The part you've shown is the correct part for the clutch switch. It is the same part used on early K-bikes for the rear brake switch and as the choke indicator switch. It uses an M8 x .75 thread to mount and a standard 10mm hex wrench can easily be used to unscrew it from the clutch perch. I usually find enough of the hex part to engage the open part of the wrench. Once I've given it about 180* of turn, the rest is just unthreading it by hand. No problems.
Seeing that your bikes are mid-90 models, neither will have the older brake or choke switches installed. BMW stopped using this switch as a rear brake switch fairly early, replacing it with a microswitch just behind the footpeg plate.
Following up here...
First, on my 1994 and 1995 K75 that's not a 10mm nut, it's 11 mm. Second, on my bikes there's no way to get a standard hex wrench in there, whether the clutch perch is installed on the bike or not. I have the unattached perch from my parts bike on my workbench, and no 11mm open-ended wrench -- not even an 11mm flare -- will go in there with enough clearance to get any purchase on the nut. It's even worse with the perch installed on the bars, because with my RT bars the curvature of the bar blocks access to the recess where the switch connector lives.
I tried turning the rubber jacket with needlenose in the hope that the bond between the jacket and the connector would be strong enough to crack the nut so it would spin. Tip: don't do that. It's not: jacket will just rotate and the nut will stay seated.
I tried making a tool out of an 11mm wrench, see the image marked 'FAIL'. Nice try, but the recess still didn't have enough clearance to accommodate the bend in the wrench.
This worked:
1. Get a Craftsman 11mm 1/4 drive true deep socket from Sears for under $5. My local small-town family Sears franchise store had it, didn't have to drive all the way to a Sears retail store. You need a deep socket because the piece has to slip down over the rubber jacket covering the connector, and a standard socket isn't long enough. You need the 1/4 drive because wall of the the 3/8 drive socket is too thick to get down in that recess where the nut is.
2. Get your grinder with cutting wheel and cut off the drive end, leaving maybe 1 1/2 inches of the hollow socket to work with.
3. Cut a channel for the switch cable to slip through.
4. Cut a slot in the top. I cut it off center to get a flat screwdriver through, but it turns out you just need the slots. Or, if you have a drill press drill a couple holes through the whole piece.
5. Lubricate the jacket so the tool slides down over it onto the nut and tighten or loosen as needed.
You can turn the tool by putting a screwdriver blade into the slot (or a small phillips into hole, if you've drilled them) and applying torque. It doesn't take much to crack the nut off its seat, then it just turns by hand until it comes out. For tightening, it's not supposed to get a lot of torque, maybe a quarter or half turn once the nut makes contact with the seat.
If anyone else has pulled/installed this switch by other more simple means, more power to you. But if you want to remove that switch without removing the perch, disconnecting the clutch cable or dinking with needlenose pliers or wrenches that don't fit, spending the $5, making 5 minutes of cuts with your cutting wheel and making the right tool for the job as described here is a pretty good option.
