1972 Ski-Doo Shop Manual, Page 181Get this manual
CLEANINGINSPECTION
5Check ring end gapPlace ring in cylinder half way between transfer port and intake portUsing feeler gauge, measure clearance between ring ends (fig2-8-7)The ring end gap tolerance is .008 to .063 inch
cylinder top (see fig2-83)Subtract the two (2) measurements to find clearanceIt must be within dimensions shown in Table 2NOTE: The maximum wear limit is JYJ7 inchEngine Type 247 302,337,343 and 401 292,434,.435,640 and 641 775 Cleaning when reboring .003 to .004 inch .0035 to .004 inch .004 to .005 inch .0047 to .0055 inch 6Measure crankshaft deflection as follows: