I have a B12 engine in the EFE. Swapped the neutral switch for an 1100 EZ/ED gear position switch, connected it to the EFE clocks and it worked. It needed rearranging the pins in the plug and it showed gears correctly (shift drum rotates the other way round on oilcooled lumps).
So your 1100K engine will also accept the gear position switch and indicator from an aircooled model.
That's all using stock Suzuki parts. I have no experience with aftermarket stuff.