I found this nifty hour meter (stundenzähler!) at a KTM shop. It mounts nicely to the right side of the lower air box with double-sided foam tape (included). A sensor wire simply wraps around the front-cylinder spark plug wire which is handily right there! It counts hours of running-time and is non-resettable.
Update: Heat, oil and vibration caused the double-sided tape to fall off. Mount with screws instead!