2012 YAMAHA YZ450F diagram

HOW TO READ DESCRIPTIONS
To help identify parts and clarify pro-
cedure steps, there are exploded dia-
grams at the start of each removal
and disassembly section.
1. An easy-to-see exploded diagram
"1" is provided for removal and
disassembly jobs.2. Numbers "2" are given in the or-
der of the jobs in the exploded di-
agram. A number that is enclosed
by a circle indicates a disassem-
bly step.
3. An explanation of jobs and notes
is presented in an easy-to-read
way by the use of symbol marks
"3". The meanings of the symbol
marks are given on the next page.4. A job instruction chart "4" accom-
panies the exploded diagram,
providing the order of jobs, names
of parts, notes in jobs, etc.
5. For jobs requiring more informa-
tion, the step-by-step format sup-
plements "5" are given in addition
to the exploded diagram and job
instruction chart.
ILLUSTRATED SYMBOLS (Refer to
the illustration)Illustrated symbols "1" to "7" are used
to identify the specifications appear-
ing in the text.
1. With engine mounted
2. Filling fluid
3. Lubricant
4. Special tool
5. Tightening
6. Specified value, Service limit
7. Resistance (Ω), Voltage (V),
Electric current (A)
Illustrated symbols "8" to "13" in the
exploded diagrams indicate grade of
lubricant and location of lubrication
point.
8. Apply engine oil
9. Apply molybdenum disulfide oil
10. Apply brake fluid
11. Apply lightweight lithium-soap
base grease
12. Apply molybdenum disulfide
grease13. Apply silicone grease
Illustrated symbols "14" to "15" in the
exploded diagrams indicate where to
apply a locking agent and where to in-
stall new parts.
14. Apply locking agent (LOC-
TITE
®)
15. Use new one
1
23
45

CONTENTS
CHAPTER 1
GENERAL INFOR-
MATION
LOCATION OF
IMPORTANT LABELS ..... 1-1
DESCRIPTION ................. 1-5
CONSUMER
INFORMATION................. 1-6
FEATURES....................... 1-7
INCLUDED PARTS .......... 1-9
IMPORTANT
INFORMATION................. 1-9
HANDLING THE
ELECTRONIC PARTS ... 1-10
CHECKING OF
CONNECTION ................ 1-10
SPECIAL TOOLS ........... 1-12
CONTROL
FUNCTIONS ................... 1-17
STARTING
AND BREAK-IN.............. 1-17
TORQUE-CHECK
POINTS........................... 1-19
CLEANING
AND STORAGE ............. 1-20
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-3
TIGHTENING
TORQUES ...................... 2-11
LUBRICATION
DIAGRAMS .................... 2-17
CABLE ROUTING
DIAGRAM ....................... 2-18
CHAPTER 3
REGULAR INSPEC-
TION AND AD-
JUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION
AND MAINTENANCE ....... 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-14
ELECTRICAL ................. 3-24
CHAPTER 4
ENGINE
SEAT
AND SIDE COVERS ......... 4-1
EXHAUST PIPE
AND SILENCER ............... 4-3
RADIATOR ....................... 4-5
CAMSHAFTS.................... 4-8
CYLINDER HEAD........... 4-13
VALVES AND
VALVE SPRINGS ........... 4-17
CYLINDER
AND PISTON .................. 4-21
CLUTCH ......................... 4-25
OIL FILTER ELEMENT
AND WATER PUMP ....... 4-29
BALANCER .................... 4-33
OIL PUMP ....................... 4-35
KICK SHAFT
AND SHIFT SHAFT ........ 4-38
AC MAGNETO................ 4-43
ENGINE REMOVAL ....... 4-45
CRANKCASE
AND CRANKSHAFT ...... 4-50
TRANSMISSION,
SHIFT CAM
AND SHIFT FORK .......... 4-56
CHAPTER 5
CHASSIS
FRONT WHEEL
AND REAR WHEEL .........5-1
FRONT BRAKE
AND REAR BRAKE..........5-6
FRONT FORK .................5-16
HANDLEBAR..................5-24
STEERING ......................5-28
SWINGARM ....................5-32
REAR
SHOCK ABSORBER ......5-37
CHAPTER 6
FUEL SYSTEM
FUEL TANK ......................6-1
THROTTLE BODY ............6-4
CHAPTER 7
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........7-1
IGNITION SYSTEM...........7-3
THROTTLE POSITION
SENSOR SYSTEM ...........7-6
FUEL INJECTION
SYSTEM............................7-9
FUEL PUMP SYSTEM ....7-35
ELECTRICAL
COMPONENTS...............7-36
CHAPTER 8
TUNING
CHASSIS ..........................8-1

2-17
LUBRICATION DIAGRAMS
LUBRICATION DIAGRAMS
1. Oil strainer
2. Oil check bolt
3. Scavenging pump
4. Oil feed pump
5. Oil filter element
6. Crankshaft
7. Oil nozzle
8. Exhaust camshaft
9. Intake camshaft10. Main axle
11. Drive axle
12. Oil level check window
13. Oil tank

2-18
CABLE ROUTING DIAGRAM
CABLE ROUTING DIAGRAM

2-19
CABLE ROUTING DIAGRAM
1. Fuel tank breather hose
2. Coupler for connecting optional
part
3. Cylinder head breather hose
4. Hose holder
5. Radiator hose 3A. Insert the end of the fuel tank
breather hose into the hole in
the steering stem.
B. Fit the accessory coupler into
the connector to fasten it to the
bracket.
C. Point the end of the cylinder
head breather hose downward.
D. Pass the cylinder head breather
hose through the hose holder,
making sure that the stopper on
the hose contacts the holder.
E. Route the cylinder head breath-
er hose between the frame and
radiator hose 3, and to the out-
side of the AC magneto lead.

2-20
CABLE ROUTING DIAGRAM
F-F
A
B
D-D
C-C
E
F
F
CC
DD
B
A
E
100mm

2-21
CABLE ROUTING DIAGRAM
1. Clutch cable
2. Throttle cable (return)
3. Throttle cable (pull)
4. Cable holder
5. Clamp
6. Rectifier/regulator
7. Ignition coil
8. Ignition coil coupler
9. AC magneto coupler
10. Radiator hose 2
11. Ground lead terminal
12. Plug cap
13. Ignition coil bracket
14. Clamp (lock)
15. Clamp (clip)
16. AC magneto lead
17. ECU bracket
18. Cylinder head cover installing
boltA. Pass the clutch cable, throttle
cables, and engine stop switch
lead through the cable holder.
Pass the clutch cable through
the lower guide only.
B. Route the engine stop switch
lead to the inside of the clip.
C. Fasten the rectifier/regulator
lead and engine stop switch lead
(wire harness end).
D. Insert the projection on the en-
gine stop switch coupler into the
hole in the bracket.
E. Insert the projection on the recti-
fier/regulator coupler into the
hole in the bracket.
F. Position the ignition coil bracket
to the outside of the ignition coil,
and insert the bolts from the igni-
tion coil side.
G. Fasten the AC magneto lead to
the ignition coil bracket with a
plastic locking tie, making sure
to position the tie above the low-
er mounting portion of the brack-
et. Face the buckle of the plastic
locking tie forward, and then cut
off the excess end of the tie.
H. Route the ignition coil lead be-
tween the condenser and the ig-
nition coil.
I. Fit the clip portion of the clamp
into the ignition coil bracket and
fasten the clutch cable with the
locking portion of the clamp.
J. Route the clutch cable to the
outside of the AC magneto lead.
K. Route the throttle cables under
radiator hose 2, making sure not
to twist the cables.
L. Route the AC magneto lead to
the inside of the throttle cables
and clutch cable.
M. Install the ground lead terminal
between the ECU bracket and
the cable holder, making sure to
position the terminal between
the stoppers.
N. Push in the spark plug cap com-
pletely, making sure that there is
no gap between the cylinder
head cover and the cap.
O. Pass the high tension cord so
that it may not go right over the
cylinder head cover installing
bolt when viewed directly from
above.
P. Apply sealant to the slit and in-
ner surface of the grommet, and
then install the grommet at the
position shown.

2-22
CABLE ROUTING DIAGRAM
B
B
FG
A-A
C-C
D-D
E-E
B-B
G
F
C
C
D
D
E
E
A
A