1985 Ski-Doo snowmobile Service Manual, Page 181Get this manual
Section 02 Sub-section 09
(537 ENGINE TYPE)
NOTE: Spare parts pistons and cylinders are identified with green or red dotIt IS Important to match the piston with the cylinder of the same color
12,21, Cylindercylinder head stud
Because of cap nuts, cylinder head studs have to be screwed into the cylinder so that they do not protrude by more than 43 mm (1 700") If It is not possible to obtain this length, add washer between cylinder head and cap nutShorter threaded part of stud should be screwed into cylinder
18, Circlip
To minimize the effect of acceleration forces on Clrcllp, Install each clrcilp so the Clrcllp break IS at o'clock as illustratedUsing very fine emery cloth, remove any burrs on piston caused through clrciip installation
CAUTION: Circlips must not move freely after installation if so, replace them