Electrical System; Checking The Spark Plug; Checking The Ignition Timing - Yamaha YZ 2019 Series Owner's Service Manual

EAM20137

ELECTRICAL SYSTEM

EAM30254

CHECKING THE SPARK PLUG

1. Remove:
• Seat
• Air scoop (left/right)
Refer to "GENERAL CHASSIS" on page 4-1.
• Fuel tank "1"
Refer to "FUEL TANK" on page 7-1.
ECA24400
NOTICE
Do not use too much force to pull the hose.
TIP
Remove the fuel tank, turn this 180 clockwise,
and put it in the frame "2" as shown.
1
2. Remove:
• Spark plug cap
• Spark plug
Refer to "CAMSHAFT" on page 5-11.
ECA24410
NOTICE
In order not to allow the dirt accumulated
around the spark plug to drop from the spark
plug hole into the cylinder, clean it before re-
moving the spark plug.
3. Check:
• Spark plug type
Wrong type  Replace.
Manufacturer/model
NGK/LMAR8G
4. Check:
• Electrode
Damage/wear  Replace the spark plug.
• Insulator
Abnormal color  Replace the spark plug.
Normal color is medium-to-light tan.
5. Clean:
• Spark plug
(with a spark plug cleaner or a wire brush)
6. Measure:
• Spark plug gap "a"
Out of specification  Adjust the spark plug
gap.
Spark plug gap
7. Install:
• Spark plug
1
Spark plug
TIP
Before installing the spark plug, clean the spark
plug and gasket surface.
2
8. Install:
• Spark plug cap
• Fuel tank
• Air scoop (left/right)
• Seat
• Side cover (left/right)
Refer to "GENERAL CHASSIS" on page 4-1.
EAM30255

CHECKING THE IGNITION TIMING

1. Remove:
• Timing mark accessing screw "1"
2. Attach:
• Timing light "1"
• Digital tachometer "2"
To the high tension code "3".
3-36
ELECTRICAL SYSTEM
0.7–0.8 mm (0.028–0.031 in)
13 N·m (1.3 kgf·m, 9.6 lb·ft)
1