2014 YAMAHA YZ450F brake

EAS1SL1007
SYMBOLS
The following symbols are used in this manual for easier understanding.
TIP
The following symbols are not relevant to every vehicle.
SYMBOLDEFINITIONSYMBOLDEFINITION
Serviceable with engine mountedGear oil
Filling fluidMolybdenum disulfide oil
LubricantBrake fluid
Special toolWheel bearing grease
Tightening torqueLithium-soap-based grease
Wear limit, clearanceMolybdenum disulfide grease
Engine speedSilicone grease
Electrical dataLocking agent (LOCTITE®)
Engine oilReplace the part with a new one.
G
M
BF
B
T R..
LS
M
S
LT
E
New

1
GENERAL INFORMATION
LOCATION OF IMPORTANT LABELS............................................................ 1-1
DESCRIPTION .................................................................................................. 1-4
IDENTIFICATION ............................................................................................. 1-5
VEHICLE IDENTIFICATION NUMBER ...................................................... 1-5
ENGINE SERIAL NUMBER ....................................................................... 1-5
MODEL LABEL........................................................................................... 1-5
FEATURES ....................................................................................................... 1-6
OUTLINE OF THE FI SYST EM .................................................................. 1-6
FI SYSTEM....................................... .......................................................... 1-7
INCLUDED PARTS .......................................................................................... 1-8
SIDESTAND ............................................................................................... 1-8
SPARK PLUG WRENCH ........................................................................... 1-8
NIPPLE WRENCH...................................................................................... 1-8
HANDLEBAR PROTECTOR .. .................................................................... 1-8
FUEL HOSE JOINT COVER ...................................................................... 1-8
COUPLER FOR CONNECTING OPTIONAL PART................................... 1-8
IMPORTANT INFORMATION ........................................................................ 1-10
PREPARATION FOR REMOVAL A ND DISASSEMBLY.......................... 1-10
REPLACEMENT PARTS.......................................................................... 1-10
GASKETS, OIL SEALS AND O-RINGS ................................................... 1-11
LOCK WASHERS/PLATES AND COTTER PINS .................................... 1-11
BEARINGS AND OIL SEALS ................................................................... 1-11
CIRCLIPS ................................................................................................. 1-11
BASIC SERVICE INFORMATION .................................................................. 1-12
ELECTRICAL SYSTEM.......... .................................................................. 1-12
SPECIAL TOOLS ........................................................................................... 1-15
CONTROL FUNCTIONS ................................................................................ 1-20
ENGINE STOP SWITCH .......................................................................... 1-20
CLUTCH LEVER ................................................................................... ... 1-20
SHIFT PEDAL .......................................................................................... 1-20
KICKSTARTER LEVER.......... .................................................................. 1-20
THROTTLE GRIP ..................................................................................... 1-20
FRONT BRAKE LEVER ........................................................................... 1-20
REAR BRAKE PEDAL.............................................................................. 1-21
STARTER KNOB/IDLE SCREW .............................................................. 1-21
FUEL TANK CAP ..................................................................................... 1-21

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

CONTROL FUNCTIONS
1-20
EAS1SL1032
CONTROL FUNCTIONS
EAS1SL1033ENGINE STOP SWITCH
The engine stop switch “1” is located on the left
handlebar. Continue pushing the engine stop
switch till the engine comes to a stop.
EAS1SL1034CLUTCH LEVER
The clutch lever “1” is located on the left han-
dlebar. The clutch lever disengages or engag-
es the clutch.
Pull the clutch lever toward the handlebar to
disengage the clutch, and release the lever to
engage the clutch.
EAS1SL1035SHIFT PEDAL
The shift pedal “1” has adopted a method of 1
down & 4 ups (press-down & kick-ups).
Press it down for N (neutral) to 1st, and kick it
up for 2nd to 5th.
EAS1SL1036
KICKSTARTER LEVER
The kickstarter lever “1” is in the right of the
chassis.
To start the engine, pull out and push down the
kickstarter lever with your foot.
EAS1SL1037THROTTLE GRIP
The throttle grip “1” is located on the right han-
dlebar. The throttle grip accelerates or deceler-
ates the engine. For acceleration, turn the grip
toward you; for deceleration, turn it away from
you.
EAS1SL1038FRONT BRAKE LEVER
The front brake lever “1” is located on the right
handlebar. Pull it toward the handlebar to acti
-
vate the front brake.
EAS1SL1039
1
1

CONTROL FUNCTIONS
1-21
REAR BRAKE PEDAL
The rear brake pedal “1” is in the right of the
chassis. Press down on the brake pedal to ac-
tivate the rear brake.
EAS1SL1040STARTER KNOB/IDLE SCREW
Starting a cold engine requires a larger amount
of intake air, which is supplied by the starter
knob/idle screw “1.”
Pulling the knob toward “a” turns ON the start-
er, resulting in a larger amount of intake air.
Pushing the knob toward “b” turns OFF the
starter.
EWA@
WARNING
While handling the starter knob/idle screw,
take care not to burn yourself on exhaust
pipes.
EAS1SL1040FUEL TANK CAP
Fuel tank cap “1” is located under the fuel tank
cap cover “2”.
Remove the fuel tank cap cover to open the fuel
tank cap.
TIP
• To remove the fuel tank cap cover, insert fin-gers under part “a”, and then use both hands
to lift it up towards the rear of the vehicle.
• Install the fuel tank cap cover after placing the
bands “3” all the way in under the seat.
1
a b1
1
23
a
2

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

MAINTENANCE AFTER BREAK-IN
1-24
MAINTENANCE AFTER BREAK-IN
After a break-in, perform careful maintenance
to get ready for the next practice or race.
Refer to “PRE-OPERATION INSPECTION
AND MAINTENANCE” on page 3-7.
EAS1SL1047MAJOR MAINTENANCE
1. For the engine
• Leaks around the engine
Check for pressure leaks from the cylinder
head or the cylinder, oil leaks from the
crankcase or the case cover, leaks from the
coolant system, and other leaks.
• Check that the valve, the cylinder head, the
cylinder, the piston, and the piston ring fit
one another, and that contact between the
valve and the cylinder head, and that be
-
tween the cylinder and the piston are cor-
rect.
• Engine oil change
Drain the oil, and check for dirt and foreign
materials such as metal chips. (If any foreign
material is mixed, disassemble and check
the crankcase.)
Pour the specified amount of the recom-
mended oil.
• AC magneto
Check for looseness in mounted areas of
the rotor and the stator.
Check that the connector is not being dis-
connected.
• Silencer
Check the main body and stay for cracks.
Check for leaks.
• Mounting bolts and nuts
Check for looseness in mounted areas of
parts, as well as engine mounting bolts and
engine brackets.
2. For the chassis
• Check welds and mounted areas of the
frame, the swingarm, the link, the bracket,
and so on, for looseness and cracks.
• Wheel (s)
Check the wheel for runout. Check the
spoke for looseness.
• Brake(s)
Check the brake disc mounting bolt for
looseness.
Check that the reservoir contains the speci-
fied amount of brake fluid. Check for leaks.
• Cable
Grease and adjust cables.
•Drive chain
Lubricate the drive chain and adjust its ten-
sion.
• Fuel tank
Clean the inside of the fuel tank. Check for
leaks.
• Suspension
Check for oil leaks in the front fork or the rear
shock absorber. Check that the mounted
conditions are good.
• Sprocket
Check for looseness in the sprocket mount-
ed on the rear wheel.
• Mounting bolts and nuts
Check mounted areas for looseness.JCA1SL1001
NOTICE
After a break-in or before each race, always
check the points shown in “TORQUE-
CHECK POINTS” for tightening torques and
retighten them. (Refer to
“TORQUE-CHECK
POINTS”.)
• Greasing and oiling
Always grease or oil the specified points.

TORQUE-CHECK POINTS
1-25
EAS1SL1048
TORQUE-CHECK POINTS
Frame constructionFrame to rear frame
Frame to engine protector
Combined seat and fuel tankFuel tank to frame
Engine mountingFrame to engine
Engine bracket to engine
Engine bracket to frame
SeatSeat to frame
SteeringSteering stem to handlebarSteering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
SuspensionFrontSteering stem to front forkFront fork to upper bracket
Front fork to lower bracket
RearLinkAssembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Mounting of rear shock absorberRear shock absorber and frame
Mounting of swingarmTightening of pivot shaft
Wheel (s)Mounting of wheelFrontTightening of wheel axle
Tightening of axle holder
Tightening of spoke nipple
RearTightening of wheel axle
Wheel to rear wheel sprocket
Tightening of spoke nipple
Brake(s)FrontBrake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handle-
bar
Tightening of bleed screw
Tightening of brake hose holder
RearBrake pedal to frame
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Tightening of brake hose holder
Fuel systemFuel pump to fuel tank