2008 Polaris Sportsman 500 EFI/X2/Touring/500 H.O. Service Manual, Page 92Get this manual
ENGINE 7Remove large sealing O-Ring from outer edge of stator platesection of chainReplace if worn past service limitChain Service Limit: 5.407" (13.7 cm) 4Using the special socket, remove the crankshaft slotted nutNOTE: The crankshaft slotted nut is left-hand thread5678Remove cam chain drive sprocket and woodruff key from crankshaftInspect sprocket teeth for wear or damageInspect woodruff key for wearReplace any worn or damaged parts
One Way Valve Removal
The one way valve prevents oil from draining out of the oil tank and into the crankcase when the engine is offIt must be clean and have adequate spring pressure in order to seal properly
Cam ChainTensioner Blade