EAU00462PERIODIC MAINTENANCE AND MINOR REPAIR
To install a spark plug
1. Measure the spark plug gap with a
wire thickness gauge and, if neces-
sary, adjust the gap to specification.
2. Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.3. Install the spark plug with the spark
plug wrench, and then tighten it to the
specified torque.
NOTE:
If a torque wrench is not available when
installing a spark plug, a good estimate of
the correct torque is 1/4–1/2 turn past fin-
ger tight. However, the spark plug should
be tightened to the specified torque as
soon as possible.
4. Install the spark plug cap.
5. Place the spark plug cover in the orig-
inal position.
6-6
6
a. Spark plug gap
To check the spark plugs
1. Check that the porcelain insulator
around the center electrode on each
spark plug is a medium-to-light tan
(the ideal color when the motorcycle
is ridden normally).
2. Check that all spark plugs installed in
the engine have the same color.
NOTE:
If any spark plug shows a distinctly differ-
ent color, the engine could be defective.
Do not attempt to diagnose such problems
yourself. Instead, have a Yamaha dealer
check the motorcycle.
3. Check each spark plug for electrode
erosion and excessive carbon or oth-
er deposits, and replace it if neces-
sary.
Specified spark plug:
BPR7ES (NGK) or
W22EPR-U (DENSO)
Tightening torque:
Spark plug:
20 Nm (2.0 m·kgf)
Spark plug gap:
0.7-0.8 mm
EAU00462PERIODIC MAINTENANCE AND MINOR REPAIR
EAU01297
Troubleshooting chart
EW000125WARNING0
Keep away open flames and do not smoke while checking or working on the fuel system.
6-36
6
Check the fuel level in the
fuel tank.
1. Fuel
2. Compression
3. Ignition
4. BatteryThere is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.The engine does not start. Check the compression.
There is compression.Check the ignition.
Have a Yamaha dealer check
the vehicle.
Wipe off with a dry cloth and correct the spark
plug gaps, or replace the spark plugs.Open the throttle halfway and operate the
electric starter.
Have a Yamaha dealer check
the vehicle.The engine does not start.
Check the battery.
The engine turns over slowly.
Have a Yamaha dealer check
the vehicle.
There is no compres-
sion.
Wet.
Dry
The engine turns over quickly.The battery is good.
Check the battery lead connections, and
charge the battery if necessary.The engine does not start.
Operate the electric
starter.
Remove the spark plugs
and check the electrodes.
Operate the electric
starter.
