Ducati Diavel Carbon Owner's Manual page 146

The knob (3, fig. 116) located on the expansion
reservoir of the shock absorber adjusts the damping
during the compression phase.
Turning the adjusters (1) or the knobs (2) and (3)
clockwise to increase preload damping; they
decrease turning them in the opposite direction.
STANDARD setting; from fully closed (clockwise)
loosen:
adjuster (1, fig. 114) by 12 clicks;
knob (2, fig. 115) FULLY OPEN (counter clockwise);
adjuster (3, fig. 116) by 25 clicks.
Warning
The shock absorber is filled with gas under
pressure and may cause severe damage if taken
apart by unskilled persons.
When carrying a passenger and luggage, set the rear
shock absorber spring to proper preload to improve
motorcycle handling and keep safe clearance from
the ground. You may find that rebound damping
needs adjusting as well.
3
fig. 116
145