This may have been posted by others but here goes.
My 89 came with separate keys for tank, seat and ignition. I cannot live with that. Too many keys.
I saw here, somebody removed the tumblers from seat and tank for single key solution, the ignition key operates all. Wonderful. It works. I did that today.
My humble contribution is to say, the tank lock is trickier, depress the brass slide plate on the back inside side of the tumbler, with the key not being in the hole and it falls apart into your hand. Use a cheap jewelers screwdriver, ground down to reach in. This is last step of disassembly before removing the tumblers, the tiny spring loaded brass stampings, which slide out sideways with gravity.
Then reassemble in reverse order per Clymer narrative logic.
3 keys ??? You know they don't call it suzukey for nothing right. 3 key minimum.
Kawasakey should have 4 keys, but Honda and Yamaha - who knows what a ha is - but you need many many HA's on a Yamaha.
Cool.
Buddha.