If the spark plug center electrode [A] and/or side electrode [B] are corroded or damaged, or if the insulator [C] is cracked, replace the plug.
If the spark plug is dirtied or the carbon is accumulated, replace the spark plug.
If the gap is incorrect, replace the spark plug.
Spark Plug Gap: 0.8 
0.9 mm (0.031
0.035 in.)
Standard Spark Plug Type: NGK CR9EIA-9
Stick Coil Primary Peak Voltage Inspection
Interlock Operation InspectionSprocket Wear Inspection
Visually inspect the engine and rear sprocket teeth for
wear and damage.
If the teeth are worn as illustrated, replace the sprocket,
and inspect the drive chain wear (see Drive Chain Wear
Inspection in the Periodic Maintenance chapter).
Worn Tooth (Engine Sprocket) [A]
Worn Tooth (Rear ...
Upper Crankcase Assembly
When installing the breather plate, replace the gasket [A]
with a new one.
Apply a non-permanent locking agent to the threads of
the bolts [A] and tighten them.
Torque - Breather Plate Bolts: 9.8 N·m (1.0 kgf·m, 87 in·lb)
Install the fitting [A] until it is bottomed ...
Clutch Plate, Wear, Damage Inspection
Visually inspect the friction and steel plates for signs of
seizure, overheating (discoloration), or uneven wear.
Measure the thickness of each friction plate [A] at several
points.
If any plates show signs of damage, or if they have worn
past the service limit, replace them with new on ...