The front brake discs consist of an inner carrier, which is mounted to the wheel, and an outer rotor. Both parts must be changed together as a pair.
Remove the front wheel (sect. 7 - 1, Removal of the front wheel).
Undo the retaining screws (5) of the disc to the wheel, remove the disc (7) and, on its left side, slide out the phonic wheel (6).

Removal of the front brake system
Overhauling the front brake componentsIdentification data
All ducati motorcycles have two identification numbers, for
frame (fig. 1) And engine (fig. 2).
Note
These numbers indicate the motorcycle model and
should be quoted when ordering spare parts.
...
Refitting the front sprocket
Grease the o-ring (16) and install it on the front sprocket spacer (15).
Fit the spacer, from the o-ring side, on the secondary shaft and drive it fully
home against the inner ring of the bearing.
Check that the splines of the gearbox secondary shaft and the sprocket are in
perfect condi ...
Adjusting the steering head bearings
Excessive handlebar play or shaking forks in the steering head indicate that
the play in the steering head bearings
requires adjustment. Proceed as follows:
loosen the clamp screw (1) that holds the steering tube to the steering head.
Slacken the clamp screws (2) securing the steering head ...