2003 Ski-Doo REV Series Factory Shop Manual, Page 125Get this manual
Subsection 03
Section 04 ENGINE (LEAK TEST AND ENGINE DIMENSION MEASUREMENT)
9Read the burette scale to obtain the quantity of liquid injected in the combustion chamberNOTE: When the combustion chamber is filled to top of spark plug hole, it includes an amount of 2.25 cc corresponding to the spark plug well10Repeat the procedure for the other cylinderENGINE TYPE 593 HO 793 COMBUSTION CHAMBER VOLUME (cc) (up to top thread of spark plug hole) 28.65 1.2 38.61.7,1.6
Using micrometer, measure piston skirt at 15 mm (.590 in) perpendicularly (90) to piston pin
11Install thicker or thinner cylindercrankcase gasket (refer to Parts Catalogs) in order to obtain the specified combustion chamber volume or the nearestENGINE TYPE 593 HO 793 CHANGE IN COMBUSTION CHAMBER VOLUME (cc) FOR EVERY 0.1 mm (.004 in) OF GASKET THICKNESS 0.41 0.53