2013 YAMAHA YZ450F fuel pressure

6-4
THROTTLE BODY
THROTTLE BODY
REMOVING THE THROTTLE BODY
Order Part name Q'ty Remarks
SeatRefer to "SEAT AND SIDE COVERS" section
in the chapter 4.
Air scoop (left/right)Refer to "SEAT AND SIDE COVERS" section
in the chapter 4.
Fuel tank Refer to "FUEL TANK" section.
1 Cover 1
2 Air filter case 1
3 Fuel hose 1
4 Fuel injector coupler 1 Disconnect.
5 Intake air pressure sensor coupler 1 Disconnect. (I.D. MARK "2")
6 Throttle cable cover 1
7 Throttle cable 2
8 Throttle body 1
9 Throttle body joint 1

6-6
THROTTLE BODY
CHECKING THE INJECTOR
Replace the fuel injector with a
new one if you have dropped or im-
pacted it.
1. Check:
• Injectors
Damage → Replace.
CHECKING THE THROTTLE BODY
•Before removing the throttle
body, clean the area around the
throttle body to prevent dirt and
other foreign material from fall-
ing into the engine.
•If the throttle body is subject to
strong shocks or dropped during
cleaning, replace it.
•Do not use any caustic carbure-
tor cleaning solution.
•Do not directly push the throttle
valves to open them.
•Do not loosen the throttle valve
stopper screw "1", throttle valve
pulley nut "2", or throttle valve
screw "3". Otherwise, a loss of
performance may occur.
•Do not use compressed air to
clean the throttle body. Other-
wise, foreign material may ad-
here to the intake air pressure
sensor passage "a" and fuel in-
jector "b" in the throttle body.
1. Check:
• Throttle body
Cracks/damage → Replace the
throttle body as a set.
2. Check:
• Starter knob/ idle screw delivery
passages "a"
Obstructions →Blow out with
compressed air.
ASSEMBLING THE THROTTLE
BODY
1. Install:
• O-ring "1"
• Injector "2"
•Bolt "3"
Always use a new O-ring.
INSTALLING THE THROTTLE
BODY
1. Install:
• Throttle body joint "1"
• Throttle body "2"
• Face the slot "a" in the throttle body
joint toward the bottom of the vehi-
cle.
•Align the slot "a" on the throttle body
joint with the projection "b" on the
throttle body.
2. Install the water-resistant cover
"1" onto the throttle body.
CHECKING AND REPLACING THE
PROTECTOR
1. Check:
• Protector "1"
Wear/damage → Replace.
Affix the protector as shown.Bolt (injector)
3 Nm (0.3 kg•m, 2.2
ft•lb)
Throttle body joint clamp
screw
3 Nm (0.3 m•kg, 2.2
ft•lb)

7-1
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Condenser
5. Fuel pump
6. Engine stop switch
7. ECU
8. Ignition coil9. Spark plug
10. Fuel injector
11. Intake air temperature sensor
12. Intake air pressure sensor
13. Throttle position sensor
14. Atmospheric pressure sensor
15. Coolant temperature sensor
16. Coupler for connecting optional part
7

7-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
WIRING DIAGRAM
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Condenser
5. Fuel pump
6. Engine stop switch
7. ECU
8. Ignition coil
9. Spark plug
10. Fuel injector
11. Intake air temperature sensor
12. Intake air pressure sensor
13. Throttle position sensor
14. Atmospheric pressure sensor
15. Coolant temperature sensor
16. Coupler for connecting optional part COLOR CODE
BBlack
Br Brown
Gy Gray
LBlue
Lg Light green
O Orange
PPink
RRed
WWhite
YYellow
B/L Black/Blue
B/R Black/Red
B/W Black/White
B/Y Black/Yellow
Br/W Brown/White
P/W Pink/White
R/B Red/Black
R/W Red/White
STOPON
Gy
Gy
B
B/L
W1
W2
W2 O
R/B
R RR
R
R
R R
Lg
Lg Lg L
P/W
P
YB/RB
B B
BB BB
BB/W
B/W B/W Br/WGyB/L
W1 W1
W2 W2 B/Y
B/Y Br
B/R
R/W
OO
R/B RR
R
L
P/W
PYL
L
LY
Br/WB/L
B/L B/L
B
B/L
B/L
Br
W1
Br/W
W2
R
R O
B/L
L
Y
B/L
Br
R
P
Gy
Gy
B/R
B/R
R/WB/Y
B/L
W1
W2
W1 R
R R
B
B/Y
Lg Lg
O
R/B R/B
Br/W
P/W P/W
LL
Y
B/L B/L
B/L
Br
B
B/W
B/W
B
B
B L
B/L P

7-11
FUEL INJECTION SYSTEM
SENSOR OPERATION TABLE
Diagnos-
tic code
No.ItemActuation or
displayChecking methodActuation or LCD standard display
values
D01 Throttle angle DisplayDisplays the throttle angle. 0–125°
Check with throttle fully closed. When throttle is fully closed:15–19°
Check with throttle fully open. When throttle is fully opened:95–
101 °
D02 Atmosphere DisplayDisplays the atmospheric pres-
sure.
• Measure the atmospheric pres-
sure.0–126 kPa
Displays the atmospheric pressure
according to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
D03 Intake air pressure DisplayDisplays the intake air pressure.
• Check the intake manifold pres-
sure.
• Check that the intake air pres-
sure changes while the engine is
being cranked.0–126 kPa
While the engine is stopped: Dis-
plays the atmospheric pressure ac-
cording to the elevation and
weather.
Example
0 m above sea level: Approx: 101
kPa
3000 m above sea level:Approx: 70
kPa
While the engine is being cranked:
Displays the intake air pressure.
D05 Intake air temperature DisplayDisplays the intake air tempera-
ture.
• Check the temperature in the in-
take manifold.-20–100°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is approximately 20 °C higher
than the ambient temperature.
D06 Coolant temperature DisplayDisplays the coolant temperature.
• Check the coolant temperature.-20–150°C
Cold engine: Displayed tempera-
ture is close to the ambient temper-
ature.
Warm engine: Displayed tempera-
ture is the current coolant tempera-
ture.
D08 Lean angle sensor DisplayDisplays the lean angle sensor
output voltage.
Remove the ECU and incline it 45°
or more.0–5.0 V
1.0 V: Upright
4.0 V: Overturned
D30 Ignition coil ActuationCheck that power is supplied to
the ignition coil.
• Check that a spark is generated.
• Illuminates the engine trouble
warning light.Actuates the ignition coil for five
times every second.
The "WARNING" LED on the FI di-
agnostic tool comes on each time
the fuel injector is actuated.

7-14
FUEL INJECTION SYSTEM
If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault code No. 13 first.
5 Defective crankshaft position sensor. Sensor malfunction → Replace.
Refer to "CHECKING THE AC
MAGNETO" section.Crank the engine and
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
6.
6 Malfunction in ECU. Replace the ECU.
Fault code No. 13
Symptom Intake air pressure sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D03
FI diagnostic tool display Intake air pressure
Checking method Crank the engine. (If the display value changes, the performance is OK.)
Item Item/components and probable cause Check or maintenance job Checking method
1 Check the connection and locking condition of
the intake air pressure sensor coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)Poor connection → Properly con-
nect, repair, or replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 2.
2 Check the connection and locking condition of
the wire harness ECU coupler.
Disconnect the coupler and check the pins.
(bent or broken terminals and locking condition
of the pins)Poor connection → Properly con-
nect, repair, or replace.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 3. Fault code No. 12
Symptom No normal signals are received from the crankshaft position sensor.
Fail-safe system Able to start
Able to drive
Diagnostic code No. —
FI diagnostic tool display —
Checking method —
Item Item/components and probable cause Check or maintenance job Checking method

7-15
FUEL INJECTION SYSTEM
3 Continuity of harness Open or short circuit → Replace.
Between the intake air pressure
sensor coupler and ECU coupler.
(Black/Blue–Black/Blue)
(Pink/White–Pink/White)
(Blue–Blue)Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 4.
4 Installed condition of sensor.
Make sure that the installation position is cor-
rect.Check that the sensor is installed
securely and that there are no
pinched leads.Check that the ECU
is installed securely and that there
are no pinched leads.
Incorrect installation → Reinstall
or repair.
Incorrect installation position →
Properly install.Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 5.
5 Defective intake air pressure sensor. Execute the diagnostic mode (di-
agnostic code No. D03).
When the engine is stopped,
displays the atmospheric pres-
sure according to the elevation
and weather.
0 m above sea level: Approx.
101 kPa
1000 m above sea level: Ap-
prox. 90 kPa
2000 m above sea level: Ap-
prox. 80 kPa
3000 m above sea level: Ap-
prox. 70 kPa
Check that the value changes
while the engine is being
cranked.
Displayed value is incorrect → Re-
place. Set the switch on the FI di-
agnostic tool sub-wire har-
ness to "ON", and then
check the fault code dis-
play.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item 6.
6 Malfunction in ECU. Replace the ECU. Fault code No. 13
Symptom Intake air pressure sensor signal is not received properly.
Fail-safe system Able to start
Able to drive
Diagnostic code No. D03
FI diagnostic tool display Intake air pressure
Checking method Crank the engine. (If the display value changes, the performance is OK.)
Item Item/components and probable cause Check or maintenance job Checking method

7-16
FUEL INJECTION SYSTEM
If fault code Nos. 13 and 14 are both displayed, perform the checks and maintenance jobs for fault code No. 13 first.
Fault code No. 14
SymptomIntake air pressure sensor system malfunction detected. (clogged hole or disconnected
sensor)
Fail-safe system Able to start
Able to drive
Diagnostic code No. D03
FI diagnostic tool display Intake air pressure
Checking method Crank the engine. (If the display value changes, the performance is OK.)
Item Item/components and probable cause Check or maintenance job Checking method
1 Intake air pressure sensor hose is clogged,
damaged, disconnected, kinked, pinched, or
twisted.Repair or replace. Start the engine and let it
idle for approximately 5
seconds with the throttle
fully closed.
After completing the above
operation, check whether a
fault code number is dis-
played.
Fault code number is not
displayed → Service is
finished.
Fault code number is dis-
played → Refer to item
2.
2 Defective intake air pressure sensor. Execute the diagnostic mode (di-
agnostic code No. D03).
When the engine is stopped,
displays the atmospheric pres-
sure according to the elevation
and weather.
0 m above sea level: Approx.
101 kPa
1000 m above sea level: Ap-
prox. 90 kPa
2000 m above sea level: Ap-
prox. 80 kPa
3000 m above sea level: Ap-
prox. 70 kPa
Display value does not change→
Replace the sensor.