Ducati Diavel Workshop Manual page 723

Cylinder/piston assemblies
Overhauling the piston rings
The piston rings must not show any signs of scuffing or scoring. Replacement pistons are supplied complete with piston
rings and gudgeon pin.
Checking the piston ring-grooves clearance
The maximum permissible wear limit is 0.15 mm for the top segment (1 st ) and 0.10 mm for the others (2nd and oil
scraper ring).
The piston rings must always be installed with markings facing upwards.