Ducati Diavel Workshop Manual page 679

Cylinder head assemblies: timing system
Check the timing belt tension and adjust if necessary as described in the paragraph Measuring the timing belt tension
values (Sect. 6 - 11) of the vertical cylinder head belt.
Warning
Check the tension on the belt sections (D) and (E) shown in the figure.
Once the required tension has been reached make sure that the nut (8) retaining the tensioner (9) is tightened to a
torque of 25 Nm (Min. 22 Nm - Max. 28 Nm) and the screws (22) of the vertical head are tightened to a torque of 10 Nm
(Min. 9 Nm - Max. 11 Nm) (Sect. 3 - 3, Engine torque settings).
Remove the timing shaft locking tool code 88765.1623 of the vertical cylinder head.
Carry out timing on the horizontal cylinder head.
Approach the tool code 88765.1623 to insert the pins (F) in the timing shaft seats (G).