Ducati MULTISTRADA 1200S ABS 2015 Workshop Manual page 791

Refitting the tank filler plug
Duly grease the new sealing washer (4) and its seat on tank.
Position the complete filler cap (2) paying attention to fit the two breather hoses (3) in the relevant seats.
Start and tighten the six securing screws (1) to a torque of 4 Nm ± 10%.