Yamaha YXR70FX Service Manual page 441

EBS01032
3. Spark plug
• Check the condition of the spark plug.
• Check the spark plug type.
• Measure the spark plug gap.
Refer to "CHECKING THE SPARK PLUG"
in chapter 3.
Standard spark plug
CPR7EA-9 (NGK)
Spark plug gap
0.8 ~ 0.9 mm (0.031 ~ 0.035 in)
• Is the spark plug in good condition, is it of
the correct type, and is its gap within spec-
ification?
YES
NO
Re-gap or replace
the spark plug.
9 - 11
IGNITION SYSTEM
EBS01034
4. Ignition spark gap
• Disconnect the spark plug cap from the
spark plug.
• Connect the ignition checker 1 as shown.
2 Spark plug cap
• Measure the ignition spark gap a.
• Crank the engine by setting the main
switch to "START" and gradually increase
the spark gap until a misfire occurs.
Minimum ignition spark gap
6.0 mm (0.24 in)
• Is there a spark and is the spark gap within
specification?
NO
– +
ELEC
YES
The ignition system
is OK.