The 9's are recommended for that sled. If they are not fouling I wouldn't be messing around running a hotter plug. How are you checking the plugs? After a Good rip across a field or after putting around on a trail at 30mph?Jman01 said:I have a '97 polaris 600XC and currently use NGK BR9ES plugs but they seem a tad on the oily side. Would the BR8ES be worth a shot? Also what would be the correct gap sizes for the plugs for my particular sled?