GAS CAP WON'T UNLOCK

On my 83 Yamaha FJ1200, it has the aviation type fuel cap where you unlock the cap with the ignition key and the hinged cap swings up to expose the fuel opening. Well, my key goes easily into the lock and turns about a quarter turn, but then stops and will not unlock the cap. I've sprayed various lubs and break free sprays into the key hole with no luck. I've tapped on the cap with a rubber mallet, tapped on the key with the rubber mallet as I tried to turn the key, but no luck. I don't know if the problem is in the lock itself or in the locking mechanism where maybe the locking bar has stuck from gummed gas, rust, or who knows what. Does anybody have any ideas what else I could try before I ruin the lock by drilling it out? Thanks

Have you tried pushing down and then trying to open that should relieve some
of the tension on the locking tab.

I'd visit a locksmith before trying the drill. Keep squirting solvents into it. Maybe PB Blaster. Try to spray some under the edges of the cap, and down the keyhole. Be gentle with the key. Patience and constant fidgiting of the mechanism combined with solvent will probably get it loose.

If not, take the tank off and take it to a locksmith.

HiSPL said:

I'd visit a locksmith before trying the drill.

If not, take the tank off and take it to a locksmith.

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He will have to take the bike to a locksmith, if the penatrating oils and slowly working the lock do not work as most of these caps that are held on to the tank with allen bolts still will not come off even if you remove all the allen bolts holding the retaining ring down as the lock mechanism fits into the neck of the tank so it is still locked in place after you remove the allens

I've got some of these locks. '81/'82/'83/ The lock tabs can jamb,
I don't know how to send pix in this forum, but if you call/text me @512-565-4031, I'll send you pix of the internals of one so you know what your dealing with. The two locking ligs slide against each other, and the key has 2 round fingers that move the lugs. Thyere's enough points of friction to stop a freight train!
Looking at the pieces, you need to put CARB CLEANER FIRST, then LIGHT OIL- 3-in-1 or Liquid wrench into the key tumblers while moving the lock cylinder in/out to pump the lube down to the lugs. The lugs are pot metal, and old gas sludge can gum them.

I have a 1981 Yamaha SR185 that sounds like it has a similar gas cap. The cap was stuck on that bike because when I parked it, I didn't drain the fuel (at the time, I thought I would be working on it every day or so, but didn't) so the "wings" as I call them got stuck. The key would turn the full distance, but the internal wings that lock inside the gas tank were stuck hard in place.

I actually tried many things to loosen it up over the course of a month and got no where. I found a new gas cap off Amazon for a newer Vstar 250 that is almost identical so I was able to use that as a replacement.

To get the old cap out, I basically took any piece off the cap I could. I started with the shinny outer piece and pried it loose. After getting that off, i realized I coulnd't get any PB Blaster (or anything else) in there to loosen it up. I ended up using a flat head screw driver and force to pry the cap out. Doing this slightly dented the tank, but I hardly notice it.

From that experience, I would recommend you try turning the tank upside down, then try the carb cleaner (or something else) that you can put a fair amount into the tank from the petcock area. Then shake it (or whatever) so you can actually get the cleaner stuff on the wings of the gas cap.

I don't think any amount of cleaner in the key part will do any good as that is supposed to be able to get wet in the rain and not spoil the gas.

Good luck

the cap on my ZRX does that and it is the lock pin that binds, spraying stuff in from the outside does not get to it.

here is what I do:

key fully in, push down on cap and apply moderate turning pressure on the key. take a small but solid object ( I use a closed leatherman multi tool) and knock on the cap repetably. the cap should pop loose.

I believe the fj has a fuel level sensor, you might be able to remove the tank from the bike, stand it up vertically, remove the fuel level sensor from underneath the tank (usually 4 bolts) and then use the hole to access the locking mechanism from inside the tank. Hopefully you can push the locking bar inside the fuel cap, and open the cap. Then you can remove it from the bike and find out what is wrong. Put the fuel level sensor back in (I would suggest using a new gasket) and put the tank back on the bike whilst you fix the cap. Drilling the lock should be your very last resort, well drilling and dynamite should be the last resort..

Gary

Well??

retcol took a fall off a ladder onto concrete shortly before Christmas. Fortunately no major injuries, but broken ribs, fractures, major bruising, etc. So looks like he'll be healing up for a couple of months before tackling this project.

Ouch, I hope he heals quickly, I hate broken ribs, they hurt for a long time.. not a great way to start the new year, hopefully things will only get better for him.

Gary