Ducati Diavel Workshop Manual page 65

Maintenance operations
If detected values exceed the specified limits, replace opening and/or closing shims, as described in paragraph "Removing
the valves" (Sect. 9 - 4.5), with an adequate height to obtain the specified clearance.
Note
Opening rocker arm shims measuring from 1.8 to 3.45 mm and closing rocker arm shims measuring from 2.2 to 4.5 are
available as spare parts. The size is punched on the shim.
Remove the handgrip tool 88713.0123 from the hole of the generator cover.
Make sure that the O-ring (3) is fitted on the cover (2).
Refit the external cap (2) by tightening the two retaining screws (1) to a torque of 10 Nm (Min. 9 Nm - Max. 11 Nm)
(Sect. 3 - 3, Engine torque settings).
Operations Section reference