Yamaha WR450FN 2022 Owner's Service Manual page 309

9. Check the start switch.
Refer to "CHECKING THE
SWITCHES" on page 8-57.
OK
10.Check the entire starting system's
wiring.
Refer to "CIRCUIT DIAGRAM" on
page 8-5.
OK
Replace the ECU.
ELECTRIC STARTING SYSTEM
Replace the start switch.
NG
Properly connect or repair the starting sys-
tem's wiring.
NG
8-10