2004 Skidoo ZX Series Service Manual, Page 271Get this manual
Section 05 ENGINES (4-TEC) Subsection 06 (CYLINDER AND CYLINDER HEAD)
R1004motr101A R1004motr102A
Inspection
Valve Stem Seal NOTE: Inspection of valve stem seals is not needed because new seals should always be installed whenever cylinder head is removedValve Inspect valve surface, check for abnormal stem wear and bendingIf so, replace by new oneValve Stem and Valve Guide Clearance Measure valve stem and valve guide in three places, using micrometer and small bore gaugeNOTE: Clean valve guide to remove carbon deposits before measuringChange valve if valve stem is out of specification or has other damages such as wear or traces of friction