Ducati Diavel Workshop Manual page 457

Fork - Steering head: front fork
Inspection of the front fork
Place the spring on a flat surface and measure the free length (L).
Service limit:
270 mm.
Renew the spring if the length is not within the specified limit.
Inspect the outer surfaces of both fork inner tubes and the internal surfaces of both outer tubes. They must be free from
scoring, steps, or dents.
Check that the outer tubes are straight:
maximum allowed error 0.10 mm.
Whenever the inner tube is removed from the sleeve it is good practice to renew the bottom bushes (9) and (23).
Check the collar (12) for distortion in the area indicated. Renew if distorted.
Reassembly of the front fork
Lock the fork tube - calliper unit.