How to "rekey" K bike locks

[frankenduck]

3/29/12: Printable PDF version attached below.

This is handy if you replace the gas cap, seat lock or luggage and want to rekey them so they work with your ignition key.

Here's a K bike lock core. (from a system case lock.) They are all basically the same with respect to how they work.  They have six metal slats on springs in them.  Since we're dealing with locks, I'll call them the "tumblers."  The last tumbler is what holds the lock core in the lock. I call it the retainer tang.

MODIFYING LOCK CORES:  What you do to make the lock work with a particular key is to insert your key and then file down (I use a Dremel grinding wheel) anything that sticks out.  Here's a lock core from a 35L top case:

Insert the "new" key and then file down anything thing sticking out:

REMOVING LOCK CORES

System Cases or City Cases:  Turn the key to the open position, open the lock, turn the key to the locked position and then use a 3mm or 4mm Allen wrench at the back of the lock core to depress the retainer tang.  Then slowly wiggle the lock core out:

22 Liter Top Case: I don't have a picture handy but first remove the lock from the case by removing the large hex nut that holds the lock in place.  You'll see a small hole in the side of the lock that is located above the retainer tang. Turn the key so it's facing that and then insert a sewing needle, dental pick or other slim metal object into that hole to depress the retainer tang. Then wiggle the lock core out.

35 Liter Top Case:  There are some Phillips screws the hold the handle and lock assembly on the inside of the back of the case.

Gas Cap:  I recommend doing this off of the bike so parts don't fall into the tank.  The gas cap is removed by unscrewing the four countersunk Phillips screws you see around the perimeter when the gas cap is open.  Since they are mounted in aluminum the dissimilar metals can cause corrosion in the threads.  Therefore you need to be careful removing them or you can strip the heads of the Phillips screws.  First clean out the heads with a dental pic or something so that you can get a Phillips screwdriver all of the way in.  Then, using your best fitting/best quality Phillips screwdriver apply a lot of downward pressure while intitally turning the screw to break it free.

Once you have the gas cap off of the bike remove the three Phillips screws that hold the lock assembly to the gas cap.

Then use a screwdriver or whatever to depress the retainer tang and remove the lock core:

Putting the gas cap back together can be a little tricky installing the cup and return spring properly.  Start by putting the return spring in with the part sticking out at a right angle positioned in it's grove in the lock housing:

Then put the "cup" on so that the groove on the bottom of it sits on the center straight part of the spring:

Applying constant downward pressure, slowly turn the cup counterclockwise until you feel it drop into place:

Then carefully reattach the assembly to the gas cap with the three Phillips screws.


Seat Lock: Remove the seat lock from the frame by unscrewing the two 8mm nuts on the back of it and the two small Phillips screws from the front.  Use some small screwdrivers to break the face plate off of the rear housing. It will look like this:

(Hopefully your seat lock hook isn't busted off like this one.  It's just an old one I'm using for demo purposes here.)

Pop the latching bars out of their pivot and then you can remove the lock.  Use a dental pick or sewing needle to depress the retainer tang and remove the lock core:

Once you've modified the lock core, glue it back together with some epoxy or JB Weld around the outer edge.  One nice thing about the design of the seat lock is the the two bolts at the bottom that attach it to the frame help hold it together.

Footnote: If you're a purist with respect to locks then you can play around with swapping the tumblers but I just want my key to work so the filing down method works for me.  Also, if somebody REALLY wants to steal from my bike then they'll just break their way in.  Locks just slow thieves down or deter the lazy ones.

edit by scott_ 10-13-13 to update missing photo's

[johnny]

[joepopp]

Frankenduck and Johnny: Thank you so much for this thread. You saved me a ton of time and money!  :2thumbup:

I had trouble getting the 22 Liter top case cylinder out and I found another thread. It seems I had to rotate it 180 degrees counterclockwise.

- Rotate the large nut inside the case counterclockwise looking at it, fiddle it off and fiddle the lock out.
- Looking at the hook end of the lock, on the right side just at the beginning of the threaded area, there is a small circular flat area with a hole in the center.
- Make sure the lock is in the "unlocked" position.
- Use a 1/16 inch diameter rod (Allen wrenches will work fine.) and shove it in ~3/8 to 7/16 of an inch into the hole. This depresses the lock retaining tab (extra "tumbler").
- Using the key, rotate the lock 180 degrees, 1/2 turn, counter clockwise. This positions the retaining tab in a slot where it can be removed.
- Pull the lock cylinder out. This does not require major amounts of force.

Here is the whole thread
http://www.ibmwr.org/otech/topcase.html

[billday]

Well done as always, Duck.

I just bought a "new" pair of system cases from a guy I met here on Motobrick.... He shipped the cases with a key.... completely by accident I discovered that my bike's ignition key works the cases' locks better than the key that came with the cases.

In this type of lock, what you call a tumbler is called a wafer. (Former locksmith, showing off.)

[Qdude]

Brilliant anyhow Duck, Jargon notwithstanding.

Those wafers whose tabs extend beneath the key (under the straight/flat side/part of the "keyed" section of the key) are not being lifted up high enough due to the cut in the key being too deep. Dremel those ones down (or up actually).

But for the ones that extend up above the key (over the bumps and valleys of the cut part of the key) they are riding over a key cut that is too high. Those wafers may have the aperture inside the key channel cut taller (i.e. deeper), thereby lowering the wafer and its upward extending tab, bringing it down to "shear" (more Jargon for you from another show off Smithy, a shear cylinder is smooth and will turn)

This would increase the "overall degree of security" of the lock in that there would be fewer key combinations that would "unlock" it. The wafers are designed so that one key cut depth holds the wafer centered so that its upper and lower tab are both in shear. If it is raised too high (or not high enough) and the tab is filed down, then you are adding about two more key depth possibilities per millimeter removed. In the bigger picture, who f'ing cares. I think the method you have developed is genuinely genius. But if you would like to take it up a notch you consummate craftsman...

Pull the wafers out of the cylinder straight in the direction that the spring is pushing, and yes the spring is in that alternating round hole at the end of the slots. It should come out like an old 8-track tape cassette with a small "spur" that keeps it seated (pull it in & out 10 times and it will no longer stay in having scraped a furrow in the cylinder), mind that spring by the way (I have not seen but one spring per wafer, just the two pieces). For extra credit, see if there are any wafers that may be traded/switched so that there are fewer that are "too low" (for too low cannot be compensated for, barring wafer replacement). See if you can match the wafers up to the key cuts so that as many as possible are "too high" in the cylinder.

Now take a small file and enlarge the "hole" in the center of the wafer where it rides on the key bumps. Doing so will lower the wafer so that its tab can get right to shear (if you are good enough with the file) OR just get it "close enough", then Dremel it. I suggest working one wafer at a time as you reassemble the cylinder.

Again, not a criticism. Just my $.o2

[WayneDW]

Does this work the other way around?  That is, can I change the ignition switch to match my gas tank key using this method?   
The reason I ask is that I have a nice folding key that fits my gas tank but only a straight steel key that fits my ignition.  So, I'd rather use the folding key as the master.
thanks.

[TaosBob101]

 The above post is a situation I find myself in....

[mystic red]

I would suggest a locksmith....if you could easily remove the lock core without a key it wouldn't be very secure.

[F14CRAZY]

I also have to ask how this works when you don't have a key to unlock the locks to get to the retainer tang

[Gio]

I have the same dilemma - recently installed low seat kit came with a lock (lever type - different than with the stock high seat), but no key (see attached) ... I tried the obvious (my existing ignition key - no joy) ... anyone know if there is a way to find out the key number - there is a 12 digit sequence on the back of the low-seat lock unit - but this may just be the generic BMW part # for the whole assy ???

Ideally I would like to get a new key for the (key-less) low-seat latch even if it doesn't match the current ignition key.

[bocutter Ed]

I would think that if you took hi and lo seat locks to a locksmith they could swap the tumblers for you.

[Gio]

Was hoping there might be an easy way to find the key # - but that's not such a bad alternative idea ... thanks.

Gio

[detbmw]

I bought two type 3 side cases, with painted lids, from two different people. One case has a key & locks, so I plan to try to re-key these three locks to my brick's key.

The other case came with no locks, so how should I proceed? Should I buy three locks from a dealer? Can someone sell me three locks with a matching key so that I can re-key them? I would appreciate any suggestions.

[Sit]

Love the internet and this site.  Purchased my 100RS with tragkorbs that were not original to the bike.  Of course the key for the bike did not work in the cases.  A quick read of this article and within minutes I had a lock cylinder out and determined that I just needed to remove one wafer and the bike key would work.  Ten minutes later the old gal is a one key bike again. :clap:

[RobP]

My key works fine in the ignition on my 'new' K100RS but the gas cap has been a real pain to unlock.  It usually takes me about about 10 minutes of fiddling to get the lock undone. 

I pulled the cap assembly off tonight for a look-see at the lock.  I ground down a couple of high wafers. You indicated not to grind down the outermost retaining tang/wafer.  Is this supposed to retract in some way when the key is turned?  It always extends out whether the key is in place or not. This seems to be what is keeping the tumbler from turning.

[bocutter Ed]

You indicated not to grind down the outermost retaining tang/wafer.  Is this supposed to retract in some way when the key is turned?  It always extends out whether the key is in place or not.

It's not supposed to retract, except when you push down to remove tumbler assembly. If you file it down I think the assembly will come out with the key.

[Stickersman]

Hello guys,
is there any chance in the world to get the lock barrel out without the key?

I've got a spare one to replace mine (broken tang) but came with no key and it's locked in position 1, that's left.

Thanks!

[Conrad325i]

If anyone is interested, I have the CAD file (stl or stp whichever your preference) for a solution to a bad cylinder for the gas cap that will allow the gas cap to be opened perfectly with any implement (key, screwdriver, etc.)
I had it 3d printed by a buddy of mine.
I am in the process of designing one that will replace just the cylinder but it will have to be more clever.

[ArvidLO]

Hi! I'm totally new here and also super-noob on k75's!
I bought mine recently and am looking for two side-boxes 3rd gen, so i can fit my helmet and clothes in them, I ride winter-time in sweden, so hate to carry around all that gear to work and in restaurants :/
is it possible to do this with a lock on a box without the original keys? I'm thinking of buying a pair without keys that are open.

[Filmcamera]

I am trying to swap the locks from one set of cases to another.


I have managed to depress the retaining tang and remove the first one. I have also installed it in the other case - the question is, how do I get the retaining tang to redeploy to keep the lock in place again in its new home?

[Filmcamera]

That doesn't work for me.  The lock rotates freely though a full circle and more when it is installed. With the lock out I can redeploy the tang by pushing it from the other side with a jeweller's screwdriver but I can't get access to do the same once it is installed in the case lock  :dunno

[Filmcamera]

Yep


I did


Redeploy the tang before installing the lock - then turn and presto - it works

[alcorelli]

 does anybody know how to get the lock cylinders out when you don't have a key. I have side cases a top case a gas cap and the helmet lock that don't match my ignition key and all I have is my ignition key. It's easy to do on the later system cases without a key but I'm not able to do it on this K bike. I love to pay a locksmith but we're looking at 7 cylinders. That's going to cost a fortune on a bike that I didn't pay a lot of money for.


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[Laitch]

. . . It's easy to do on the later system cases without a key but I'm not able to do it on this K bike.

How do these locks and latches differ from the ones you removed without a key? If locks are easy to remove without a key, what good are they anyway?

If you want to gamble that all those locks have the same key, remove the helmet lock and take it to a locksmith to get a key made for it, otherwise, you could drill out the rivets on one of the latches, remove it lock-and-all and explore the possibilities.
 

[alcorelli]

It is an 85 K100. The ignition key works in the helmet lock but not the gas cap. Figured the gas cap lock was just stuck as the keyb did not turn.
I bought some factory cases for it that did not come with a key. My assumption was that, like the later 1990s system cases, the cylinders could be removed without a key. I've changed many lids, cylinders and lock mechanisms on those newer cases, most times without keys.

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