1989 Ski-Doo Repair Manual, Page 170Get this manual
Section 02 ENGINE Sub-section 06 (536 ENGINE TYPE)
2, Rotary valve cover bolt
The rotary valve cover bolts must be torqued to 20 Nm (15 Ibf.ft)
7,15, Rotary valve shaftgear
Backlash check Engine do not have to be overhauled to check backlash of crankshaft and rotary valve shaft gearsRemove spark plugs, cover and rotary valveCheck backlash at one position then turn crankshaft about 118 turn and recheckContinue this way to complete one revolution Backlash must be even at all positionsOtherwise overhaul engine to find which part is faulty (gear, rotary valve shaft or crankshaft with excessive deflection)Check for presence of brass filings in gear housingReplace gear if needed Besides, check deflection of rotary valve shaft and crankshaft close to gearReplace as neededMAXIMUM ROTARY VALVE SHAFT DEFLECTION