Yamaha PW50W 2007 Service Manual page 155

TROUBLESHOOTING
The ignition system fails to operate (no
spark or intermittent spark).
Check:
1.Spark plug
2.Ignition spark gap
3.Spark plug cap resistance
4.Ignition coil resistance
5.Pickup coil resistance
6.Charge coil resistance
7.Lighting coil resistance
8.Ignition control switch
9.Control unit
10.Wiring connections (of the entire ignition
system)
NOTE:
9 Before troubleshooting, remove the follow-
ing part(s):
1.Seat
2.Front fender
9 Troubleshoot with the following special
tool(s).
Ignition checker
90890-06754, YM-06754
Pocket tester
90890-03112, YM-03112
1. Spark plug
9Check the condition of the spark plug.
9Check the spark plug type.
9Measure the spark plug gap.
Refer to "CHECKING THE SPARK PLUG"
in chapter 3.
Standard spark plug
NGK/BP4HS or DENSO/W14FPL
(Except for CANADA and
EUROPE)
NGK/BPR4HS
(For CANADA and EUROPE)
Spark plug gap
0.6–0.7 mm (0.024–0.028 in)
IGNITION SYSTEM
9Is the spark plug in good condition, is it of
the correct type, and is its gap within
specification?
YES
2. Ignition spark gap
9Disconnect the spark plug cap from the
spark plug.
9Connect the ignition checker 1 as shown.
2 Spark plug cap
9Set the main switch to "ON".
9Crank the engine by pushing the start
switch and gradually increase the spark
gap until a misfire occurs.
9Measure the ignition spark gap a.
Minimum ignition spark gap
6.0 mm (0.24 in)
9Is there a spark and is the spark gap within
specification?
NO
7-5
ELEC
NO
Re-gap or replace
the spark plug.
a
2
1
YES
The ignition system
is OK.