1985 Ski-Doo snowmobile Service Manual, Page 112Get this manual
Section 02 ENGINE Sub-section 05 (462 ENGINE TYPE)
To correctly install the rotary valve disc proceed as follows:
- Turning crankshaft counter-clockwise, (drive pulley side) bring magneto side piston to Top Dead Center using T.D.C gauge- Position the rotary valve disc on gear to have edges as close as possible to the marks
INSPECTION
25,28, Rotary valve, rotary valve cover
A gap of .2748 mm (0.011"0.019") must be maintain between the rotary valve and the crankcaseTo measure this gap use feeler gauge inserted between rotary valve and upper crankcase with the rotary valve cover in place without its O-ringCheck the most surface possibleFollow the same procedure with the lower crankcase