2022 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.

4V Ignition Switch & Fork Lock

K1, K100RS4V, K1100

Operation:

 

The 4V ignition switch has four positions:

Position Electric Key Removable Forks Locked
1 Parking & tail lights on Yes Yes
2 All off Yes Yes
3 Radio & map light (K1100LT) Yes No
4 All on - riding position No No

 

Fork Lock: To turn the key to position 1 or 2 in order to lock the forks the steering needs to be turned to full lock right and then backed off to the left by a tiny amount.

Since many riders only use positions 3 and 4 it is not uncommon for the fork lock to be a little stubborn. Try wiggling the forks at full lock right while attempting to turn the key CCW. (Counter Clockwise) Be careful not to use he-man force and break the key off in the lock. It may take a little fiddling to get a sticky fork lock to engage so be patient.

In order to keep from draining the battery, it's not a good idea to leave the key in position 1 for an extended period of time.

Ignition Switch Overview:

For anti-theft reasons, the ignition switch/fork lock assembly is built into the upper triple tree. In addition to making theft difficult, this also complicates maintenance.

The assembly is bolted into the upper triple tree using M8x31 security bolts. It's probably possible to drill a hole in the center of each bolt head and use an easy-out to unscrew these but I usually drill a small pilot hole in the center of each bolt's head and then drill the heads off with a 5/16" or M8 drill bit. The assembly then comes out from the bottom of the triple tree.

When reinstalling the assembly I use regular M8x30 socket cap bolts.

 

Here's what the assembly looks like once removed from the upper triple tree.

While you have it out of the fork tree, it's a good idea the spray some silicone lubricant into the fork lock bolt and work it in. To remove the lock core stick the butt of a 2mm brill bit into the hole to depress the tab and wiggle the lock core out.

 

Wiring Harness Connector:

It's not uncommon for the wiring at the base that goes to the main wiring harness to go bad. That is a separate part - BMW # 61322305292. It is held in place by a grub screw under red paint.

 

Ignition Switch Wiring:

Pin Wire Color Description
2 Red 12V+ in from battery
3 Green 12V+ out to many things
6 Gray/Blue Instrument cluster & gauges backlights
7 Gray Parking & tail lights
8 Violet Radio & map light (K1100LT only)

 

Ignition Switch Testing:

Continuity at connector for various switch positions:

Switch Position

Connections

1

2-7

Red-Gray

2

None

3

2-8

Red-Violet (K1100LT)

4

2-3

2-8

3-8

6-7

Red-Green

Red-Violet

Green-Violet

Gray/Blue-Gray

 

Lock Core Removal:

For lock core removal information click here.

 

2022 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.