"If I were as baffled as you and this were my bike, I'd remove the cable then measure it. Eventually though, somebody should drop that transmission and inspect the clutch pack, splines and the rest of the linkage."
If this were your bike, it wouldn't have got this far. Somewheres along the way, when the side stand stopped trippin & the clutch thumbwheel nuts wouldn't cinch up any more & you bnegan to hear the throwout bearing, you would've looked into it. This guy is not the least mechanically inclined. He's more of a farmer and a writer. Detests wrenches.
Now, this is gonna upset you guys, & I understand that, cause you are brick enthusiasts of the highest order. But here's the deal: What are bricks worth? Not talking about their intrinsic worth; talking about what you could buy one for. I see fine looking K75Ses for sale for 1200, 2200, 2400. Sure, there's a handful of delusional beemeristas asking the price of a brand new CTX700. Pay no attention; that's just beemeristas. Truth is, ride this one into the ground & then score another. Never pay more for repairs than the machine is worth. Subtract from your considerations any pleasure you would get hanging in the garage bringing a brick back to life over Winter. That's not him. He's the guy would take it to Bob's BMW.
& Bob's would prolly tell him the same thing. I'd hope.