Yamaha CS50 Service Manual page 169

EAS00744
3. Spark plug cap resistance
• Remove the spark plug cap from the spark
plug lead.
• Connect the pocket tester ("Ω x 1k" range)
to the spark plug cap as shown.
• Measure the spark plug cap resistance.
Spark plug cap resistance
10KΩ at 20°C
• Is the spark plug cap OK?
YES
EAS00746
4. Ignition coil resistance
• Disconnect the ignition coil connectors
from the ignition coil terminals.
• Connect the pocket tester (Ω x 1) to the
ignition coil as shown.
Positive tester probe
Negative tester probe
• Measure the primary coil resistance.
Primary coil resistance
0.56 ~ 0.84 at 20°C
NO
Replace the spark
plug cap.
red/black
orange (gray)
IGNITION SYSTEM
• Connect the pocket tester (Ω x 1k) to the
ignition coil as shown.
Negative tester probe
Positive tester probe
• Measure the secondary coil resistance.
Secondary coil resistance
5.68 ~ 8.52 kΩ at 20°C
• Is the ignition coil OK?
YES
EAS00749
5. Main switch
• Check the main switch for continuity.
Refer to "CHECKING THE SWITCHES".
• Is the main switch OK?
YES
8-10
ELEC
spark plug lead
ground
NO
Replace the ignition
coil.
NO
Replace the main
switch.