1987-2009 Yamaha ATV YFM350X Warrior Raptor Service Manual, Page 47Get this manual
NO IIA SJP -SPARK PLUG INSPECTION Standard spark plug: D8EA (N.G.K X24ES-U (N.D
3Inspect: Electrode CD WearDamageReplace Insulator Abnormal colorReplace Normal color is medium-to-light tan color4Clean the spark plug with spark plug cleaner or wire brush5Measure: Plug gap Use Wire Gauge or Feeler GaugeOut of specificationReplaceSpark plug gap: