just got an 03 polaris 500 sportsman.. has engine knock and im trying to diagnose.. not sure where comin from.. already checked valves and clutches..only 750 miles on it..

 

Mine done same thing here a while back and it ended up being the exhaust valve rocker arm so had to replace that and cam and timing chain.

 

Did you pull the front clutch off to eliminate it as a problem? I've found front clutches worn so bad on the spider where the ramp buttons glide sounded like a diesel engine from the slack,making a clacking noise. 750 miles is nothing on 500 engine if it's been properly maintained and using the correct oil. 2w50 Polaris OR 0w40 synthetic Mobil1,Amsoil,etc. As far as that goes clutch buttons shouldn't wear out in that length of time either unless it's been really abused. OPT

 

welcome to the forum. so you know it's not a bent valve? maybe cam chain hitting? very loud and metal to metal sound for sure.

 

got it.. piston slap//and alot of it..gonna order new piston and bore jug.. guessing .060 will get scarring out

 

Make sure you check the rod for any up and down movement at the crank. Doesn't usually happen,but best to make sure. OPT