2008 Polaris ATV Sportsman 300 400 H.O. Service Manual, Page 88Get this manual
ENGINE (300) 456Disconnect wire or tie strap securing cam chain (if used)Be sure the pin on the camshaft is pointing DOWNLoop the cam chain over the sprocket and shift the chain on the sprocket until it can be installed onto the camshaft2With the plunger retracted, install the tensioner assembly with new gasket and tighten the bolts to specification
7VERIFY the following: "T" Mark on flywheel is aligned with the projection in the timing hole of recoil housing The mark (A) on the camshaft sprocket is aligned with the projection (B) in the camshaft cover window as shown above8Verify all marks are alignedInstall the cam sprocket bolt and torque to specification3Tensioner Bolt Torque: 5-6.5 ftlbs(7-9 Nm) Install the pin, spring, and tensioner cap with new sealing washerTorque cap to specification