Checking The Spark Plugs; Adjusting The Valve Clearance - Yamaha MT-09 2021 Service Manual

EAS30620

CHECKING THE SPARK PLUGS

The following procedure applies to all of the
spark plugs.
1. Remove:
• Rider seat
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
• Fuel tank center cover
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
• Air filter case
Refer to "GENERAL CHASSIS (2)" on
page 4-10.
2. Remove:
• Ignition coil
• Spark plug
ECA13320
NOTICE
Before removing the spark plugs, blow away
any dirt accumulated in the spark plug wells
with compressed air to prevent it from falling
into the cylinders.
3. Check:
• Spark plug type
Incorrect → Change.
Manufacturer/model
NGK/LMAR9A-9
4. Check:
• Electrode "1"
Damage/wear → Replace the spark plug.
• Insulator "2"
Abnormal color → Replace the spark plug.
Normal color is medium-to-light tan.
5. Clean:
• Spark plug
(with a spark plug cleaner or wire brush)
6. Measure:
• Spark plug gap "a"
(with a wire thickness gauge)
Out of specification → Regap.
Spark plug gap
0.8–0.9 mm (0.031–0.035 in)
PERIODIC MAINTENANCE
G088879
7. Install:
• Spark plug
• Ignition coil
Spark plug
13 N·m (1.3 kgf·m, 9.6 lb·ft)
TIP
Before installing the spark plug, clean the spark
plug and gasket surface.
8. Install:
• Air filter case
Refer to "GENERAL CHASSIS (2)" on
page 4-10.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
• Fuel tank center cover
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
• Rider seat
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
EAS30622

ADJUSTING THE VALVE CLEARANCE

The following procedure applies to all of the
valves.
TIP
Valve clearance adjustment should be made on
a cold engine, at room temperature.
1. Remove:
• Rider seat
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
• Fuel tank center cover
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
• Air filter case
Refer to "GENERAL CHASSIS (2)" on
page 4-10.
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