Ducati Monster S4R Owner's Manual page 132

Note
The procedure described here is in compliance with
the "Italian Standard" establishing the maximum height
of the light beam.
Owners in other countries will adapt said procedure to
the provisions in force in their countries.
The height of the light beam can be corrected using the
screws (1, fig. 62) that secure the headlamp to the side
supports.
E
1
fig. 62
57