There is a drilling in the side of the plug in which you can put a size 3 Allen key or a Torx key T10 (usually found in the your BMW toolkit) in order to fit and remove it.
See tools
BMW RnineT, RnineT Scrambler, Pure, Racer, Urban G/S & RnineT /5
Also referred to as oil filler cap.
This brake pedal enlargement is nicely machined aluminium,...
This cover for the axle pivot for all new R1200, K1200 and...
These retro infill panels for your BMW RnineT, RnineT...