2010 Polaris Sportsman 850 Service Manual, Page 142Get this manual
ENGINE Counterbalance Shaft RemovalInspection
1Note timing marks on balance shaft drive gears and crankshaft drive gearShafts must be properly timed upon assemblyMark each shaft location for assembly (starter side or oil pipe side)Lift both balance shafts from upper crankcase and remove end plugs6Hold main gear (A) and rotate split gear counterclockwise (viewed from gear end) to compress springsSplit gear should rotate and return freely and completely without binding