1986-1989 Honda TRX250 FourTrax 250R Service Manual, Page 24Get this manual
MA INTENANCE
SP,ARK PLUG
Disconnect the spark plug cap and remove the spark plug using the wrench provided in the tool kit VisL ally inspect the spark plug electrodes for wearThe center electrode should have square edges and the side elec trode 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 feeler gauge and adjust by carefully bending the side electrode SPARK PLUG GAP: 0.7-0.8 mm (0.028-0.031 in) RECOMMENDED SPARK PLUG: NGK CHAMPION RN3C RN2C
0.7-0.8 mm (0.028-0.031 inl
(2) CENTER ELECTRODE
(3) SEALING
(4) INSULATOR
, After '88: (STD)
BR8ES BRSES