Thanks in advance. Not sure if has been asked before but could not find it. Has anyone replaced the OEM spark plugs for a 2012 Kawasaki er6n NGK CR9EIA-9 with the standard plug NGK CR9E? They are the same dimensions thread size etc and the only thing different as far as can see is the spark end is a mm or so shorter on the CR9E. Bike has only done 2500Klm and started surging and misfire on weekend.Have stripped down to remove plugs but no iridium plugs in area and will have to wait but can get hold of the cheaper ones. CR9EIA =$26 each and CR9E=$6.50 each.