Seat latch mod for no key

[Charlie-brm]

My bike came with 2 of 3 keys needed for ignition, fuel cap and seat/helmet lock. The seat was missing the hook on the right side because to have it in place would permanently lock down the seat, the key being AWOL.
Another FJOwner donated 2 hooks to me this week so I at least got the issue of a sloppy seat sorted out until such time as I meet up with a locksmith. Here's how:

1984 FJ1100
remove the seat
remove the right long side panel
remove the grab bar, 2 12mm bolts
remove the 10mm bolt securing the forward end of the plastic tail section. It would have been partially blocked by the grab bar
remove the 2 phillips screws holding the latch mechanism to the frame
ease the tail section plastic out and drop the mechanism free.

Disassemble the mechanism on a clear table, laying it flat. There are 3 compression springs inside, the 2 bigger ones waiting to whiz by your ear given half the chance. Don't ask how I know.
Remove the 2 small phillips screws holding the back plate.
Ease up the plate and keep an eye on the ball and spring in the center disc at 12 o'clock. Put them aside to be replaced
Try to keep the top spring and sliding block in place, or pull the spring to preempt it getting airborne on its own.
Remove the spring and block at the lower left. Store these for the future when you have the lock and key sorted out and can put the mechanism back to normal.
They won't fit back in when the center disc is rotated 180 degrees, which is the next step.


Lift out the center disc and replace it on the shaft 180 degrees offset, so the ball and spring cavity is now at 6 o'clock instead of 12 o'clock.
The release lever will now operate independently of the lock to engage and release the seat hook. The helmet hook will be inoperable with this mod.
We're going to leave it in the closed position.
Where the spring and block were in the lower left, drop in a hex nut with a snug fit. This will block a small pin that keeps the helmet hook in the closed position.
Reassemble the mechanism, with the ball and spring in the center disc.
Screw down the back plate, adjusting the screw tightness as necessary so the lever operates freely without binding in the up or down position.
Bench test the mechanism is working with a hook unbolted from the seat if you want to check it before attaching to the bike.
Attach the mechanism back on the bike's frame and bolt up the tail section and grab bar.
Replace the right side panel.

Total time is maybe a half hour without trying to win any medals.
Both photos show the center disc in the final rotated position
The second photo shows the spring and block to save for later, set aside from the rest of the mechanism.

[FJ_Hooligan]

Not sure I followed all of that, but if you can get the key cylinder out you should be able to pull all the wafers/pins out to disable the locking function.

Doing this, any key (or screwdriver) will activate the mechanism and you will retain the helmet lock.

Hooligan

[rktmanfj]

FWIW, I was surprised to find that after installing my new ignition switch, my new key worked both the seat latch and gas cap.