Ducati Diavel ABS 2012 Owner's Manual page 187

Refit the left cowling (1, fig. 157) as follows:
start the side screw (2, fig. 157) retaining the
electrical parts box in its thread;
start the top screw (3, fig. 157) retaining the electrical
parts box in its thread;
start the bottom screw (4, fig. 157) retaining the
3
central cowling in its thread;
1 2
4
fig. 157
185