2002 Bombardier Quest 650XT Service Manual, Page 105Get this manual
Section 03 ENGINE Subsection 08 (CYLINDER AND HEAD)
Inspection
Using flat screwdriver, unscrew chain tensioner plunger no16Check chain tensioner plunger for free movement in the threads of chain tensioner housing
R610motr104A
1Engine support nuts
R610motr103A
Check chain guides for wearReplace as necessaryCheck spring conditionReplace if broken or wornReplace O-rings no17 and no18, if they are brittle, cracked or hard
Remove breather hose then unscrew breather screws no19Push, with your hand, the top of engine toward the LH side of vehicleAt the same time, remove the breather no20
Inspection
Check O-ring no21 and V-ring no22 on breatherIf they are brittle, cracked or hard, replace them