2005-2008 Honda ATV TRX500FA/FGA Fourtrax, Rubicon Factory Service Manual, Page 78Get this manual
MAINTENANCE To prevent damaging the iridium center electrode, use wire type feeler gauge to check the spark plug gapDo not adjust the spark plug gapIf the gap is out of specification, replace it with new one
Check the gap between the center and side electrodes with wire type feeler gaugeMake sure that the 1.0 mm (0.04 in) plug gauge
WIRE TYPE FEELER GAUGE
does not insert between the gap
If the gauge can be inserted into the gap, replace the plug with new one
INSTALLATION
To prevent damage to the cylinder head, hand-tighten the spark plug before using wrench to tighten to the specified torque