Ducati Diavel Workshop Manual page 747

Clutch assembly: primary drive gears
Refit the oil pump (D) and check the clearance between the oil pump gear and primary drive gear on the crankshaft
(Sect. 9 - 2.1, Refitting the oil
Thoroughly degrease the mating surfaces of the clutch bell (1).
Fit the spacer (2) onto the primary shaft. Fit the clutch housing (1) along with the driven gear (A).
Operations
Refit the complete clutch assembly 9 - 6.1,
Refit the clutch cover
Refill the engine with oil
1
pump).
Section reference
Reassembling the clutch
9 - 6.2, Refitting the clutch-side
crankcase cover
4 - 3, Changing the engine oil and
filter cartridge