Seat latch won't open

[BlitzenGruv]

Got the BSA back together at last. Time to tend to the '92 K100rs 4V.
I have all the bushings, etc. to do the intake and other stuff. But, I tried to remove the seat today and the latch will not release, the key will not turn in the lock. Guess I'll try some graphite lube on the key tomorrow.
Is there any other way to get the seat open? If I can't remove the seat I can't remove the tank, I can't do the work.
Still haven't found the diagnostic plug. I don't see it in the wiring diagram. I'm hoping that it's under the tank.

[Martin]

What seat have you got, low seat or high seat? If you have the high seat spray the lock, place the bike on the centre stand, get somebody on the seat to bounce gently, and try and unlock the seat.
Regards Martin.

[Laitch]

Got the BSA back together at last. Time to tend to the '92 K100rs 4V.
I tried to remove the seat today and the latch will not release, the key will not turn in the lock.
Still haven't found the diagnostic plug.  I'm hoping that it's under the tank.

It's under the seat but you should be able to get at it by removing a side panel. This is what it looks like on a K75.

As far as opening the seat lock, you must not have owned an old Ford pickup. The stubborn door locks are unlocked like this: Heat up the lock with a hair dryer; spray in the penetrant. Insert the key and wobble it until the lock complies. Adding Martin's persuasion technique might be a plus.

[BlitzenGruv]

It's a Corbin seat. No luck with lube today. Don't know if heat would help, it's been quite temperate here this week. Tried bouncing on the seat too. If it means anything, the helmet lock is open and will not latch.
On the up side, I found the diagnostic plug hiding in front of the battery.

[Martin]

Blitz have you got a low seat or a high seat. My seat lock is in the 10 o/c position when unlocked and in the 2 o/c position when locked. In the 10 o/c position the button has to be pushed in to release the catch. The lock can still be pushed in when in the 2 o/c position but it will not release the seat. Can you push the button in and what position is the lock?
Regards Martin.

[Martin]

Found this might be handy. http://www.k100-forum.com/t4741-dismantling-the-seat-lock#50959   The lock is held in by two bolts with rounded captive heads, the nuts require a 8mm O/E spanner and are accessible. I'm not sure whether if you undo the nuts you could manage to push it in and forward enough to release the seat. The inner rear guard may get in the way and have to be removed. With the side cover removed it is possible to feel the post catch and it should be possible to cut it through with a hacksaw blade but tape up the bits you don't want scratched, you could then just make, repair or buy another post.
Regards Martin.

[BlitzenGruv]

Blitz have you got a low seat or a high seat. My seat lock is in the 10 o/c position when unlocked and in the 2 o/c position when locked. In the 10 o/c position the button has to be pushed in to release the catch. The lock can still be pushed in when in the 2 o/c position but it will not release the seat. Can you push the button in and what position is the lock?
Regards Martin.

High, low, I have no clue. I would guess low, as there's not a whole lot of padding. My lock is straight up 12 o'clock. I can push it in. In past it pushed in and rotated to release. It doesn't rotate now.

[Laitch]

. In past it pushed in and rotated to release. It doesn't rotate now.

Keep on wobbling! :oldguy:

[Martin]

High seat hinges up to the right, low seat completely removable lifts up and off.
Regards Martin.

[Laitch]

High seat hinges up to the right, low seat completely removable lifts up and off.

That's a regular height Corbin in his profile pic, Martin, not a low seat, so it has hinges.

[BlitzenGruv]

Found this might be handy. http://www.k100-forum.com/t4741-dismantling-the-seat-lock#50959   The lock is held in by two bolts with rounded captive heads, the nuts require a 8mm O/E spanner and are accessible. I'm not sure whether if you undo the nuts you could manage to push it in and forward enough to release the seat. The inner rear guard may get in the way and have to be removed. With the side cover removed it is possible to feel the post catch and it should be possible to cut it through with a hacksaw blade but tape up the bits you don't want scratched, you could then just make, repair or buy another post.
Regards Martin.

Jeez! I've rebuilt Lucas handlebar switches, even re-keyed ignition switches, but this looks like a total PITA!
Damn German anal thoroughness. It just a friggin' seat latch, nothing to steal there!

[Martin]

Blitz with the LH side cover removed you should be able to see and feel the lock post catch that goes into the lock, and should be able to cut through with a hacksaw blade. It will be slow and tedious but at least the damage caused by cutting through is easy repairable. I did see another method which involves prying up the seat until the post catch snaps off   :yow Not recommended.
Regards Martin.

[The Mighty Gryphon]

I was just out looking at my bike earlier this evening, and it looks like the lock mechanism is mounted with two machine screws and nuts.  I think they might take an 8mm wrench.  It will take a bit of fiddling, but it looks like if you remove the nuts the lock can be pulled up between the frame and mudguard by lifting the seat and at the same time pushing the lock back away from the frame.  It will be a tight fit, but I think it can be done. 

From there you can remove the post from the bottom of the seat and work on the whole mess at the comfort of your bench or maybe take it to a locksmith.

Finally, I am assuming all your locks are keyed alike.  If so, you may have a worn out key and this is the first lock to give you trouble.  If that is the case, it may be a good idea to get a new key before another lock stops working with it.  OEM keys are hard steel, but hardware store keys are brass or some other soft metal.  You may have a soft replacement key that is wearing out and possibly wasn't cut perfectly to begin with. 

[Martin]

Found this might be handy. http://www.k100-forum.com/t4741-dismantling-the-seat-lock#50959   The lock is held in by two bolts with rounded captive heads, the nuts require a 8mm O/E spanner and are accessible. I'm not sure whether if you undo the nuts you could manage to push it in and forward enough to release the seat. The inner rear guard may get in the way and have to be removed. With the side cover removed it is possible to feel the post catch and it should be possible to cut it through with a hacksaw blade but tape up the bits you don't want scratched, you could then just make, repair or buy another post.
Regards Martin.

Gryph I also had a look at that and it would be a close call might have more room if he loosened the inner guard. I also had a look for an alternative and I managed to get a hacksaw blade in but I would try to remove it first. Then try cutting it I would not go the prying up of the seat as I found elsewhere seems rather drastic.
Regards Martin

[Laitch]

I second Gryph's  suggestion of trying a different key. Be patient and keep wobbling that key. It should comply. It doesn't matter if the helmet lock is open. That's activated by rotation in the opposite direction.

[BlitzenGruv]

Thanks,
My key is the original steel. Hate to think what the dealer charges to make a copy, but a new key might be the answer.
I can see two allen bolts where the seat latch mounts to the seat pan. I might be able to get them out and remove the seat that way.

[Martin]

 :2thumbup:  Where there's a will there's a way never give up never surrender.
Regards Martin.

[Laitch]

It just a friggin' seat latch, nothing to steal there!

Except the battery, the electronic control unit and whatever tools are beneath it. :giggles  But who'd do that?

I'm with Martin. Don't give up! Don't surrender! Keep on wobbling!