ATV Repair and Maintenance Firing problem October 15, 2015 I have a 1999 Polaris sportsman 500 and it idles fine but when i hit the gas it backfires through the carburetor, i just put a new carb kit on it, it still does it has anyone else had this problem and what could it be. Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related