Logbooks of '72 R75/5, '79 R100T, '82 R80G/S Paris-Dakar, '93 R100GS PD, '71 CB750 and others, a.k.a.
Neimann keys decoded
So, I had this key and needed a new seatlock: no key code, just the key. Searched the internet and it came up with the information: There are 5 cuts in equal distance from the key stop, the deepest is a 1, no cut is a 5. See a couple of examples hereafter.
Addendum thanks to Kenny from Huntsville, AL
(email Kenny directly)
... I took my cylinders out and measured the actual spacing between "tumblers" at 2.68 mm and the distance to the first cut is 3 mm.
The "tumblers" are only 0.67mm thick and the slots that they ride in are 0.90 mm so there is quite a bit of flexibility and slop if you use a round file. Now i was able to fine tune the key by fitting it to the cylinder and making adjustments--it's perfect.
I used SR61N blanks but had to file off the hump of the big key stop to make them work.
Also you may be interested to know that if you measure the distance from the rail slot on the reverse side (seen in your pictures key 4 and 5) to the bottom of the "cut", the distance is an even value: Codes 1,3, and 5 are 1.0, 2.0 and 3.0 mm, and Codes 2 and 4 are 1.5 and 2.5 mm from the rail edge to the correct "cut depth" for that particular Code number. ... The measurement is easy using an outside-measuring caliper.