I have a '03 Polaris Sportsman 400 with about 10 hours and 75 miles. The engine from the start has knocked. Not real loud but noticeable. My last ATV was a 250 two-stroke so I'm not that familar with the "normal" sounds a four-stroke makes. Should I be concered?

 

Take to dealer and start up some new 400's and see if they knock!!!

But I'd say no knock is good.