2008 Polaris ATV Predator 50, Sportsman Outlaw 90 Service Manual, Page 56Get this manual
ENGINETRANSMISSION USE THE FLYWHEEL TIMING MARK 123Remove timing hole plug from flywheel coverRotate the engine in normal direction of rotation and watch the intake valve open and then closeView straight into the timing hole and continue rotation engine until the "T" mark on flywheel (E) aligns with the groove in the timing hole (F)There should be clearance on both valves
Cam Chain Tensioner Removal
NOTE: Tensioner can be removed with engine in frame12Find TDC on compression strokeSee "Finding Top Dead Center (TDC)" on page 3.13 Remove camshaft tensioner cap with spring (C)