I wasn't sure whether to add this to the thread about the switch part of the ignition and decided to do a new thread. Since I had my OEM ignition lock apart for servicing the electrics, I got the itch to open the lock and see what's going on in there. You know, take it apart, clean it, new lube, etc. I almost blew it, but I got it all back together and boy oh boy is it smooth. Like the electrics, there are certain keys that only go in one way. Note them and take pictures to aid reassembly. You can use this information to drop a new lock on the body, fix something that's not right, re-key your lock, or maybe even create a custom key by moving the tumblers around. Maybe. I'm not a locksmith but it looks possible.
Also note that the newer style doesn't have a set screw holding it together. I'm guessing they slid things in place and dimpled the cover to call it done. This lock is from a '76 CB550F.
The first step is to remove the set screw and remove the polished cover. There are dimples and the punch mark from the set screw that will drag. I twisted and lifted and it came off.
The bolt that locks the fork is spring loaded, so move it in and out a bit and the ring and the lock shaft will slide out. The fork bolt won't because it's kept in by the panel on the back (that I did not attempt to remove.) I cleaned it all up with CRC electronics cleaner because the lock cylinder is plastic and it's what I had out. I put some silicone paste on the sliding parts and reassembled it.
The lock mechanism is pretty simple, but you gotta be careful not to lose parts - I almost lost a tiny spring from the lock cylinder. You need to slide the cover off the lock mechanism, and while it's off, pop it into the lathe for a quick polishing.
The plastic lock cylinder won't come out of the aluminum housing until you put the key in. Before you do this, mark the spot where the horizontal pin is aiming so you know where to orient things when reassembling. I just did a scratch mark. Here the pin is already out, but you can see the mounting hole.
Keep the key in place and slide the plastic cylinder out. Don't take the key out yet or you might lose the lock tumblers (wafer tumblers, I believe.)
If you want to check each tumbler, you can slowly remove the key, but keep the side with the hole for each slot up. There is a spring in each that keeps the tumblers against the lock housing when the key is out. A couple of mine had corrosion that I cleaned up. And don't take more than one out at a time. They must be in order, or your key no longer works. See why I said you could re-key this one if you wanted? If you only want to clean it, leave the key in so the parts can't escape and spray with your choice of plastic-safe cleaner. The round tab on the side goes pointing down and against the spring.
As I started to reassemble things, I realized that the spring-loaded door was bent and not closing fully. Since it looked pretty simple, I decided to remove the cover. Just bend the tangs with a small screwdriver and pry it off. Do be careful not to loose the door, the shaft or the tiny spring. Blue tape keeps the tumblers in place while the key is out. I scraped out dirt and dry lube, and carefully bent the door flat. It's a little tricky to get the cover on while the door stays in place, but it works to put the cover over a screwdriver that holds the door wide-open. Then slide the cover in place.
Reassembly is the reverse. I hate that sort of instruction, but it's true. There are certain parts that are keyed that take the guesswork out of things, but it can be confusing if you don't make marks or take pictures.
One reassembly clue is the ring in the mount has a key you can see at the 4:00 position. It needs to fit into the corresponding part of the lock cylinder, but if the fork bolt has popped out, you'll need to push it back in before you slip the cylinder in place.
The key goes into the slot in this shot that's at the 7:00 position (this is a shot from when I took it apart and it was still uncleaned.) Also note the spring in the end of the plastic lock cylinder. Don't lose it.
Functionality checks are making sure the key goes in/out easily, the lock turns only 90* between OFF and P, 90* between OFF and LOCK, and only keeps the key captured in the ON position.
I still need to finish the electrical part, but the lock works like new and looks pretty good. I thought about having the metal housing vapor blasted while it was apart, but nah.. Everything you probably never cared about your lock mechanism and how it works.
