Where is the spark plug on 2003 polaris sportsman 500 ho?

On a 2003 Polaris Sportsman 500 HO, the spark plug is located on the engine's cylinder head, typically on the right side when facing the front of the ATV. You will need to remove the plastic cover to access it. The spark plug is connected to a wire, which you can detach to replace or inspect it. Make sure the engine is cool before attempting any maintenance.