1999-2002 TRX400EX Fourtrax Service Manual, Page 41Get this manual
MAINTENANCE Check the insulator for cracks or damage, and the electrodes for wear, fouling or discolorationReplace the plug if necessary (recommended spark plug: page 3-1)CENTER ELECTRODE
SIDE ELECTRODE
Clean the spark plug electrodes with wire type brush or special plug cleanerCheck the gap between the center and side electrodes with wire-type feeler gaugeIf necessary, adjust the gap by bending the side electrode carefullySPARK PLUG GAP 0.6- 0.7 mm (0.024- 0.028 in) CAUTION:
Toprevent damage to thecyinderhead, hand-tighten thesparkpug before using wench to tighten to the specified torque