1979 Ski-Doo Supplementary Shop Manual, Page 50Get 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
RING END GAP
ENGINE TYPE RING END GAP
248, 294, 343 354 247, 402, 440 444, 454, 503 640
0.150.35 mm L006014") 0.200.40 mm L008"016") 0.250.45 mm LOlO.018")
Position ring half way between transfer ports and intake port On rotary valve engines, position ring just below transfer ports16mm
NOTE: In order to correctly position the ring in the cylinder, use piston as pusher
Using feeler gauge, check ring end gapIf gap exceeds specified tolerance the ring should be replaced