Remove the seat and turn it upside down.
Loosen the special screws (4), turn the plates (5) and open the seat cover (2) lateral sides to slide it out.

Removal of the seat
Reassembly of the seatEngaged gear indicator
This function displays the gears (1, fig. 25).
The instrument panel receives information and indicates the
engaged gear or "n" for neutral.
Note
In the case of a gear sensor "error", a dash "-" (not
flashing) will be displayed.
...
Specific tools for the frame
88713.1072 Drift to install half bearing in bottom yoke
88713.2562 Chain assembly tool
88713.1058 Wrench for steering shaft nut
88713.1062 Tool for installing steering head bearings
88713.2951 Rear wheel balancing tool
88713.3211 Wrench for adjustment of the eccentric hu ...
Replacing the rear phonic wheel sensor
Disconnect the rear abs sensor (5) connector (c) from the main electric
wiring.
Open all the retainer clamps of the rear abs sensor cable (5): refer to table of
sect. 7 - 6, Flexible wiring/hoses
positioning.
Remove the rear abs sensor (5) from its seat on the rear calliper mounting ...