2014 YAMAHA YZ450F engine

TRANSMISSION
5-73
2. Install:
• Collar “1”
• 2nd wheel gear (23T) “2”
• 4th wheel gear (24T) “3”
• 3rd wheel gear (26T) “4”
• 5th wheel gear (20T) “5”
• Collar “6”
• 1st wheel gear (27T) “7”
• O-rings “8”
(to the drive axle “9”)
TIP
• Before installation, apply molybdenum disul-
fide oil to the inner and end surface of the idler
gear and to the inner surface of the sliding
gear, then install.
• Apply the lithium-soap-based grease on the
O-ring.
3. Install:
• Washer “1”
• Circlip “2”
TIP
• Be sure the circlip sharp-edged corner “a” is
positioned opposite side to the washer and
gear “b”.
• Install the circlip with its ends “c” settled even-
ly on the spline crests.
4. Install:
• Collar “1”
TIP
• Apply the lithium soap base grease on the oil
seal lip.
• When installing the collar into the crankcase,
pay careful attention to the crankcase oil seal
lip.
5. Install:
• Main axle “1”
• Drive axle “2”
TIP
• Install to the left crankcase simultaneously.
• Apply engine oil to the main axle and the drive
axle bearing.
New
298
3
4
5
6
7
New
M
LS
1
New
21
2
ab
cc
1
2
EE

TRANSMISSION
5-74
6. Install:
• Shift fork 1 (L) “1”
• Shift fork 2 (C) “2”
• Shift fork 3 (R) “3”
• Shift cam “4”
(to the main axle and the drive axle)
TIP
• Apply molybdenum disulfide oil to the shift
fork grooves.
• Apply engine oil to the shift cam groove and
the bearing contact surface.
• Mesh the shift fork 1 (L) with the 4th wheel
gear “5” and 3 (R) with the 5th wheel gear “7”
on the drive axle.
• Mesh the shift fork 2 (C) with the 3rd pinion
gear “6” on the main axle.
7. Install:
• Long shift fork guide bar “1”
• Short shift fork guide bar “2”
• Spring “3”
TIP
• Screw the spring into the shift fork guide bar
lightly beforehand.
• Apply the engine oil on the shift fork guide
bars.
8. Check:
• Operation of shift cam and shift fork
• Transmission operation
Unsmooth operation  Repair.
3
12
2 13
E

RADIATOR
6-1
EAS1SL1294
TIP
This section is intended for those who have basic knowledge and skill concerning the servicing of
Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.). Those who have little knowl
-
edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas-
sembly, or reassembly only by reference to this manual. It may lead to servicing trouble and
mechanical damage.
EAS1SL1295
RADIATOR
Removing the radiator
OrderPart nameQ’tyRemarks
CoolantDrain.Refer to “CHANGING THE COOLANT” on page 3-8.
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.
Air filter caseRefer to “THROTTLE BODY” on page 7-5.
1Radiator guard2
2Radiator hose clamp8Loosen.
3Right radiator1
11
12
New
New
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LS
LS

WATER PUMP
6-4
EAS1SL1298
WATER PUMP
Removing the water pump
OrderPart nameQ’tyRemarks
CoolantDrain.Refer to “CHANGING THE COOLANT” on page 3-8.
Engine oilDrain.Refer to “CHANGING THE ENGINE OIL” on page 3-15.
Right crankcase coverRefer to “CLUTCH” on page 5-37.
1Water pump housing1
2Dowel pin2
3Gasket1
4Collar1
5Pin1
6Impeller shaft assembly1
7Oil seal1
8Bearing1
9Oil seal1
For installation, reverse the removal proce-dure.
7
6
2
2
3
1
854
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
New
New
New
E
9
New
E

WATER PUMP
6-5
EAS1SL1299REMOVING THE OIL SEAL
TIP
• Remove the oil seal when the coolant level
changes frequently more than usual, coolant
has discolored, or engine oil has become
milky.
• Do not use the removed oil seal.
1. Remove:
• Oil seals “1”
EAS1SL1300CHECKING THE WATER PUMP
1. Check:
• Water pump housing cover
• Impeller shaft
Cracks/damage/wear  Replace.
EAS1SL1301CHECKING THE BEARING
1. Check:
• Bearing
Rotate the inner race with your finger.
Rough spot/seizure  Replace.
EAS1SL1302INSTALLING THE OIL SEAL
1. Install:
• Oil seals “1”
TIP
• Apply the lithium soap base grease on the oil
seal lip.
• Install the oil seal with its manufacture's
marks or numbers facing the right crankcase
cover “2”.
2. Install:
• Bearing “1”
TIP
Install the bearing by pressing its outer race
parallel.
EAS1SL1303ASSEMBLING THE WATER PUMP
1. Install:
• Impeller shaft assembly “1”
•Pin “2”
• Collar “3”
• Circlip “4”
TIP
• Take care so that the oil seal lip is not dam-
aged or the spring does not slip off its posi-
tion.
• When installing the impeller shaft, apply the
engine oil to the oil seal lip, the bearing, and
the impeller shaft.
1 1
New
1 1New
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LS
LS
New
4
1
23New
E

FUEL TANK
7-1
EAS1SL1304
TIP
This section is intended for those who have basic knowledge and skill concerning the servicing of
Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.). Those who have little knowl
-
edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas-
sembly, or reassembly only by reference to this manual. It may lead to servicing trouble and
mechanical damage.
EAS1SL1305
FUEL TANK
Removing the fuel tank
OrderPart nameQ’tyRemarks
SeatRefer to “GENERAL CHASSIS” on page 4-1.
Side cover (left/right)
Air scoop (left/right)
1Fuel pump coupler1Disconnect.
2Fuel hose1Disconnect.
3Fuel tank1
4Fuel pump bracket1
5Fuel pump1
6Fuel pump gasket1
For installation, reverse the removal proce-dure.
4(6) (2)
(2) (2)(2)2
5
6
3
1
New
4.0 Nm (0.40 mkgf, 2.9 ftIbf)T.R.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.
R
.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
9 Nm (0.9 mkgf, 6.5 ftIbf)T.
R
.
4.0 Nm (0.40 mkgf, 2.9 ftIbf)T.R.

FUEL TANK
7-4
e. Start the engine.
f. Measure the fuel pressure.
Out of specification  Replace the fuel
pump.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1312CHECKING THE DAMPER
1. Check:
• Damper 1 “1”
• Damper 2 “2”
• Damper 3 “3”
Wear/damage  Replace.
TIP
• Affix dampers 1 and 3 with the arrow on each
damper pointing outward.
• Affix the damper 2 with its projection “a” facing
the rear of the vehicle.
EAS1SL1313
CHECKING AND REPLACING THE PRO-
TECTOR
1. Check:
• Protector “1”
Wear/damage  Replace.
TIP
Affix the protector as shown.
Fuel pressure
324.0 kPa (3.24 kgf/cm2, 47.0
psi)
1
2
84 mm
(3.31 in)115 mm
(4.53 in)
84 mm
(3.31 in)115 mm
(4.53 in)
3 1
13a
2
A. Left
B. Right
1
1
0 mm
(0 in)
A
B
1
15 mm
(0.59 in)
1

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.