Yamaha YZ450FX 2019 Owner's Service Manual page 294

CHECKING THE STARTER MOTOR OPERATION ................................8-64
CHECKING THE STATOR COIL..............................................................8-64
CHECKING THE RECTIFIER/REGULATOR ...........................................8-65
CHECKING THE FUEL SENDER ............................................................8-65
CHECKING THE RESISTOR ...................................................................8-65
CHECKING THE RADIATOR FAN MOTOR (For JPN) ............................8-66
CHECKING THE COOLANT TEMPERATURE SENSOR ........................8-66
CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE...8-67
CHECKING THE INTAKE AIR TEMPERATURE SENSOR .....................8-67
CHECKING THE GEAR POSITION SWITCH ..........................................8-68
CHECKING THE FUEL INJECTOR .........................................................8-68