Polaris RZR XP 570 900 1000 Automatic Cam Tensioner - Black Fits All years and models of Polaris 570cc, 900cc and 1000cc engines (All RZR and Ranger models with these engines) IMPORTANT--This tensioner is for stock engines. IMPORTANT! This is not for 'built' engines w/ aftermarket valve springs. Eliminates cam timing jump which is caused by the OEM tensioner. Maintains tension while the vehicle is on its side or upside down unlike the OEM tensioner. Eliminates engine noise / start up rattle caused by your stock tensioner.