Checking The Ignition Coil; Checking The Ignition Spark Gap - Yamaha YFM70RY Service Manual

b. Connect the pocket tester (Ω × 1k) to the
spark plug cap as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
c. Measure the spark plug cap resistance.
L LLL L LLL L L LLL L
EAS28090

CHECKING THE IGNITION COIL

1. Check:
• Primary coil resistance
Out of specification → Replace.
Primary coil resistance
3.40–4.60 Ω at 20 °C (68 °F)
M MMM M MMM M M MMM M
a. Disconnect the ignition coil connectors from
the ignition coil terminals.
b. Connect the pocket tester (Ω × 1) to the igni-
tion coil as shown.
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe
red/black "1"
• Negative tester probe
orange "2"
L LLL L L LLL L L LLL L
M MMM M M MMM M M MMM M
ELECTRICAL COMPONENTS
c. Measure the primary coil resistance.
L LLL L LLL L
2. Check:
• Secondary coil resistance
Out of specification → Replace.
M MMM M MMM M
a. Disconnect the spark plug cap from the igni-
tion coil.
b. Connect the pocket tester (Ω × 1k) to the ig-
nition coil as shown.
LLL
• Positive tester probe
red/black "1"
• Negative tester probe
Spark plug lead "2"
MMM
c. Measure the secondary coil resistance.
L LLL L LLL L
EAS28930

CHECKING THE IGNITION SPARK GAP

1. Check:
• Ignition spark gap
Out of specification → Perform the ignition
system troubleshooting, starting with step 5.
Refer to "TROUBLESHOOTING" on page
8-3.
TIP
If the ignition spark gap is within specification,
the ignition system circuit is operating normally.
8-67
L LLL L L LLL L L LLL L
Secondary coil resistance
10.40–15.60 kΩ at 20 °C (68 °F)
M MMM M M MMM M M MMM M
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
L LLL L L LLL L L LLL L
Minimum ignition spark gap
6.0 mm (0.24 in)
L LLL L LLL
M MMM M MMM
L LLL L LLL