1996-2005 Suzuki DF40, DF50 Four Stroke Outboard Service Manual, Page 188Get this manual
6-45 POWER UNIT (3) Calculate the pistoncylinder clearance (Clearance equals difference between piston diameter and cylinder bore measurements)Piston to cylinder clearance Standard0.020 0.040 mm (0.0008 0.0016 in Service limit0.100 mm (0.0039 in If clearance exceeds service limit, replace piston andor cylinder or rebore cylinder
Identification of oversize pistonpiston ring Oversize pistonpiston ring are marked as shown below