Ducati Diavel Workshop Manual page 106

Fairings
Lubricate the seals (D) of the central tank cover (22) using lubricant specific for rubber.
Position the front RH half-fairing (1) by inserting the tabs (C) into the seals (D) pushing downwards (blue arrows); after
that, slide the half-fairing completely to the rear side of the motorcycle (red arrows).
Block the front RH half-fairing (1) by forcing pin (A) into the receptacle (B) in the RH water radiator.
Warning
Before pushing on the pin (A), make sure it is centred in the receptacle hole (B). Then – and not until after checking for
proper position – push moderately and increasingly harder until you hear the component engage.
Before tightening the screws securing the front left half-fairing (12) and the front right half-fairing (1), proceed as follows:
Visually check the distance between the front left half-fairing (12) and the central tank cover (22) along the upper mating
edges of both parts.
Visually check the distance between the front right half-fairing (1) and the central tank cover (22) along the upper mating
edges of both parts.
If the parts do not mate equally, shift the front half-fairings (12) and (1) forward or backward as required until achieving
a condition in which the half-fairings (12) and (1) are at the same distance from the central tank cover (22).
After tightening, check again to ensure that the front half-fairings (12) and (1) are at the same distance from the tank
cover (22). If not so, repeat the above procedure.