1985-1986 Honda Fourtrax 125 TRX125 Shop Manual, Page 27Get this manual
MAINTENANCE
SPARK PLUG
Disconnect the spark plug cap and remove the spark plugVisually inspect the spark plug electrodes for wear
0.6-0.7 mm (0 024-0028 ;nl-
CENTE ELECTRODE
CHECK, GAP
DEPOSIT WEAR
The center electrode should have square edges and
the side electrode should have constant thicknessDiscard the spark plug if there is apparent wear or if the insulator is cracked or chippedMeasure the gap with wire-type feelegauge and adjust by
SIDE ELECT RODE
CHECKSEAL1NG DAMAGE