1980 Ski-Doo Shop Manual, Page 99Get this manual
SECTION 03 SUB-SECTION 02, (ENGINES)
(!)ThroughRotary valve shaft assemblyIf it is necessary to disassemble components of rotary valve shaft assemblycompress spring cup in order to remove circlip
From pump sideusing no420 876 510 pusherinstall oil seals (with lithium grease on lips) as per illustrations
rotary valve shaft and inside of distance sleeveAt assembly, apply "Loctite 271" inside of distance sleeveKeep in mind that:distance ring opening must be in line with crankcase draining hole