(Applies to 2V Ks only.)

At least in the US, K bikes no longer had a choke indicator light in the cluster after 1990.  However, it's quite easy to get that functionality back on 91+ bikes.  All you need is a piston switch (same as the switch used for the front brake and clutch) and a spacer ring. Even though BMW didn't install the switch, the wiring that connects it to the cluster is still there.

The switch installs in a threaded hole in the rear of the throttle bodies.  It's easiest to do this if you get the throttle position sensor and crank case breather hose out of  the way. Then use an 11mm open end box wrench to install the switch with the spacer ring below it.

Here's a picture I took from a 91 K75S I just did this to:




Once you have the switch installed look for an unused two wire connector (violet/white & brown) under the front left of the gas tank.

Would you also have to install a new bulb in the appropriate lamp socket inside the instrument cluster? Or is that bulb supplied by BMW anyways?

I have done this on my k1 - success :-)  but on my k1100rs (93) I added the switch to discover  the wire is missing from the loom that feeds the bulb (i.e. no pin in the plug), when time permits I will retrofit a wire. I don't recall having to fit a bulb but it only takes a few minutes to add one.

I have retrofitted that switch to four bricks now, and yes, the bulb is in the cluster of K75's and K100's so you just need to add the switch.  I haven't used the spacer, just adjust how far I screw it in.  Be prepared to spend some time getting it screwed in.  I have found that a hair dryer to soften up the switch's cable can make the job a bit easier if you do it in a cold garage.

Thanks for the tip on adding a choke light to 90+ bricks. Hate to admit this but I spent time trying to troubleshoot this before I realized that it was not installed from the factory. The good news is I did take the time to bend my float arm for the low fuel light so it didn't come on with over a 100 miles of range left in the tank (got it set to come on with one gallon left, 40-50 miles depending), love having 250 mile range on the 75s!

Just added one to my K100 16v and the bulb now works, it was already in the console.

This are a bugger to fit on the bike. It is in a really awkward position to screw in.

So if you have the throttle bodies off the bike fit it then.