2008 Polaris ATV Predator 50, Sportsman Outlaw 90 Service Manual, Page 58Get this manual
ENGINETRANSMISSION 45Measure O.Dof rocker shaft in places (E)Measure I.Dof rocker arm (F) and compare to specificationInspect rocker adjuster screws (G) and the end of the valve stems for wear, pitting, or damage to threads of the adjuster or locknutReplace all worn or damaged partsNOTE: Adjuster face is hardened and cannot be ground or refacedInspect for Areas of Tooth Wear or Damage Measure height of each cam lobe (H) using micrometerReplace cam if worn below minimum heightCompare to specificationCheck bearings for wear, roughness, or damage