1980 Ski-Doo Shop Manual, Page 100Get this manual
SECTION 03 SUB-SECTION 02, (ENGINES)
valve adjustment with replaced crankcase having no timing marks
From top edge of magneto side inlet port, mark crankcase
1980 444 type: 141 opening 51 closing
To correctly install the rotary valve proceed as follows:Turning crankshaft counter-clockwise(drive pulley side) bring magneto side piston to Top Dead Center uSing T.D.CgaugePosition the rotary valve on gear to have edges as