BMW Motorrad R 1200 GS Rider's Manual page 170

Fuel and lubricants
Gear oils
Transmission
9
Capacity
168
Fuel grade
Fuel tank capacity
(usable)
Brake fluid
R 1200 GS
Castrol SAF XO
approx. 0.85 qt (0.8 l)
(to bottom edge of filler neck)
Super (premium) unleaded fuel to
DIN 51 607 standard, minimum
octane number 95 (RON) (AKI 90)
5.3 gal (20 l)
including approx. 1 gal (4 l) reserve
DOT 4
We recommend BMW brake fluids
Use only new brake fluid to DOT 4
specification.
Oil in fork tubes and in rear wheel
drive:
Lifetime filling
BMW recommends Castrol