sensor YAMAHA YZ450F 2014 User Guide

AC MAGNETO
5-59
EAS1SL1272
AC MAGNETO
Removing the AC magneto
OrderPart nameQ’tyRemarks
Engine oilDrain.Refer to “CHANGING THE ENGINE OIL” on page 3-15.
SeatRefer to “GENERAL CHASSIS” on page 4-1.
Air scoop (left)Refer to “GENERAL CHASSIS” on page 4-1.
1AC magneto leadDisconnect.
2Crankshaft position sensor lead1Disconnect.
3Shift pedal1
4Left crankcase cover1
5Gaskets1
6Dowel pin2
7Holder1
8Stator assembly1
9Rotor1
10Woodruff key1
For installation, reverse the removal proce-dure.
110
2
4 7 5 8 3
96
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
8 Nm (0.8 mkgf, 5.8 ftIbf)T.R.
8 Nm (0.8 mkgf, 5.8 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
65 Nm (6.5 mkgf, 47 ftIbf)T.R.
New
LT
6
LT
LT

AC MAGNETO
5-60
EAS1SL1273REMOVING THE AC MAGNETO
1. Remove:
• Nut (rotor) “1”
• Washers
2. Remove:
• Rotor “1”
Use the rotor puller “2” to remove the rotor.
• Woodruff key
EAS1SL1274CHECKING THE AC MAGNETO
1. Check:
• Rotor inner surface “a”
• Stator outer surface “b”
Damage  Inspect the crankshaft runout
and crankshaft bearing.
EAS1SL1275
CHECKING THE WOODRUFF KEY
1. Check:
• Woodruff key “1”
Damage  Replace.
EAS1SL1276INSTALLING THE AC MAGNETO
1. Install:
• Stator “1”
• Screw (stator) “2”
• Crankshaft position sensor “3”
• Bolt (crankshaft position sensor) “4”
• Holder “5”
• Bolt (holder) “6”
TIP
• Apply the sealant to the grommet of the AC
magneto lead.
• Tighten the stator screws using the T25 bit.
• Pass the AC magneto lead “a” through the
crankcase cover side.
Rotor puller
90890-04151
YM-04151
1
ab
Screw (stator)
8 Nm (0.8 m·kgf, 5.8ft·lbf)
LOCTITE®
Bolt (crankshaft position sensor)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
LOCTITE®
Holder
8 Nm (0.8 m·kgf, 5.8 ft·lbf)
LOCTITE®
Three Bond No.1215®
90890-85505
T R..
T R..
26
5
4
3
4a
1
LT
LT

RADIATOR
6-2
4Radiator hose 21
5Radiator hose 31
6Radiator hose 41
7Radiator pipe 21
8Radiator breather hose1
9Left radiator1
10Radiator hose 11
11Radiator pipe 11
12Coolant temperature sensor1
For installation, reverse the removal proce-dure.
Removing the radiator
Order Part name Q’ty Remarks
11
12
New
New
New
LS
LS

7
FUEL SYSTEM
FUEL TANK...................................................................................................... 7-1
REMOVING THE FUEL TANK ................................................................... 7-2
REMOVING THE FUEL PUMP .................................................................. 7-2
CHECKING THE FUEL PUMP BODY........................................................ 7-2
INSTALLING THE FUEL PUMP ................................................................. 7-2
INSTALLING THE FUEL TANK.................................................................. 7-3
CHECKING THE FUEL PRESSURE ......................................................... 7-3
CHECKING THE DAMPER ........................................................................ 7-4
CHECKING AND REPLACING THE PROTECTOR .................................. 7-4
THROTTLE BODY............................................................................................ 7-5
CHECKING THE INJECTOR ..................................................................... 7-8
CHECKING THE THROTTLE BODY ......................................................... 7-8
CHECKING THE THROTTLE BODY JOINT .............................................. 7-8
ADJUSTING THE THROTTLE POSITION SENSOR................................. 7-9

THROTTLE BODY
7-5
EAS1SL1314
THROTTLE BODY
Removing the throttle body
OrderPart nameQ’tyRemarks
SeatRefer to “GENERAL CHASSIS” on page 4-1.
Side cover (left/right)Refer to “GENERAL CHASSIS” on page 4-1.
Air scoop (left/right)Refer to “GENERAL CHASSIS” on page 4-1.
Fuel tankRefer to “FUEL TANK” on page 7-1.
ECURefer to “ENGINE REMOVAL” on page 5-1.
Ignition coilRefer to “ENGINE REMOVAL” on page 5-1.
1Intake air temperature sensor coupler1Disconnect.
2Air filter case1
3Fuel injector coupler1Disconnect.
4Intake air pressure sensor coupler1Disconnect.
5Throttle position sensor coupler1Disconnect.
6Throttle cable cover1
7Throttle cable2
8Fuel hose1
9Exhaust pipe bracket1
2
1
6
10
11
9
8
3
7
5
4
3.5 Nm (0.35 mkgf, 2.5 ftIbf)T.R.
3.5 Nm (0.35 mkgf, 2.5 ftIbf)T.R.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
3.0 Nm (0.30 mkgf, 2.2 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.

THROTTLE BODY
7-7
Removing the injector
OrderPart nameQ’tyRemarks
1Fuel inlet pipe1
2Injector1
3Gaskets1
4Throttle position sensor1
5Intake air pressure sensor1
For installation, reverse the removal proce-dure.
1
2 (2)
(2)5
43
T.R.3.4 Nm (0.34 mlbf) kgf, 2.5 ft
T.R.5 Nm (0.5 mlbf) kgf, 3.6 ft
T.R.3.4 Nm (0.34 mlbf) kgf, 2.5 ft

THROTTLE BODY
7-8
EAS1SL1315CHECKING THE INJECTOR
1. Check:
• Injector
Obstruction  Replace, and check the fuel
pump and the fuel injection system.
Refer to “FUEL INJECTION SYSTEM” on
page 8-10.
Deposits  Replace.
Damage  Replace.
2. Check:
• Injector resistance
Refer to “CHECKING THE FUEL INJEC-
TOR” on page 8-47.
EAS1SL1316CHECKING THE THROTTLE BODY
1. Check:
• Throttle body
Cracks/damage  Replace.
2. Check:
• Fuel passages
Obstructions  Clean.ECA1DX1027
NOTICE
• Before removing the throttle body, clean
the area around the throttle body to pre
-
vent dirt and other foreign material from
falling into the engine.
• If the throttle body is subject to strong
shocks or dropped during cleaning, re
-
place it.
• Do not use any caustic carburetor clean-
ing 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”. A loss of perfor
-
mance may occur.
• Do not use compressed air to clean the
throttle body. Foreign materials may ad
-
here to the intake air pressure sensor pas-
sage “a” and fuel injector “b” in the
throttle body.
3. Check:
• Starter knob/idle screw passage “c”
Obstruction  Blow out with compressed
air.
EAS1SL1317CHECKING THE THROTTLE BODY JOINT
1. Check:
• Throttle body joint “1”
Crack/damage  Replace.
EAS1SL1318
1 2
3
ba
c
1

THROTTLE BODY
7-9
ADJUSTING THE THROTTLE POSITION
SENSOR
EWA32D1011
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” on page 8-44.
2. Adjust:
• Throttle position sensor angle
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Connect the Yamaha diagnostic tool.
Refer to “YAMAHA DIAGNOSTIC TOOL” on
page 8-12.
b. Temporary tighten the throttle position sen-
sor.
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 “diagnos-
tic mode”.
f. Choose the diagnostic code No. “01”.
g. Adjust the throttle position sensor mounted
angle until “11-14” appears on the Yamaha
diagnostic tool.
h. After adjusting the throttle position sensor
mounted angle, tighten the throttle position
sensor screws “1”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
Yamaha diagnostic tool
90890-03215
Throttle position sensor screw
3.4 Nm (0.34 m·kgf, 2.5 ft·lbf)T R..
1

8
ELECTRICAL SYSTEM
IGNITION SYSTEM.......................................................................................... 8-2
CIRCUIT DIAGRAM ................................................................................... 8-2
TROUBLESHOOTING ............................................................................... 8-4
CHARGING SYSTEM....................................................................................... 8-6
CIRCUIT DIAGRAM ................................................................................... 8-6
TROUBLE SHOOTING .............................................................................. 8-8
FUEL INJECTION SYSTEM........................................................................... 8-10
CIRCUIT DIAGRAM ................................................................................. 8-10
YAMAHA DIAGNOSTIC TOOL ................................................................ 8-12
TROUBLESHOOTING DETAILS ............................................................. 8-13
FUEL PUMP SYSTEM.................................................................................... 8-32
CIRCUIT DIAGRAM ................................................................................. 8-32
TROUBLESHOOTING ............................................................................. 8-34
ELECTRICAL COMPONENTS....................................................................... 8-36
CHECKING THE SWITCHES .................................................................. 8-38
CHECKING THE IGNITION SPARK GAP................................................ 8-41
CHECKING THE SPARK PLUG CAP ...................................................... 8-41
CHECKING THE IGNITION COIL ............................................................ 8-41
CHECKING THE CRANKSHAFT POSITION SENSOR........................... 8-42
CHECKING THE ECU .............................................................................. 8-43
CHECKING THE STATOR COIL ............................................................. 8-43
CHECKING THE RECTIFIER/REGULATOR ........................................... 8-43
CHECKING THE COOLANT TEMPERATURE SENSOR........................ 8-44
CHECKING THE THROTTLE POSITION SENSOR ................................ 8-44
CHECKING THE THROTTLE POSITION SENSOR 
INPUT VOLTAGE .................................................................................... 8-43
CHECKING THE INTAKE AIR PRESSURE SENSOR ............................ 8-46
CHECKING THE INTAKE AIR TEMPERATURE SENSOR ..................... 8-46
CHECKING THE NEUTRAL SWITCH ..................................................... 8-46
CHECKING THE FUEL INJECTOR ......................................................... 8-47

IGNITION SYSTEM
8-3
EAS1SL1322
1. Crankshaft position sensor
2. AC magneto
3. Rectifier/regulator
4. Joint connector
5. Condenser
7. Engine stop switch
9. ECU
10.Ignition coil
11.Spark plug