Yamaha YFM50S Service Manual page 214

EBS01040
7. Pickup coil resistance
• Disconnect the C.D.I. magneto coupler
from the wire harness.
• Connect the pocket tester (Ω × 100) to the
pickup coil terminal as shown.
Positive tester probe →
Negative tester probe →
white/blue terminal 2
G/W
W/L W/R
2
• Measure the pickup coil resistance.
Pickup coil resistance
264 ~ 396 Ω at 20 °C (68 °F)
(between white/red and white/
blue)
• Is the pickup coil OK?
YES
white/red terminal 1
B/R
1
NO
Replace the pickup
coil/stator assembly.
8 - 11
IGNITION SYSTEM
EBS01099
8. Source coil resistance
• Disconnect the C.D.I. magneto coupler
from the wire harness.
• Connect the pocket tester (Ω × 100) to the
source coil terminal.
Positive tester probe →
Negative tester probe →
green/white terminal 2
2
G/W
W/L W/R
• Measure the source coil resistance.
Source coil resistance
304 ~ 456 Ω at 20 °C (68 °F)
(black/red and green/white)
YES
EBS01047
9. Wiring
• Check the entire ignition system's wiring.
Refer to "CIRCUIT DIAGRAM".
• Is the ignition system's wiring properly
connected and without defects?
YES
Replace the C.D.I.
unit.
– +
ELEC
black/red terminal 1
1
B/R
NO
Replace the pickup
coil/stator assembly.
NO
Properly connect or
repair the ignition
system's wiring.