1978 Ski-Doo Shop Manual, Page 103Get this manual
SECTION 04 SUB-SECTION 01 (ENGINE TOLERANCES MEASUREMENT)
Accurate measurement
To determine piston to wall clearance, the piston should be measured mm (516") above its bottom edge and the cylinder should be measured 16 mm (58") below its top edge,
The thickest possible to use feeler gauge will determine the piston to wall clearance,
RING END GAP
ENGINE TYPE RING END GAP
248,294,305, 343,346,354, 247,345,402,
0,15-0,35 mm L006-,014") 0.20-0.40 mm L008-.016") 0.25-0.45 mm L010-.018")