How to remove a jammed gas cap

Discussion in 'How To Guides' started by Fire-medic, Aug 19, 2019.

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  1. Aug 19, 2019 #1

    Fire-medic

    Fire-medic

    Fire-medic

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    Have you ever-had a gas cap refuse to come-off? Sometimes the cap will become so-rusted/gummed-up that it will not allow the retractable wedges to retract, releasing the cap. This is one way to do it, it doesn't cost-much, and you get-back your normal tank function. It does require a bit of work. Have you priced a gas cap from your local Yamaha dealer? Ron Ayres Motorsports: gas cap $115.49, fuel tank, $297.49; partzilla: gas cap $108.45, fuel tank: $297.37, so this is well-worth the sweat equity.

    Someone will say, "just take it to a locksmith, and have them pick it!" The problem is that the mechanism is frozen due-to gum and/or corrosion, and a simple 'bump' to open the locked cap isn't possible.

    Remove the gas tank. There is a 'how-to' for the procedure, I have not found it necessary to remove the swingarm, some methods mention doing that.

    Measure down 5/8 inch from the top of the filler neck, wrap masking tape around the filler neck, to guide you in cutting off the filler neck, with the gas cap in-place. You can use a Dremel and a cutoff wheel, or a sawzall, I prefer the Dremel or other abrasive disc tool. Of course, do this with an empty gas tank! Draining the gas through the hex bolt drain port on the bottom of the tank is one way, or remove the gas level sending unit. After emptying the tank, use water to rinse the tank, and then use compressed air to dry it thoroughly. Then you can cut the neck with the Dremel cut-off wheel and mandrel, remember that 5/8 inch dimension.

    The 5/8 inch will put your cut below the gas cap.

    Once the neck has been removed, you can disassemble the gas cap by removing the two phillips-screws. There is a 'how-to' on refurbishing the gas cap, follow it.

    At your friendly NAPA store, buy a 2" I.D. rubber gas hose, used for the filler neck on a 'cage' (car or truck). You will probably need to buy a foot, but you only need an inch. You could go to a wrecking yard and look for the correct size, or you could use a length of vehicle water hose, but the first is time-consuming, and the second probably isn't rated for use as gas tubing.

    Use a file or your Dremel and and a drum-shaped abrasive stone to remove the sharp edges on the filler neck and the piece you cut-off. Make sure the notch on the cut-off piece of the filler neck faces forward.

    Put the 1 inch piece of 2 inch i.d. gas hose tubing (NAPA part NBH 1045, gas filler hose, it doesn't have a steel helix in it (metal wire-reinforced), just rubber and some-type of heavy thread, probably cotton, so it's easy to cut. Do not buy the super-stiff metal wire-reinforced rubber gas hose! It is much too-stiff to make this repair!) over the filler neck on the gas tank. Put the cut piece of gas tank filler neck into the other end of the 2 inch gas hose tubing. You want to position the 1 inch piece of gas hose tubing where the middle of the gas hose rubber tubing covers the two pieces of the steel filler neck. Start to tighten the hose clamp (NAPA BK 705-1216), use the type of SS hose clamp which doesn't have the exposed serrations which can dig-into the hose rubber, and cut it. The rubber hose closest-to the gas cap should be about 1/4 inch-3/8 inch below the bottom of the gas cap.

    This is where I use some safety wire to secure the loose end of the hose clamp. You won't tighten the safety wire until the hose clamp is tight, and neither the gas tank neck, nor the piece of the neck you cut-off, is moving-around. Then use the safety wire to secure the loose end of the hose clamp.

    That's it, you can now replace the gas cap. Try it out for operation, it should easily release.

    Sure, if you have the tool, you could TIG weld the cut-off gas tank neck back onto the gas tank filler neck. This is for those who don't have access to that.

    If you use a Corbin seat, you can use a longer hose and put the gas cap closer to the surface of the seat. This is especially useful if you have the older Corbin 'flap' style seat, instead of the 'plug' style. You will need two clamps.

    VMax gas tank neck.01.jpeg VMax gas tank neck.02.jpeg VMax gas tank.03.jpeg VMax gas tank.04.jpeg
     
    Last edited: Aug 20, 2019
  2. Aug 19, 2019 #2

    one2dmax

    one2dmax

    one2dmax

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    Or, I think if I remember you can reach into the tank from the bottom side through the hole where the sending unit is and depress the locking tabs and push it off
     
  3. Aug 20, 2019 #3

    Fire-medic

    Fire-medic

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    one2dmax said:
    I think if I remember you can reach into the tank from the bottom side through the hole where the sending unit is and depress the locking tabs and push it off

    Sean, if only it was that-easy! Take a cap off the bike, make sure the key isn't in it, that the mechanism is as it would be, in the latched position and try to push those tabs. They don't retract! That's the problem, that the closed-position cap, if it's gummed-up, or rusted in-place, will not physically-allow the locking tabs to retract, even-if you have a key. I've found this type of problem in buying neglected, used bikes.

    I also considered that you might be able to remove the gas tank, invert it, and soak the tank neck and stuck cap in some-type of solvent. Acetone, mineral spirits, lacquer thinner come to-mind. The acetone and lacquer thinner would probably remove the paint from the gas tank neck and the gas cap, requiring a re-spray.

    Another way to try to do it would be to find the world's longest shaft phillips screwdriver, and to remove the screws in the underside of the gas cap, letting the latch mechanism, the cams, the locking tabs, springs, etc fall-off, and then remove the cap. What wouldn't fit through the gas tank sender unit opening: a really-long 1/4" square drive socket extension and a phillips-bit.
     
    Last edited: Aug 20, 2019
  4. Aug 20, 2019 #4

    Fire-medic

    Fire-medic

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    VMax gas cap detents - Edited.jpg I just tried to use a blade screwdriver to retract the gas cap detents. No-matter how hard I pried, I couldn't get the detents to slip-past the rolled sheet metal lip of the gas tank filler neck.

    Proof of not being able to pry inwards the gas cap detents can be seen in how you replace the gas cap. If you leave your key in the gas cap, sometimes you can just align the gas cap immovable indexing tab, and then push onto the filler neck, the gas cap. This is possible because with the gas cap key in the key cylinder, and the key cylinder is not in the fully-locked position, the detents are able to retract inwards.

    However, when you turn the key fully to the left, which you need to-do to remove the key, the detents will not be able to retract sufficiently to allow you just push-onto the gas tank filler neck, the gas cap.

    This is all empirical data from experimenting on my gas tank system. As is often said, "your results may vary." You can contribute to the thread.

    I also posted pics of the gas cap filler neck cut-off line, if you use my recommended 5/8" dimension, the 1" rubber hose dimension for the 2" i.d. rubber hose piece (NAPA part NBH 1045, gas filler hose), and the NAPA BK 705-1216 SS hose clamp, which has an inner smooth surface preventing the worm-drive slots in the SS band from cutting-into the 2" i.d. rubber hose. I suggest using a 9/32" dimension from the top lip of the gas cap filler neck end, to the top of the 2" i.d. rubber hose. You can see this leaves a decent gap between the gas cap and the 2" rubber tube/SS clamp, providing good clamping for the SS clamp, and easy removal of the unlocked gas cap. What you want to be sure-of, is that the SS hose clamp has a good 'purchase' on both the gas cap filler neck, and the piece which you removed from it, onto-which the gas cap is affixed.

    Using these dimensions, I'm able-to pick-up the empty gas tank by the rolled-lip of the filler neck (the piece you cut-off the tank filler neck), and I can shake the entire tank up and down, without having the SS clamp holding things together, loosen, and fall-off. You could always weld it back together if you had the equipment, as I already mentioned. VMax gas filler neck cut line.jpeg VMax gas filler neck clamp.jpeg VMax gas cap detents.jpeg
     
    Last edited: Aug 20, 2019
  5. Aug 20, 2019 #5

    Pighuntingpuppy

    Pighuntingpuppy

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    Instead of rubber with a clamp, what say you to welding? Cleaner look I would think. Your method though would be great in case the cap ever gummed up again. Just pop off the whole unit.
     
  6. Aug 20, 2019 #6

    Fire-medic

    Fire-medic

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    Yes, I mentioned the option of welding, twice. I have a multi-process 240 V welder where I could easily have done the weld repair. As you observed, if you ever ended-up in that type of a circumstance (corroded, gummed-up gas cap lock cylinder) subsequently, it would be very easy to access the cap underside and the tank itself.

    You could also find another unkeyed gas cap and neck in a 2" o.d. and use that instead, forever solving the issue. Has anyone ever had their gas tank on a motorcycle tampered-with (possible exception for psychotic ex-girlfriends)?
     
  7. Aug 20, 2019 #7

    Pighuntingpuppy

    Pighuntingpuppy

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    I read slower this time, LOL, I saw it. Was going over the more pertinent details of your post. Still a great topic. I think this could be made a sticky for a how to. Lots of good info. Maybe follow it up on what you would do to weld to cover all bases.
     
  8. Aug 20, 2019 #8

    Fire-medic

    Fire-medic

    Fire-medic

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    The people who would choose to weld probably weld better than I do. If you use flux wire-feed, I'd wrap the tank except for the neck in a welding blanket to prevent putting splatter all-over the outside of the tank. Probably TIG is best, spot two or three equidistant places on shiny bare metal, then go-back and fill the points between, don't be in too-much of a hurry, give it time to cool-down a bit so the metal doesn't warp. You could braze it too, if you're good with the flame tip and puddling, on a cleaned, no-paint surface.
     
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