2014 YAMAHA YZ450F air filter

DESCRIPTION
1-4
EAS1SL1009
DESCRIPTION
TIP
Designs and specifications of the vehicle are subject to change without notice. Therefore, please
note that the descriptions in this manual may be different from those for the vehicle you have pur
-
chased.
1. Clutch lever10. Coolant drain bolt
2. Front brake lever11. Rear brake pedal
3. Throttle grip12. Air filter
4. Radiator cap13. Drive chain
5. Fuel tank cap14. Shift pedal
6. Engine stop switch15. Oil level check window
7. Fuel tank16. Starter knob/idle screw
8. Kickstarter lever17. Front fork
9. Radiator
2 1
6
78 954 3
11 10 17 16 15 14 1312

FEATURES
1-7
FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 324 kPa (3.24 kgf/cm², 47.0 psi). Accordingly,
when the energizing signal from the ECU energizes the fuel injector, the fuel passage opens, causing
the fuel to be injected into the intake manifold only during the time the passage remains open. There
-
fore, the longer the length of time the fuel injector is energized (injection duration), the greater the
volume of fuel that is supplied. Conversely, the shorter the length of time the fuel injector is energized
(injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals input from the throt-
tle position sensor, the coolant temperature sensor, the crankshaft position sensor, the intake air
pressure sensor, and the intake air temperature sensor enable the ECU to determine the injection
duration. The injection timing is determined through the signals from the crankshaft position sensor.
As a result, the volume of fuel that is required by the engine can be supplied at all times in accordance
with the driving conditions.
1. Fuel pump
2. Fuel injector
3. ECU
4. Throttle position sensor
5. Coolant temperature sensor
6. Crankshaft position sensor
7. Intake air pressure sensor
8. Throttle body
9. Intake air temperature sensor
10.Air filter case
A. Fuel system
B. Intake system
C. Control system
1
234
5
6 7
8 9 10A
BC

STARTING AND BREAK-IN
1-23
7. To stop the engine, push the engine stop
switch “1.”
TIP
Continue pushing the engine stop switch till the
engine comes to a full stop.
EAS1SL1044STARTING A WARM ENGINE
When the engine is warm, give a kick with the
throttle closed without using the starter knob/
idle screw.
TIP
If it fails to start, fully open the throttle grip and
give 10 to 20 slow kicks to clear the engine of
the rich air-fuel mixture retained in it.
EAS1SL1045BREAK-IN PROCEDURES
A break-in is important so that rotating portion,
sliding surfaces, and mounted areas may fit
one another, and that the rider may become ac
-
customed to the machine.ECA
NOTICE
Before running, do maintenance on the air
filter element.
Refer to “CLEANING THE AIR FILTER ELE-
MENT” on page 3-12.
1. After warming up the engine, drive it for
about 20 minutes at a throttle opening of 1/2
or less.
2. Make a pit stop, and check mounted areas
for looseness, oil leaks, or other problems.
3. Then, drive it for about 40 minutes at a throt-
tle opening of 3/4 or less.
4. Make a pit stop again, and thoroughly check
mounted areas for looseness, oil leaks, or
other problems. Thorough checks and ad
-
justments are required in particular for
stretch of cables, free play of the brake,
stretch of the drive chain, looseness of the
spoke, and so on.
ECA
NOTICE
After a break-in or after each race, always
check the points shown in “TORQUE-
CHECK POINTS” for tightening torques and
retighten them. (
“TORQUE-CHECK
POINTS” on page 1-25) 
Also when the following parts are replaced,
a break-in is required.
• Cylinder and Crankshaft: A break-in is re-
quired for about an hour.
• Piston, Piston ring, Valve, Camshaft, and
Gear: A break-in is required for about 30
minutes at a throttle opening of 1/2 or less.
Observe the condition of the engine careful-
ly during a break-in. 
For checkpoints for a break-in, see “MAIN-
TENANCE AFTER BREAK-IN.” If any prob-
lem is found, immediately stop the engine
and make a checkup.
EAS1SL1046

ENGINE SPECIFICATIONS
2-7
Shifting mechanism
Shift mechanism type Shift drum and guide bar
Shift fork guide bar bending limit 0.050 mm (0.0020 in)
Shift fork thickness 4.85 mm (0.1909 in)
Decompression device
Device type Auto decomp
Air filter
Air filter element Wet element
Air filter oil grade Foam air-filter oil
Fuel pump
Pump type Electrical
Fuel injector
Model/quantity 1010/1
Resistance 12 
Throttle body
Type/quantity 30RA-A13M/1
ID mark 1SL1 00
Fuel pressure 324.0 kPa (3.24 kgf/cm2, 47.0 psi)
Throttle position sensor
Resistance 6.30 k
Output voltage (at idle) 0.48–0.52 V
Fuel injection sensor
Crankshaft position sensor resistance 248–372 
Intake air pressure sensor output voltage 3.57–3.71 V at 101.3 kPa
Intake air temperature sensor resistance 290–390  at 80 °C (176 °F)
Coolant temperature sensor resistance 2.51–2.78 k at 20°C (68°F)
210–221  at 100°C (212°F)
Idling condition
Engine idling speed 1900–2100 r/min
CO% 6.8–9.2 %
Intake vacuum 30.5–37.8 kPa (229–284 mmHg, 
9.0–11.2 inHg)
Water temperature 70–80 °C (158–176 °F)
Oil temperature 55-65 °C (131–149 °F)
Throttle grip free play 3.0–5.0 mm (0.12–0.20 in)

TIGHTENING TORQUES
2-14
EAS1SL1057ENGINE TIGHTENING TORQUES
TIP
- marked portion shall be checked for torque tightening after break-in or before each race.
ITEMThread
sizeQ’tyTIGHTENING TORQUESRemarks
Camshaft cap boltM6810 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder head blind plugM12128 Nm (2.8 m·kgf, 20 ft·lbf)
Spark plugM10113 Nm (1.3 m·kgf, 9.4 ft·lbf)
Cylinder head stud bolt (exhaust
pipe)M637 Nm (0.7 m·kgf, 5.1 ft·lbf)
Cylinder head boltsM94See TIP.*1
Cylinder head boltsM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder head cover boltM6310 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil passage plug (cylinder head)M8115 Nm (1.5 m·kgf, 11 ft·lbf)
Cylinder boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil pressure check boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Balancer weight plate screwM6310 Nm (1.0 m·kgf, 7.2 ft·lbf)
Balancer driven gear nutM14150 Nm (5.0 m·kgf, 36 ft·lbf)
Use a
lock
washer.
Balancer nutM10145 Nm (4.5 m·kgf, 33 ft·lbf)
Use a
lock
washer.
Timing chain guide stopper plate
(exhaust side)M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Timing chain tensioner cap boltM616 Nm (0.6 m·kgf, 4.3 ft·lbf)
Timing chain tensioner boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Coolant drain boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator hose clamp screwM681.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Radiator boltM6410 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator pipe bolt M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator pipe joint bolt M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Water pump housing cover boltM6410 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil pump boltM525 Nm (0.5 m·kgf, 3.6 ft·lbf)
Oil pump cover screwM412.0 Nm (0.20 m·kgf, 1.4 ft·lbf)
Oil strainer boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil passage cover bolt (left crank-
case)M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Throttle cable cover boltM513.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Throttle body joint boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Throttle body joint clamp boltM513.0 Nm (0.30 m·kgf, 2.2 ft·lbf)
Air filter joint clamp boltM413.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Air filter case boltM637 Nm (0.7 m·kgf, 5.1 ft·lbf)
LT
M
LT
LT
LT

TIGHTENING TORQUES
2-15
Air filter boltM6 1 2.0 Nm (0.20 m·kgf, 1.4 ft·lbf)
Air filter case cover bolt M6 3 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Air filter guide holder screw M5 8 2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Air filter case cap screw M5 1 2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Starter knob/Idle screw M12 1 2.1 Nm (0.21 m·kgf, 1.5 ft·lbf)
Throttle cable nut (pull) M10 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Throttle cable nut (return) M10 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Clutch cable adjuster and locknut M6 1 4.3 Nm (0.43 m·kgf, 3.1 ft·lbf)
Clutch cable locknut (engine side) M8 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Exhaust pipe nut M6 3See TIP.
*2
Exhaust pipe protector screw M6 4 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Exhaust pipe bracket bolt M8 1 20 Nm (2.0 m·kgf, 14 ft·lbf)
Frame and silencer bolt (front) M8 1 30 Nm (3.0 m·kgf, 22 ft·lbf)
Frame and silencer bolt (rear) M 8 1 30 Nm (3.0 m·kgf, 22 ft·lbf)
Exhaust pipe clamp bolt M8 2 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Silencer body bolt M5 6 8 Nm (0.8 m·kgf, 5.8 ft·lbf)
Oil nozzle bolt M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Engine oil drain bolt M10 1 20 Nm (2.0 m·kgf, 14 ft·lbf)
Crankcase bolt M6 12 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Clutch cable holder bolt M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Crankshaft end accessing screw M36 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Timing mark accessing screw M14 1 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Drive chain sprocket cover bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Crankcase bearing cover plate
screw M6 8 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Crankcase bearing cover plate
screw (crankshaft) M8 4 18 Nm (1.8 m·kgf, 13 ft·lbf) Crimp.
Clutch cover bolt M6 7 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil level check window bolt M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Left crankcase cover bolt M6 7 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Right crankcase cover bolt M6 11 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil filter element cover bolt M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil level check window bolt M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Kick shaft ratchet wheel guide bolt M6 2 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Kick starter lever bolt M8 1 33 Nm (3.3 m·kgf, 24 ft·lbf)
Kick starter lever boss screw M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Primary drive gear nut M20 1 100 Nm (10 m·kgf, 72 ft·lbf)
Clutch spring bolt M6 6 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Clutch boss nut M20 1 75 Nm (7.5 m·kgf, 54 ft·lbf)
ITEM
Thread
size Q’ty TIGHTENING TORQUES RemarksLT
LT
LT
LT
LT
LT
LT

CABLE ROUTING DIAGRAM
2-40
1. Main harness
2. Radiator3. Throttle position sensor lead
4. Joint coupler
5. Intake air temperature sensor lead6. Intake air pressure sensor lead
7. Frame
8. Fuel hose9. High tension cord
10. Spark plug cap
11. Cylinder head cover12. Sub-wire harness
13. Injector coupler
14. Injector lead15. Throttle body
16. Air filter case
17. ECU18. Sub-wire harness coupler
A. Fix the main harness by the plastic clamp, and in-sert the projection of the plastic clamp into the
hole in the sheet metal of the radiator.
B. Insert the projection of the main harness into the
hole in the frame.
C. To the sub-wire harness
D. Pass the high tension cord above the fuel hose.
E. ±10°F. Install the spark plug cap with this facing the right
of the vehicle.
G. Push the spark plug cap home, where there shall
be no gap between it and the cylinder head cover.
H. Pass the injector lead to the top of the vehicle be-yond the fuel hose.I. Insert the coupler of the sub-wire harness into the
rib of the air filter case.
J. Pass the sub-wire harness between the ECU and
the air filter case.

3
PERIODIC CHECKS AND ADJUSTMENTS
MAINTENANCE INTERVALS.......................................................................... 3-1
MAINTENANCE INTERVALS .................................................................... 3-1
PRE-OPERATION INSPECTION AND MAINTENANCE................................. 3-7
GENERAL INSPECTION AND MAINTENANCE........................................ 3-7
ENGINE............................................................................................................ 3-8
CHECKING THE COOLANT LEVEL .......................................................... 3-8
CHECKING THE COOLING SYSTEM ....................................................... 3-8
CHANGING THE COOLANT...................................................................... 3-8
CHECKING THE RADIATOR CAP ............................................................ 3-9
CHECKING THE RADIATOR CAP OPENING PRESSURE ...................... 3-9
CHECKING THE COOLANT CIRCULATORY SYSTEM FOR LEAKS .... 3-10
ADJUSTING THE CLUTCH LEVER POSITION ...................................... 3-10
ADJUSTING THE CLUTCH LEVER FREE PLAY .................................... 3-10
ADJUSTING THE THROTTLE GRIP FREE PLAY .................................. 3-11
LUBRICATING THE THROTTLE CABLE ................................................ 3-12
CLEANING THE AIR FILTER ELEMENT................................................. 3-12
CHECKING THE THROTTLE BODY JOINT ............................................ 3-13
CHECKING THE BREATHER HOSES .................................................... 3-13
CHECKING THE EXHAUST SYSTEM..................................................... 3-13
CHECKING THE FUEL LINE ................................................................... 3-14
CHECKING THE ENGINE OIL LEVEL..................................................... 3-14
CHANGING THE ENGINE OIL ................................................................ 3-15
ADJUSTING THE ENGINE IDLING SPEED ............................................ 3-16
ADJUSTING THE VALVE CLEARANCE ................................................. 3-17
CHASSIS........................................................................................................ 3-21
BLEEDING THE BRAKE SYSTEM .......................................................... 3-21
CHECKING THE BRAKE HOSE .............................................................. 3-22
ADJUSTING THE FRONT BRAKE .......................................................... 3-22
ADJUSTING THE REAR BRAKE ............................................................. 3-23
CHECKING THE FRONT BRAKE PADS ................................................. 3-23
CHECKING THE REAR BRAKE PADS ................................................... 3-25
CHECKING THE REAR BRAKE PAD INSULATOR ................................ 3-26
CHECKING THE BRAKE FLUID LEVEL.................................................. 3-26
ADJUSTING THE DRIVE CHAIN SLACK ................................................ 3-27
CHECKING THE FRONT FORK LEGS ................................................... 3-28
CHECKING THE FRONT FORK PROTECTOR GUIDE .......................... 3-28
CLEANING THE FRONT FORK OIL SEAL AND DUST SEAL ................ 3-28
AIR BLEEDING FROM FRONT FORK .................................................... 3-28
ADJUSTING THE FRONT FORK LEGS .................................................. 3-29
CHECKING THE SWINGARM OPERATION ........................................... 3-30
CHECKING THE REAR SUSPENSION ................................................... 3-30
ADJUSTING THE REAR SHOCK ABSORBER ASSEMBLY ................... 3-30
CHECKING THE TIRES ........................................................................... 3-32
CHECKING AND TIGHTENING THE SPOKES ....................................... 3-32
CHECKING THE WHEELS ...................................................................... 3-33