Spark Plug - Suzuki RM-Z250 Owner's Manual

SPARK PLUG

• Remove the seat. (4-2)
• Remove the radiator covers and fuel tank. (4-2)
• Hold the cylinder head cover bolt immovable with the wrench.
• Disconnect the lead wire coupler from the ignition coil/plug
cap.
Disconnecting the lead wire coupler improperly can
damage the coupler.
Disconnect the lead wire coupler before removing the
ignition coil/plug cap to avoid lead wire coupler dam-
age.
• Remove the ignition coil/plug cap.
Do not pry up the ignition coil/plug cap with a screw
driver or a bar to avoid its damage.
Be careful not to drop the ignition coil/plug cap to pre-
vent short/open circuit.
• Clean the ignition coil/plug cap and spark plug hole.
• Remove the spark plug with the spark plug wrench.
NOTE:
Remove the dirt around the spark plug before removing the
spark plug to prevent dirt from entering the combustion cham-
ber.
 09930-10121: Spark plug wrench set
• Inspect the spark plug condition, electrode color, carbon
deposits, spark plug gap and insulator damage.
• If it is extremely worn or burnt, replace the spark plug.
Also, replace the spark plug if it has a broken insulator, dam-
aged thread, etc.
• Inspect the porcelain tip color.
Porcelain tip color
White (overheated)
Black (fouled)
NOTICE
NOTICE
Cause
• Hot type spark plug
• Advanced ignition timing
• Lean air/fuel mixture
• Deteriorated fuel
• Cold type spark plug
• Retarded ignition timing
• Rich air/fuel mixture
PERIODIC MAINTENANCE 2-7