto's Avatar
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    Thanks. Neither mod is truly necessary. They simply make it easier to fill up all the way to the top quickly. Try it without drilling, if you care to, and see if you like filling the tank. At least one can easily re-install the removed neck. The hole is just to allow air to bleed out more easily as the tank fills. You may not find it worth doing if you are happy enough without the filler neck.
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  9. #9
    Registered User Emoto's Avatar
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    Please note that I have edited the original post to reflect a correction in how to align the rubber gasket.
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  10. #10
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    Confused

    Does the modification allow additional fuel in the tank or simply faster fill up?

  11. #11
    Registered User Emoto's Avatar
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    Quote Originally Posted by twisty43 View Post
    Does the modification allow additional fuel in the tank or simply faster fill up?
    Hard to say. The way it is stock, you have to keep topping up and topping up and topping up and topping up and... well, you get the idea. So, I think most normal people would run out of patience before they get all the fuel in that the tank can hold. After the mod, you just fill it up.
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