Ducati MONSTERS4R Manuel De L'utilisateur page 123

Checking brake and clutch fluid level (fig. 48)
Fluid level should never fall below the MIN mark on each
reservoir.
If level drops below the limit, air might get into the circuit
and affect the operation of the system involved.
Brake and clutch fluid must be topped up and changed at
the intervals specified in the routine maintenance chart -
refer to the Warranty Card - by a Ducati dealer or
authorized workshop.
E
Important
It is recommended all brake and clutch lines be
changed every four years.
Brake system
If you find exceeding play on brake lever or pedal and
brake pads are still in good condition, contact your Ducati
dealer or an authorized workshop to have the system
inspected and any air drained out of the circuit.
Warning
Brake and clutch fluid and will damage paintwork
and plastic parts if accidentally spilled.
Hydraulic oil is corrosive; it may cause damages and lead
to severe injuries.
Never mix different quality oils.
Check seals for proper sealing.
48
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Clutch system
If the control lever has exceeding play and the
transmission snatches or jams as you try to engage a
gear, it means that there is air in the circuit. Contact your
Ducati dealer or an authorized workshop to have the
system inspected and air drained out.
material wears down.
Do not exceed specified level (3 mm above minimum
level).
Warning
Clutch fluid level will increase as clutch plate friction
fig. 48