Warning
The brake master cylinder manufacturer advises against servicing the brake master cylinder due to the safety critical nature of this component.
Incorrect overhaul can endanger the rider and passenger.
Maintenance operations on these units are limited to renewal of the following parts: control lever, fluid reservoir assembly and relative fasteners and master cylinder fasteners.

Note
For the abs front braking system, also refer to sect. 7 - 5, Abs system operating information, sect. 7 - 6, System components, sect. 7 - 7, Abs components maintenance.
Slide the adjusting rod (18) out of the rear brake master cylinder (16).

Loosen the special screw (22) from the master cylinder (16); slide out the hose (7) and recover the sealing washers (23).
Loosen the rear brake master cylinder (16) retaining screws (19) and remove it from the vehicle.

Undo the fixing pin (9) of the brake lever (6), collecting the spring (4).

Remove the brake lever (6) and collect the pin (9), the washer (3), the bush (10) and the o-ring (11).

Rear brake
Disassembly of the rear brake controlRemoval of the fuel tank filler cap
Remove tank covers (sect. 5 - 2, Removal of the fuel tank fairings).
Remove hoses (8) and (15) from the filler cap assembly (10).
Open the filler cap.
Unscrew the outer screws (17) securing the ring nut to the filler cap recess.
Remove the filler cap assembly (10).
...
Overhaul of the cylinder barrel/piston components
Overhauling the cylinder
Check that the walls of the cylinder bore are perfectly smooth. Measure the
cylinder bore diameter at 50 mm from the top
face and determine the size class to which it belongs in accordance with the
values specified in sect. 3 -
1.1Cylinder/piston. Repeat measurement o ...
Tank filler plug
Note
To open or close the tank filler plug using the active
key, set the metal part in the middle position, as shown on
page 86.
Opening
Lift the cover (1, fig. 100) And insert the active or passive key
into the lock. Give the key a 1/4 turn clockwise to unlock.
Lift the plug (2, fig. 101) ...