Suzuki RM125 - Spark Plug

2-6 PERIODIC MAINTENANCE
SPARK PLUG
• Inspect the spark plug condition, electrode color, carbon
deposits, spark plug gap, and washer damage, after removing
the spark plug.
NOTE:
Remove the dirt around the spark plug before removing the
spark plug to prevent dirt from entering the combustion cham-
ber.
• Inspect the porcelain tip color.
• Clean the spark plug and check the spark plug gap with a
thickness gauge.
 09900-20803: Thickness gauge
 Spark plug gap: 0.55 – 0.65 mm (0.022 – 0.026 in)
 Standard Spark plug
• Tighten the spark plug with specified tightening torque after
tightening the spark plug temporarily with fingers.
 Spark plug: 17.5 N·m (1.75 kgf-m, 12.5 lb-ft)
Porcelain tip color Cause
White (overheated)
• Hot type spark plug
• Advanced ignition timing
• Lean air/fuel mixture
• Deteriorated fuel
Black (fouled)
• Cold type spark plug
• Retarded ignition timing
• Rich air/fuel mixture
• Rich oil/gasoline mixture
NGK R6918B-8
CAUTION
Changing the spark plug heat range improperly can
damage the engine.
Select the spark plug heat range only after adjusting
the ignition timing, carburetor setting and oil/gasoline
mixture.
0.55 – 0.65 mm
(0.022 – 0.026 in)