Yamaha WR250F(P) Owner's Service Manual

Contents

3 - 47INSPADJELECTRICAL/SPARK PLUG INSPECTIONEC370000ELECTRICALEC371001SPARK PLUG INSPECTION1. Remove: Spark plug2. Inspect: Electrode 1Wear/damage → Replace. Insulator color 2Normal condition is a medium to lighttan color.Distinctly different color → Check theengine condition.NOTE:When the engine runs for many hours at lowspeeds, the spark plug insulator will becomesooty, even if the engine and carburetor are ingood operating condition.3. Measure: Plug gap aUse a wire gauge or thickness gauge.Out of specification → Regap.4. Clean the plug with a spark plug cleanerif necessary.Spark plug gap:0.7 ~ 0.8 mm (0.028 ~ 0.031 in)5. Tighten: Spark plugNOTE: Before installing a spark plug, clean the gas-ket surface and plug surface. Finger-tighten a the spark plug beforetorquing to specification b.T R.. 13 Nm (1.3 m · kg, 9.4 ft · lb)