Checking The Fuel Pressure; Adjusting The Throttle Position Sensor - Yamaha YZ450FP 2023 Owner's Service Manual

EAM30268

CHECKING THE FUEL PRESSURE

1. Check:
• Fuel pressure
a. Remove the side cover (left/right), the seat
and the shroud (left/right).
Refer to "GENERAL CHASSIS" on page
4-1.
b. Remove the fuel tank bolt and lift the fuel
tank.
c. Disconnect the fuel hose from the fuel
pump.
Refer to "REMOVING THE FUEL TANK"
on page 7-2.
EWA19380
WARNING
Cover the fuel hose connection with a cloth
when disconnecting it. This is because re-
sidual pressure in the fuel hose could cause
fuel to spurt out when the hose is removed.
ECA24750
NOTICE
Make sure that the fuel hose is disconnected
by hand. Do not forcibly disconnect the hose
with tools.
d. Connect the pressure gauge "1" and the
fuel pressure adapter "2" to the fuel hose.
Pressure gauge
90890-03153
Pressure gauge
YU-03153
Fuel pressure adapter
90890-03186
Fuel pressure adapter
YM-03186
1 1 1
e. Start the engine.
f. Measure the fuel line pressure.
Out of specification  Replace the fuel
pump.
2 2
7-8
THROTTLE BODY
Fuel line pressure (at idle)
300–390 kPa (3.0–3.9 kgf/cm²,
43.5–56.6 psi)
EAM30273
ADJUSTING THE THROTTLE POSITION
SENSOR
EWA15950
WARNING
• Handle the throttle position sensor with
special care.
• Never subject the throttle position sensor
to strong shocks. If the throttle position
sensor is dropped, replace it.
1. Check:
• Throttle position sensor
Refer to "CHECKING THE THROTTLE PO-
SITION SENSOR INPUT VOLTAGE" on
page 8-53.
2. Adjust:
• Throttle position sensor angle
a. Connect the Yamaha diagnostic tool.
Refer to "YAMAHA DIAGNOSTIC TOOL"
on page 8-17.
Yamaha diagnostic tool USB (US)
90890-03269
Yamaha diagnostic tool (A/I)
90890-03264
b. Temporary tighten the throttle position
sensor.
c. Check that the throttle grip is fully closed.
d. Connect the throttle position sensor to the
wire harness.
e. Set the Yamaha diagnostic tool to "diag-
nostic mode".
f. Choose the diagnostic code No. "01".
g. Adjust the throttle position sensor mount-
ed angle until "11"–"14" appears on the
Yamaha diagnostic tool.
h. After adjusting the throttle position sensor
mounted angle, tighten the throttle posi-
tion sensor screw "1".
Throttle position sensor screw
3.5 N·m (0.35 kgf·m, 2.6 lb·ft)