Attached is a pic of a hydraulic slave cylinder from a R1150 and while climbing around my chookie recently I noticed a couple of towers cast into the rear of the gearbox adjacent to the pushrod hole where the throwout bearing resides and those towers are in a very good position to attach the cylinder.
Now the question does anybody here have any knowledge of this mod being done to save me the chance to reinvent the wheel.

Hi Rick, not a direct answer to your question, but have a look at the K1200 arrangement. It has that part fitted and I would think you can do the same on an older K if the diameter of the plunjer arrangement is the same (or close) to the bearing arrangement in the old set-up. Only other thing might be the length of the push rod. Interesting!

That's an interesting thought Rick,
 I've also wondered for what reason those towers were intended, and I think you've hit the nail on the head. 

Paul.

From what I can see the towers were present right through to the end of the K1100, so there must have been a purpose in mind that was kept in train but never used and when I saw that slave cylinder on flea bay I could see how it was meant to be but being a stingy bugger wasn't going to buy it only to find it wasn't right.
Thought I would ask in case some similar thing was in place somewhere else.
Mind a piece of billet and one can magically appear as a mill strips away all the swarf that doesn't belong.
It sure has given me something to keep the fossilized brain ticking over.

Rick, a friend of mine fitted a Suzuki hydraulic clutch cylinder to a BSA A10 (just because he could!), the two fixing holes and the actuator were on the same centre line........ just like the towers and clutch pushrod on a K. 
I'll ask for the hole centres, it might be an option.

Paul.

I have a K12's six speed with attached clutch slave sitting on the shelf in the garage, as well as a five speed from a K1100RS. Does anyone require the comparative dimensions from those set ups?

Your opinion as to weather the slave would go onto a K1100 gearbox would be appreciated. Is it worth investigating further or forget it.

The K12 clutch slave mount point spacing is approximately 62+/-mm while the cast points on the K11 gearbox where a clutch slave might go measures about 73+/-mm. The difference in pushrod length is substantial as well. I don't have access to an R1150 gearbox right at the mo', but it'd prolly be worth having a squiz at that design. I'm appreciating the simplicity of the K clutch cable set up at this stage.

could an interference plate (adaptor plate ) be made to suit ?  maybe out of 3mm steel ?

Yes, it could, but there is the matter of the other important dimensions. Will the cylinder fit either 'hole'? Is its length correct? It needs a closer look best left, for me anyway, for another time.

Finding out if the slave will go into the hole without mods is important to me because if I use one on chookie it will need to be an off the shelf item. I don't want to have something break and have to get one made or modified in woop woop and have it cost an arm and leg plus interest. TWB if you can get that dimension I will owe you a nice cold coopers come October.

I can do that on Monday. I'm heading up to Canada for a few days' rest.
What switch gear would you use, as well as hydraulics at the lever? K12 bits differ from K11 quite a lot. I am going to fit K11 wiring, switches and controls on my Big Block K100 simply because it's a mess trying to adapt the K12's entrails to the K11's torso.

I am using Honda switch gear on chookie and can get a generic M/C. I would like to get rid of the clutch cable from the gearbox so to make max room for the aux fuel tank

The K1200RS clutch slave uses three bolt mounting points in an odd pattern and is under 40mm wide while the K1100 clutch slave 'hole' is, as you know, over 42+mm and two potential mounts (straight across), measured with a ruled straight edge, not a calliper. But your R1150 slave looks like a three bolt pattern as well, from the piccie you posted above.

When I get the time to focus, on Monday arvo, I'll whiz the K1200 slave out and measure the actual width of the bore and the depth too.

I'm as curious as ever what BMW's intention was with those castings on the K1100 'boxes...

very bloody interesting.

Will follow this with great interest. good luck Rick

Two Wheels Better wrote:The K1200RS clutch slave uses three bolt mounting points in an odd pattern and is under 40mm wide while the K1100 clutch slave 'hole' is, as you know, over 42+mm and two potential mounts (straight across), measured with a ruled straight edge, not a calliper. But your R1150 slave looks like a three bolt pattern as well, from the piccie you posted above.

When I get the time to focus, on Monday arvo, I'll whiz the K1200 slave out and measure the actual width of the bore and the depth too.

I'm as curious as ever what BMW's intention was with those castings on the K1100 'boxes...

 Hi there, Rick! I know its been a while but have you found out anything worth? I just happened to stumble upon those castings on the gearbox and was curious whether there is a possibility for a conversion

The closest match I could find was a R1200GSA slave but I have not got any further than that.