Looking at the Repair DVD, it appears that the Wethead pedal is different from the Hexhead/Camhead(/R1150?) pedal.
The older R1200 has specific adjustment procedures for the pedal stop and piston rod "blow-by" clearances. I think I seem to recall that maybe I've read that a badly mis-adjusted piston rod on those models can cause the rear brake to lockup when applied. Possibly. (Is that vague enough?
) The point is, getting it wrong can be dangerous.
The RepROM illustration shows a similar clevis on the RTW pedal, with what might be a lock nut for adjustments, but I found NO procedure or specs for any adjustment.
If you try adjusting the rod, be sure to test the rear brake repeatedly before taking it off the center stand.
Ilium Works offers an adjustable brake pedal
, but I think it's a bit pricey for the small adjustment you want.