2008 Suzuki LT-A400/F, LT-F400/F ATV Service Manual, Page 37Get this manual
Maintenance and Lubrication:
Spark Plug Inspection and Cleaning
Inspect spark plug Every 000 km (1 200 miles, months)
B827H20206005
Heat Range 1) Remove the spark plugRefer to "Spark Plug Removal and Installation in Section 1H (Page 1H3)"2) Check spark plug heat range by observing electrode colorIf it appears white or glazed, replace the spark plug with colder type oneHeat range Hot type NGK CR6E DENSO U20ESR-N Standard CR7E U22ESR-N Cold type CR8E U24ESR-N