Yamaha YZ250F(E), Owner'S Service Manual

Page: 290 / 356

IGNITION SYSTEM
8-4
TROUBLESHOOTING
The ignition system fails to operate (no spark or intermittent spark).
TIP
Before troubleshooting, remove the following part(s):
1. Side cover (left/right)
2. Seat
3. Fuel tank
4. Air scoop (left/right)
5. Air filter case cover
1. Check the ignition system wire har-
ness connections.
NG

Reconnect.
OK

2. Check the spark plug.
Refer to “CHECKING THE SPARK
PLUG” on page 3-35.
NG

Correct or replace the spark plug.
OK

3. Check the ignition spark gap.
Refer to “CHECKING THE IGNI-
TION SPARK GAP” on page 8-41.
OK

The ignition system circuit is OK.
NG

4. Check the ignition coil.
Refer to “CHECKING THE IGNI-
TION COIL” on page 8-41.
NG

Replace the ignition coil.
OK

5. Check the engine stop switch.
Refer to “CHECKING THE
SWITCHES” on page 8-38.
NG

Replace the engine stop switch.
OK

6. Check the crankshaft position sen-
sor.
Refer to “CHECKING THE CRANK-
SHAFT POSITION SENSOR” on
page 8-42.
NG

Replace the crankshaft position sensor.
OK

7. Check the stator coil.
Refer to “CHECKING THE STA-
TOR COIL” on page 8-43.
NG

Replace the stator coil.
OK
