Ducati Diavel Workshop Manual page 778

Flywheel - alternator
Reassembling the flywheel - generator assembly
Install the starter clutch (22) in the flange (14) to bring the edge (A) of the clutch up against the flange.
Important
Assemble the components (starter clutch and flange) so that the edge (A) of the starter clutch is positioned on side of the
flange with the bevelled edge (B).
Seat the flange (14) with the starter clutch (22) in the flywheel (17), aligning the flange locating hole (C) with the
flywheel locating hole (D).
Note
The flange locating hole (C) is the hole with the countersunk lead-in (E).