Just the head, the cams are different I would guess but are the physical heads the same? I've got a buggered R1150 head but good valve gear/cam - can I put an R1100S head on with the 1150 top end gear?
The R1100GS has 3, the R1100S has 2 just like the 1150. I've got an R1100S in the garage The head I want to fit on my GS came off a crashed 1100S.
I took the head off - tried (and failed) to drill out the exhaust studs that were virtually corroded through, snapped a drill bit in one, went and got it spark eroded but the drill bit seems to have conducted the heat and melted out a hole where the head mounting bolts go through All my own fault. I'll cut out stage A and go straight to the spark erosion on the other head!