Ducati Diavel Workshop Manual page 498

Swingarm
Refit the shims (12) and (9) from the right-hand side of the swingarm (8) and refit the bush (4) from the left-hand side.
Note
The spacer (9) with the larger external collar goes on the external side of the swingarm, whereas the spacer (12) with the
smaller external collar goes on the inside.