The 4 spark plugs are under the Air box. First take off the gas tank and then the air box and you will find the spark plug wires. Take those off and remove the sparkplugs to change.
Remove the seat , look through the opening where the gas tank meets the rear plastic fairing . You should see the spark plug boot.
bad plug bad plug cap stator
0.7-0.8 mm (0.028 - 0.031) (in)
PThe best plug is prob the standand or a pltuimum plug ngk