Topic: Can the seat lock be repaired?

[Scott S]

 ** This is for my CL350, but it uses the same seat lock assembly as the SOHC4 so I thought I'd throw it out here**

 Can the lock be repaired?
 Just found out the the lock/tumbler on my '73 CL350 is busted. There appears to be a ring or cam of some sort that moves with the key/tumbler and is supposed to release the plunger. Mine's in about four pieces.

I see that 4into1.com has a matching ignition switch and seat latch set for about $30, or just the seat lock for about $20.
Is it even worth trying to find a used lock to repair mine? Or replace it and most likely have mismatched keys?

Anyone ever repair the lock mechanism on the seat latch?

[madmtnmotors]

I will often remove the brass "pins" from inside the lock. This turns the seat lock into a simple latch that looks like a lock, similar to the later (77/78 CB750) fuel door latch. Not sure if the pieces you would need to retain are the parts that are broken though.

[Scott S]

 I'll fiddle with it later and get some pics. I didn't discover this until late last night and didn't really dig into it.
 So you're saying that the latch will hold and open and close with a key but won't truly be locked?

[madmtnmotors]

So you're saying that the latch will hold and open and close with a key but won't truly be locked?

Yes. I am most familiar with the seat locks on the later 77/78 models, and they are pretty simple assemblies. The ones I have worked on use a single circlip to hold the whole thing together (once the assembly is removed from the frame). The latch pin and spring are removed, then the circlip, then the lock drum is removed from its bore. The little brass tabs and tiny springs are removed and the rest is reassembled. The latch pin and spring are driven by the turning key drum making the latch and lock two different (but linked) components. I may be able to post some picts this evening as well.

[wowbagger]

I tried taking my 1972 CB500 locks to an old school locksmith in town to see if he could re-key them to use one key (3 keys for one bike seemed excessive). Unfortunately, he claimed that these old locks were press fit and not intended to be worked on. He said he could open them but there was no way to get parts for them. He may have been saying all of this just to get out of having to work on them but he's never shied away from anything else that I brought him, including hand bending new springs for old cast iron mortise locks.

Sounds like removing the pins from the tumbler may be the best option short of replacing it.

[Scott S]

 I don't think removing the tumblers does any good when this ring is broken. Looks like I'll just be looking for a replacement latch.

[wowbagger]

Oh, that makes more sense. Yeah, that's good and pooched. I think I have a spare seat latch in a box somewhere. PM me your address and I'll send it to you once I find it.

[Scott S]

 I see the circlip you're talking about.....can it be disassembled in order to swap out that "cam" part that's broken on mine?
 PM incoming....

[madmtnmotors]

I see the circlip you're talking about.....can it be disassembled in order to swap out that "cam" part that's broken on mine?
 PM incoming....

Actually, you do not have to remove the circlip at all. The "cam" part is the only part you need to replace. This provides the link between the "lock" and the "latch". This cam just slips into place into the notch on the latch pin. The latch pin, cam, and latch spring are "captured" when the latch is bolted back on to the frame. All you need to do is harvest a cam from a donor latch and you can leave the key tumbler as is if you like, especially if it still matches the ignition lock. The cam has a square hole that fits over the square end of the lock cylinder and a pin that fits under the cutout on the latch pin.

[madmtnmotors]

Sounds like removing the pins from the tumbler may be the best option short of replacing it.

I often do this when replacing the ignition, since the new ignition key would no longer match the seat lock. 

[Scott S]

 Well, dang it! I found a lock assembly in my stash and disassembled it only to find that the tumbler and cam are completely different. The cam won't fit the old tumbler (and I've now removed the pins) and the key won't fit the later tumbler, even with the pins removed (completely different style of pins). Now I have TWO worthless seat latches!
 Oh well....that set from 4into1 is looking like a mighty good value right about now....

[madmtnmotors]

Yeah, that early style looks just enough different to prevent interchanging parts. Looks like the later lock cylinder is too large to fit the bore in the early latch as well. Surprised the key doesn't fit though, with the tumblers removed it's just an empty slot.

You do see the simplicity of the mechanism now though. 

[Scott S]

 On the later style, it's not an empty slot. There's a key way in there. But, yeah....I see how you can remove the brass pins and just use it as a latch and not a lock.

[drumstyx]

If we're talking about key wafers, you should know you can swap em around to match different keys. Mine only has 3/5 wafers because the other 2 didn't match, but it's now a working rekeyed lock.

[Scott S]

 The later style had wafers, for lack of a better term. The earlier lock had three brass pins. They're totally different. I would have been OK with just a latch, since there's nothing really under the seat of a CL350 to steal other than the battery.

[754]

Honda uses several key styles, if you show a pic of the entry point for the key, might be someone has a key..