Ducati 999 Manuel D'utilisation page 166

If you wish to set steering head angle at 23° 30', match
the last hole at the front end of the steering lock peg (3)
with the mounting hole in the steering head. Apply
medium-strength threadlocker to the screw (2) and use
the screw to secure the steering damper, after installing
the steering lock peg (3).
Rotate the ball joint (A) of the steering damper rod
through 180°. Apply medium-strength threadlocker to the
screw (1) you have removed previously and secure the
steering damper with the screw.
E
Grease the screw (4) you have slackened previously and
tighten.
A
1
fig. 63.1
67