2016 YAMAHA YZ450F engine

CYLINDER HEAD
5-20
EASB111213
CYLINDER HEAD
Removing the cylinder head
Order Part name Q’ty Remarks
Refer to “INSTALLING THE CYLINDER
HEAD” on page 5-23.
Seat Refer 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 tank Refer to “FUEL TANK” on page 7-1.
Exhaust pipe and silencer Refer to “ENGINE REMOVAL” on page 5-1.
Radiator hose Disconnect.
Coolant temperature sensor coupler Disconnect.
Throttle body Refer to “THROTTLE BODY” on page 7-5.
Camshaft Refer to “CAMSHAFT” on page 5-12.
Upper engine bracket Refer to “ENGINE REMOVAL” on page 5-1.
1 Bolt (cylinder head) 2
2 Bolt (cylinder head) 4
3 Cylinder head 1
4 Cylinder head gasket 1
7 66
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
15 Nm (1.5 m kgf, 11 ft Ibf)T.R.
*
20 Nm (2.0 mkgf, 14 ftIbf)T.
R.
30 Nm (3.0 mkgf, 22 ftIbf)
*

CLUTCH
5-38
EASB111231
CLUTCH
Removing the clutch
Order Part name Q’ty Remarks
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
Brake pedal Refer to “ENGINE REMOVAL” on page 5-1.
1 Clutch cable 1 Disconnect.
2 Clutch cover 1
3 O-ring 1
4 Clutch spring 6
5 Pressure plate 1
6 Push rod 1 1
7 Circlip 1
8Washers 1
9 Bearing 1
10 Ball 1
11 Push rod 2 1
12 Friction plate 1 5
13 Clutch plate 7
LS
New
New
New
2
3 45
78961011
13
12
12
18
1
14
13
13
17
16
15
T.R.
T.R.
T.R.
T.R.
LT

CLUTCH
5-40
Removing the right crankcase cover
Order Part name Q’ty Remarks
Right engine guard Refer to “ENGINE REMOVAL” on page 5-1.
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
CoolantDrain.
Refer to “CHANGING THE COOLANT” on
page 3-8.
Brake pedal Refer to “ENGINE REMOVAL” on page 5-1.
Clutch cover Refer to “CLUTCH” on page 5-38.
1 Oil filter element cover 1
2 Oil filter element 1
3 Radiator pipe 2 1
4 Kickstarter lever 1
5 Right crankcase cover 1
6 Gaskets 1
7 Dowel pin 2
8Collar 1
For installation, reverse the removal proce-
dure.
T.R.
LS
New
New
67
2
5
4
1
7 8
New
3
LS
New
New
LS
LS
NewNew
LT
LS

CLUTCH
5-43
2. Check:
• Primary-drive-gear-to-primary-driven-gear
free play
Free play exists  Replace the primary
drive and primary driven gears as a set.
EASB111242CHECKING THE PRIMARY DRIVEN GEAR
1. Check:
• Primary driven gear
Damage/wear  Replace the primary drive
and primary driven gears as a set.
Excessive noise during operation  Re-
place the primary drive and primary driven
gears as a set.
EASB111243INSTALLING THE OIL SEAL
1. Install:
• Oil seal “1”
• Washer “2”
• Circlip “3”
TIP
• Apply is lithium-soap-based grease on the oil
seal lip.
• Install the oil seal in parallel with its manufac-
ture's marks or numbers facing inward.
EASB111244INSTALLING THE RIGHT CRANKCASE
COVER
1. Install:
• Dowel pin “1”
• O-rings “2”
• Collar “3”
• Gasket “4”
TIP
Apply the lithium-soap-based grease on the O-
ring.2. Install:
• Right crankcase cover “1”
• Right crankcase cover bolt “2”
TIP
• Apply the engine oil on the impeller shaft end.
• When installing the crankcase cover onto the
crankcase, make sure that the impeller shaft
end “3” aligns with the balancer end slot “4”.
• Tighten the right crankcase cover bolts in
stages and in a crisscross pattern.
New
New
3
2
1
LS
New
New
Right crankcase cover bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
1
1 4
2
New
New
3
LS
T R..
12

CLUTCH
5-44
EASB111245INSTALLING THE CLUTCH
1. Install:
• Push lever shaft “1”
TIP
• Apply the lithium-soap-based grease on the
oil seal lip.
• Before installation, apply the engine oil to the
push lever shaft sliding surface.
2. Install:
• Primary driven gear “1”
• Thrust washer “2”
• Clutch boss “3”
TIP
Apply the engine oil on the primary driven gear
inner circumference.
3. Install:
• Conical washer “1”
• Clutch boss nut “2”
ECA1DX1020
NOTICE
Make sure to tighten to specification; other-
wise, it may damage the other part that is
fastened together.
TIP
• Install the conical washer with its convex sur-
face “a” outward.
• Apply engine oil to the threads and contact
surface of the clutch boss nut.
• Apply engine oil to the contact surfaces of the
conical washer.
• Use the clutch holding tool “3” to hold the
clutch boss.
4. Install:
• Friction plates
• Clutch plate “2”
• Friction plate 2 “3”
TIP
• Install the clutch plates and friction plates al-
ternately on the clutch boss, starting with a
friction plate and ending with a friction plate.
• From the clutch boss side, install the friction
plates in order: friction plate 1  3, friction
plate 2 (identification color: purple)  3, and
friction plate 1  2.
• Apply the engine oil on the friction plates and
clutch plates. Clutch boss nut
75 Nm (7.5 m·kgf, 54 ft·lbf)
1
New
T R..
Clutch holder
90890-04086
YM-91042
a2
3
21

CLUTCH
5-45
5. Install:
• Bearing “1”
• Washer “2”
• Circlip “3”
To push rod 1 “4”.
TIP
Apply the engine oil on the bearing and washer.
6. Install:
• Push rod 2 “1”
•Ball “2”
• Push rod 1 “3”
TIP
Apply the engine oil on the push rod 1, 2 and
ball.7. Install:
• Pressure plate “1”
8. Install:
• Clutch spring
• Clutch spring bolt
TIP
Tighten the bolts in stages and in a crisscross
pattern.
9. Install:
• O-ring “1”
TIP
Apply the lithium-soap-based grease to the O-
ring.
a. Identification color
1
2a
3
2
2
1
New
Clutch spring bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
T R..
New

KICKSTATER
5-49
3. Install:
•Transmission
TIP
Slide the spring guide into the kick shaft, make
sure the groove “a” in the spring guide fits on
the stopper of the torsion spring.
4. Install:
• Kick shaft assembly “1”
TIP
• Before installation, apply molybdenum disul-
fide grease to the contacting surfaces of the
kick shaft ratchet wheel guide “2” and the kick
shaft stopper “a”.
• Apply the engine oil on the kick shaft.
• Slide the kick shaft assembly into the crank-
case and make sure the kick shaft stopper “a”
fits into the kick shaft ratchet wheel guide.5. Install:
• Torsion spring “1”
TIP
Turn the torsion spring clockwise and hook into
the proper hole “a” in the crankcase.
EASB111252INSTALLING THE KICK IDLE GEAR
1. Install:
• Kick idle gear “1”
• Washer “2”
• Circlip “3”
TIP
• Apply the engine oil on the kick idle gear inner
circumference.
• Install the kick idle gear with its depressed
side “a” toward you.
1 2a b
New

SHIFT SHAFT
5-53
EASB111259INSTALLING THE STOPPER LEVER
1. Install:
• Torsion spring “1”
• Collar “2”
• Stopper lever “3”
• Bolt (stopper lever) “4”
EASB111260INSTALLING THE SEGMENT
1. Install:
• Segment “1”
• Segment bolt
TIP
• Align the notch “a” on the segment with the
pin “b” on the shift cam.
• With the stopper lever pushed down, install
the segment.
ECA
NOTICE
If the segment gets an impact, the stopper
lever may be damaged. Take care not to
give an impact to it when tightening the bolt.
EASB111261INSTALLING THE SHIFT GUIDE AND SHIFT
LEVER ASSEMBLY
1. Install:
• Spring “1”
• Pawl pin “2”
•Pawl “3”
(to the shift lever “4”)
TIP
Apply the engine oil on the spring, pawl pin and
pawl.
2. Install:
• Shift lever assembly “1”
(to the shift guide “2”)
3. Install:
• Shift lever assembly “1”
• Shift guide “2”
TIP
• The shift lever assembly is installed at the
same time as the shift guide.
• Apply the engine oil on the segment bolt shaft. Bolt (stopper lever)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
LOCTITE®
Segment bolt
30 Nm (3.0 m·kgf, 22 ft·lbf)
T R..
2 1
3
4
LT
T R..1
2
1 2