Yamaha MX-800, Service Manual

Page: 153 / 188

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TR
OUBL
ESHOO
T
ING
6-1
TROUBLESHOOTING
ENGINE DOES NOT START
IGNITION SYSTEM
The ignition system fails to operate (no spark or intermittent spark).
No. Checking steps Possible remedy
1
Check the fuses.
(Refer to “CHECKING THE FUSES” on page 5-27)
Replace the fuse(s).
2 Check the battery.
• Clean the battery terminals.
• Recharge or replace the battery.
3
Check the spark plugs.
(Refer to “SPARK PLUGS” on page 2-2).
Re-gap or replace the spark plugs.
4
Check the ignition spark gap.
(Refer to “CHECKING THE IGNITION SPARK GAP” on
page 5-33)
If the ignition spark gap is OK, the igni-
tion system is OK.
5
Check the ignition coils.
(Refer to “CHECKING THE IGNITION COILS” on page
5-32)
Replace the ignition coils.
6
Check the spark plug cap resistance.
(Refer to “CHECKING THE SPARK PLUG CAPS” on page
5-33).
Replace the spark plug cap.
7
Check the crankshaft position sensor.
(Refer to “CHECKING THE CRANKSHAFT POSITION
SENSOR” on page 5-30)
Replace the crankshaft position sensor.
8 Check the main switch. Replace the main switch.
9
Check the entire ignition system’s wiring.
(Refer to “CIRCUIT DIAGRAM” on page 5-1) Properly connect or repair the ignition
system’s wiring.
10 Replace the ECU. —