I recently started working on one of the fleet, to make it safely operational. It's been sitting for years. I had help from my friend who owns a shop, and we got it running on an auxiliary gas tank. There was a problem with the bike's gas tank. The ignition key wouldn't turn the 90 degrees needed to open the gas cap. It would turn about 30 degrees, but not what was needed to retract the wide pins securing the gas cap in the fuel tank neck.
If you've ever examined the cap, upside-down, you see the beveled wide pins spaced 180 degrees apart, which retract when the key is turned 90 degrees. The pins on this bike wouldn't retract, when the ignition key was inserted into the gas cap. What to do to try and to remedy this?
I tried carburetor cleaner, sprayed into the lock cylinder keyway. No entry into the gas tank. I tried PB Blaster. No entry. I tried WD-40. No gas cap release. The gas cap would allow that ignition key in the gas cap to turn about 30 degrees, but that was it,
In the past, I had used a sawzall to cut the neck of the OEM gas tank, on another VMax. I cut it just-below the bottom of the gas cap in the tank neck. That allowed me to remove the gas cap, by removing the phillips screws (JIS screws?) on the cap underside, Then I had access to the spring-loaded pins. Off comes the gas cap.
I bought some gas hose which I cut a piece-of to fit over the cut gas tank neck. It 'splices' the cut neck pieces together, and I use a ss hose clamp to do that. I was originally planning on using two ss clamps, but one did the job, and hasn't loosened in use.
Back to the current cap repair. For Plan A, I tried using a 1/4" drive ratchet setup, of extensions and a phillips tip ('the horror, the horror!') and going through the fuel level sender unit oblong hole, to reach the gas tank's screws, While I could see the screws, using a borescope, I wasn't able to securely place the phillips bit into the screws, and then apply enough torque to be able to loosen the screws. I went to Plan B.
For Plan B, I used my Harbor Freight (HFT) portable bandsaw, mounted in the HFT Hercules portable bandsaw tool-holder, to cut a tin can and a beer can in two.
I poured the cut can about 1/2-full of mineral spirits. The neck of the upside-down gas tank went into the cut-up can, to soak the stuck gas cap. To ensure that the gas cap was totally-immersed in mineral spirits, I used a funnel to pour another ~8 fluid ounces through the fuel level sender hole. A few pieces of whatever was handy supported the gas tank. I left it to sit overnight.
The next day, I tried the gas tank key to turn the lock cylinder, the gas cap still wouldn't open. I took the gas tank/stuck cap to a friend's shop, he's a locksmith. I told him what I'd done to that point, and he tried making a spare key and using a pair of pliers to turn the spare key enough to open the gas cap. No luck with that. Then he tried a bump & pick set to open the lock. He called the lock cylinder pins, 'wafers,' because he said that is the proper term if you have a two-sided key (cuts on both key sides). Despite his efforts, he wasn't able to open the lock cylinder. He said he could feel the wafers all moving, but one. He said that wafer was stuck, that it wasn't moving when he was trying to manipulate all the wafers, which he said he was able to feel all wafers moved but that one.
The locksmith told me, when I mentioned I soaked the tank neck upside-down in solvent, "I recommend acetone for that." I informed him I used mineral spirits, and he said that acetone would probably work better. I took my bike gas tank project home, and I did just that. I left it overnight.
The next a.m., I tried the key in the lock, and after a bit of back and forth of the key, the cap popped-off! Great! A minor issue, the paint was lifted off, but isn't that what rattle cans are for?
Note how the detent pins are now stuck in the opened position. That shows how gummed-up the mechanism is. The springs should have pushed-out the detent pins.
Next pic: key removed, and detent pins are back in the 'locked' cap position. Some of the crud (on the towel) is scraped-off the gas cap end. You can see the black paint has lifted off the gas cap. The gas cap screws are not yet removed.
I removed the cap screws, they're pretty-small, they look like #1 phillips, or whatever the equivalent JIS size is. Removing the pieces I made sure to not lose the springs. The die casting to the right containing the wide detent cap retaining pins is the next thing to be removed in the cap disassembly, after the machine screws.
Looking at the gas cap you can see a stamped flat steel piece (the third piece to be removed in a disassembly) which holds the 'top-hat' stamped steel piece with a rubber edge in place. See pic #7 for a shot of that stamped flat steel piece, disassembled.
Above:
The detent pins which slide in and out to latch the gas cap on the gas tank filler neck. The detent pins shown here have not yet been removed from the die-cast piece holding them. Note the two loosely-wound springs for the detent pins, compared to the four more tightly-wound springs beneath the 'top-hat' stamping.
Another view of the cap. The bronze/gold colored stamped-steel disc is the 'top-hat', beneath which are four tight-wound springs (see the next pic).
Four tighter-wound springs are underneath the rubber edged 'top-hat' disc, The spring-loaded 'top-hat' disc is what you feel when you push the gas cap into place (don't forget to align the gas cap neck notch and the arrow of the gas cap) and that's the spring-loaded feel as the gas cap is inserted onto the gas tank neck and it latches closed. You know the gas cap key cannot be removed when the key is in the open position?
The pieces stripped-down to the lock cylinder. From left to right:
The round steel disc with the square hole stamped in it is the first piece removed when the gas cap screws are removed. The rubber-rimmed 'top-hat' stamped steel disc is beneath that on re-assembly. Don't forget the four springs beneath it! The tight-coiled springs are to the right of the gas cap, Three are shown, while the fourth is peeking-out from behind the gas cap. The two widely-spaced coil springs below the machine screws are what push-out the wide detent pins holding the gas cap on the tank filler neck.
The gas cap, disassembled down to exposing the not-removed lock cylinder. It's soaking in acetone.
Above:
The gas cap, with the key in the horizontal 'unlock' position. Note the position of the cap's arrow at 1:00. If the arrow was at 12;00, the key in the open position would be horizontal in relation to the arrow's position.
The next pic, below, showing the 'unlocked' orientation of the die-casting and its D-shaped cast-in pegs, which move the cap's detent pins in and out as the key is turned. The cap arrow is at 12:00 (arrow not shown). Upon re-assembly a schmear of multi-purpose grease, not-much, just-enough to allow the detent pins to slide freely because of the loosely-wound springs which allow the gas cap to lock onto the gas tank neck.
I'm going to take my gas cap to the locksmith, and have him disassemble the lock cylinder to ensure that all the wafers are freely-moving now. That gives me time to paint the gas cap again.
There you have it. If your gas cap lock cylinder doesn't allow the cap to be removed, soak the gas tank neck upside down in lacquer thinner and chances are that cap will come off using the key.
The most time-consuming part of the job is to remove/replace the gas tank. Do a search for Buster Hymen's gas tank removal thread. Never mind, I had an extra minute available.
https://www.vmaxforum.net/threads/how-to-remove-the-gas-tank.9885/
If you've ever examined the cap, upside-down, you see the beveled wide pins spaced 180 degrees apart, which retract when the key is turned 90 degrees. The pins on this bike wouldn't retract, when the ignition key was inserted into the gas cap. What to do to try and to remedy this?
I tried carburetor cleaner, sprayed into the lock cylinder keyway. No entry into the gas tank. I tried PB Blaster. No entry. I tried WD-40. No gas cap release. The gas cap would allow that ignition key in the gas cap to turn about 30 degrees, but that was it,
In the past, I had used a sawzall to cut the neck of the OEM gas tank, on another VMax. I cut it just-below the bottom of the gas cap in the tank neck. That allowed me to remove the gas cap, by removing the phillips screws (JIS screws?) on the cap underside, Then I had access to the spring-loaded pins. Off comes the gas cap.
I bought some gas hose which I cut a piece-of to fit over the cut gas tank neck. It 'splices' the cut neck pieces together, and I use a ss hose clamp to do that. I was originally planning on using two ss clamps, but one did the job, and hasn't loosened in use.
Back to the current cap repair. For Plan A, I tried using a 1/4" drive ratchet setup, of extensions and a phillips tip ('the horror, the horror!') and going through the fuel level sender unit oblong hole, to reach the gas tank's screws, While I could see the screws, using a borescope, I wasn't able to securely place the phillips bit into the screws, and then apply enough torque to be able to loosen the screws. I went to Plan B.
For Plan B, I used my Harbor Freight (HFT) portable bandsaw, mounted in the HFT Hercules portable bandsaw tool-holder, to cut a tin can and a beer can in two.
I poured the cut can about 1/2-full of mineral spirits. The neck of the upside-down gas tank went into the cut-up can, to soak the stuck gas cap. To ensure that the gas cap was totally-immersed in mineral spirits, I used a funnel to pour another ~8 fluid ounces through the fuel level sender hole. A few pieces of whatever was handy supported the gas tank. I left it to sit overnight.
The next day, I tried the gas tank key to turn the lock cylinder, the gas cap still wouldn't open. I took the gas tank/stuck cap to a friend's shop, he's a locksmith. I told him what I'd done to that point, and he tried making a spare key and using a pair of pliers to turn the spare key enough to open the gas cap. No luck with that. Then he tried a bump & pick set to open the lock. He called the lock cylinder pins, 'wafers,' because he said that is the proper term if you have a two-sided key (cuts on both key sides). Despite his efforts, he wasn't able to open the lock cylinder. He said he could feel the wafers all moving, but one. He said that wafer was stuck, that it wasn't moving when he was trying to manipulate all the wafers, which he said he was able to feel all wafers moved but that one.
The locksmith told me, when I mentioned I soaked the tank neck upside-down in solvent, "I recommend acetone for that." I informed him I used mineral spirits, and he said that acetone would probably work better. I took my bike gas tank project home, and I did just that. I left it overnight.
The next a.m., I tried the key in the lock, and after a bit of back and forth of the key, the cap popped-off! Great! A minor issue, the paint was lifted off, but isn't that what rattle cans are for?
Note how the detent pins are now stuck in the opened position. That shows how gummed-up the mechanism is. The springs should have pushed-out the detent pins.
Next pic: key removed, and detent pins are back in the 'locked' cap position. Some of the crud (on the towel) is scraped-off the gas cap end. You can see the black paint has lifted off the gas cap. The gas cap screws are not yet removed.
I removed the cap screws, they're pretty-small, they look like #1 phillips, or whatever the equivalent JIS size is. Removing the pieces I made sure to not lose the springs. The die casting to the right containing the wide detent cap retaining pins is the next thing to be removed in the cap disassembly, after the machine screws.
Looking at the gas cap you can see a stamped flat steel piece (the third piece to be removed in a disassembly) which holds the 'top-hat' stamped steel piece with a rubber edge in place. See pic #7 for a shot of that stamped flat steel piece, disassembled.
Above:
The detent pins which slide in and out to latch the gas cap on the gas tank filler neck. The detent pins shown here have not yet been removed from the die-cast piece holding them. Note the two loosely-wound springs for the detent pins, compared to the four more tightly-wound springs beneath the 'top-hat' stamping.
Another view of the cap. The bronze/gold colored stamped-steel disc is the 'top-hat', beneath which are four tight-wound springs (see the next pic).
Four tighter-wound springs are underneath the rubber edged 'top-hat' disc, The spring-loaded 'top-hat' disc is what you feel when you push the gas cap into place (don't forget to align the gas cap neck notch and the arrow of the gas cap) and that's the spring-loaded feel as the gas cap is inserted onto the gas tank neck and it latches closed. You know the gas cap key cannot be removed when the key is in the open position?
The pieces stripped-down to the lock cylinder. From left to right:
- stamped flat steel piece, w/a square cut-out
- beneath the first piece of flat steel w/the square cut-out, the 'top-hat' piece w/a rubber perimeter
- top right, four tightly-wound springs, which set underneath the 'top-hat' piece. One spring is barely-seen beneath the gas cap
- two phillips/JIS machine screws. They hold the gas cap together
- two loosely-wound screws, which push-out the detent pins holding the lock onto the fuel tank neck
- the cast piece which holds the detent pins, pins are still seen in the die-cast piece
The round steel disc with the square hole stamped in it is the first piece removed when the gas cap screws are removed. The rubber-rimmed 'top-hat' stamped steel disc is beneath that on re-assembly. Don't forget the four springs beneath it! The tight-coiled springs are to the right of the gas cap, Three are shown, while the fourth is peeking-out from behind the gas cap. The two widely-spaced coil springs below the machine screws are what push-out the wide detent pins holding the gas cap on the tank filler neck.
The gas cap, disassembled down to exposing the not-removed lock cylinder. It's soaking in acetone.
Above:
The gas cap, with the key in the horizontal 'unlock' position. Note the position of the cap's arrow at 1:00. If the arrow was at 12;00, the key in the open position would be horizontal in relation to the arrow's position.
The next pic, below, showing the 'unlocked' orientation of the die-casting and its D-shaped cast-in pegs, which move the cap's detent pins in and out as the key is turned. The cap arrow is at 12:00 (arrow not shown). Upon re-assembly a schmear of multi-purpose grease, not-much, just-enough to allow the detent pins to slide freely because of the loosely-wound springs which allow the gas cap to lock onto the gas tank neck.
I'm going to take my gas cap to the locksmith, and have him disassemble the lock cylinder to ensure that all the wafers are freely-moving now. That gives me time to paint the gas cap again.
There you have it. If your gas cap lock cylinder doesn't allow the cap to be removed, soak the gas tank neck upside down in lacquer thinner and chances are that cap will come off using the key.
The most time-consuming part of the job is to remove/replace the gas tank. Do a search for Buster Hymen's gas tank removal thread. Never mind, I had an extra minute available.
https://www.vmaxforum.net/threads/how-to-remove-the-gas-tank.9885/
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