Spark Plug - Suzuki RM-z450 Owner's Service Manual

SPARK PLUG

• Remove the seat. (!5-2)
• Remove the radiator covers and fuel tank. (!5-2, -3)
• Disconnect the spark plug cap.
• Remove the spark plug.
" 09930-10121: Spark plug wrench set
NOTE:
Remove the dirt around the spark plug before removing the
spark plug to prevent dirt from entering the combustion cham-
ber.
• 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)
• Check the spark plug gap A with a thickness gauge.
" 09900-20803: Thickness gauge
# Spark plug gap A: 0.9 – 1.0 mm (0.035 – 0.039 in)
# Standard Spark plug
NGK
Changing the spark plug heat range improperly can
damage the engine.
• Tighten the spark plug with specified tightening torque after
tightening the spark plug temporarily with fingers.
" 09930-10121: Spark plug wrench set
$ Spark plug: 11 N·m (1.1 kgf-m, 8.0 lb-ft)
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
DIMR8A10
CAUTION
PERIODIC MAINTENANCE 2-7