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 componentsRefitting the starter motor gear
Position the washer (20) and the gear (19) in the pin (21) and take the pin
into contact with the crankcase half.
...
Reassembly of the crankcase halves
If removed, apply threadlocker on the screw (36), insert it with the washer
(37) on the crankcase half and tighten it to The torque of 8 nm
(min. 7 Nm - max. 9 Nm) (sect. 3 - 3, Engine torque settings).
If removed, apply threadlocker on the dowel thread (35), tighten it to a
torque of 20 ...
Hands free key (hf) not recognised
The activation of this (amber yellow) "warning" indicates that the hands free
system does not detect the active key (1,
fig.62) Near the vehicle.
Note
Check that the active key (a) is near the vehicle (and has not been lost)
or that it works properly.
...