2003 Ski-Doo ZX Series Factory Shop Manual, Page 132Get this manual
Section 04 ENGINE Subsection 03 (493, 593, 593 HO, 693, 793 AND 793 HO ENGINE TYPES)
At assembly, place the pistons over the connecting rods with the letters "AUS" (over an arrow on the piston dome) facing towards the exhaust port
All Models CAUTION: Always install new circlipsTo minimize the effect of acceleration forces on circlip, install each circlip so the circlip break is at o'clock as illustratedUse appropriate piston circlip installerENGINE TYPE 493 PISTON CIRCLIP INSTALLER (PN) 529 035 561 529 035 686