2014 YAMAHA YZ450F engine

HANDLEBAR
4-31
EAS1SL1161
HANDLEBAR
Removing the handlber
OrderPart name Q’tyRemarks
Number plate Remove the band only.
1 Clutch cable 1 Disconnect.
2 Clutch lever holder 1
3 Engine stop switch 1
4 Brake master cylinder 1
5 Throttle cable cap 1
6 Throttle cable (pull) 1 Disconnect.
7 Throttle cable (return) 1 Disconnect.
8 Right grip 1
9 Tube guide 1
10 Collars 1
11 Left grip 1
12 Handlebar upper holder 2
13 Handlebar 1
14 Handlebar lower holder 2
15 Damper 4

HANDLEBAR
4-34
3. Tighten:
• Lower handlebar holder nut
4. Install:
• Handlebar grip “1”
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Slightly coat the handlebar left end with a
rubber adhesive.
b. Install the handlebar grip on the handlebar
by pressing the grip from the left side.
c. Wipe off any excess adhesive with a clean
cloth.
EWA13120
WARNING
Do not touch and move the handlebar grip
until its adhesive dries completely.
TIP
Install the handlebar grip to the handlebar so
that the line “a” between the two arrow marks
faces straight upward.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Install:
• Engine stop switch “1”
• Clutch lever “2”
• Clutch lever holder “3”
•Clamp “4”
TIP
• The engine stop switch, the clutch lever, and
the clutch lever holder should be installed ac
-
cording to the dimensions shown.
• Pass the engine stop switch lead through the
middle of the clutch lever holder.
Lower handlebar holder nut
40 Nm (4.0 m·kgf, 29 ft·lbf)
3
4
T R..
Engine stop switch screw
0.5 Nm (0.05 m·kgf, 0.36 ft·lbf)
Clutch lever holder bolt
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
T R..

CHAIN DRIVE
4-63
EAS1SL1189
CHAIN DRIVE
Removing the drive chain
Job OrderPart nameQ’tyServicing Information
Drive sprocketRefer to “ENGINE REMOVAL” on page 5-1.
1Drive chain1
For installation, reverse the removal proce-dure.
1
T.R.75 Nm (7.5 mlbf) kgf, 54 ft
T.R.7 Nm (0.7 mlbf) kgf, 5.1 ft

CHAIN DRIVE
4-65
4. Check:
• Drive chain rollers “1”
Damage/wear  Replace the drive chain.
• Drive chain side plates “2”
Damage/wear  Replace the drive chain.
5. Lubricate:
•Drive chain
EAS1SL1192CHECKING THE DRIVE SPROCKET
1. Check:
• Drive sprocket
More than 1/4 tooth wear “a”  Replace the
drive sprocket and the rear wheel sprocket
as a set.
Bent tooth  Replace the drive sprocket
and the rear wheel sprocket as a set.
EAS1SL1193CHECKING THE REAR WHEEL SPROCKET
Refer to “CHECKING AND REPLACING THE
REAR WHEEL SPROCKET” on page 4-8.
EAS1SL1194INSTALLING THE DRIVE CHAIN
1. Install:
• Drive chain “1”
• Drive chain joint “2”
• Joint clip “3” EWA
WARNING
When installing the joint clip, always keep
the direction as shown in the figure.
2. Lubricate:
•Drive chain
3. Install:
• Drive sprocket
• Lock washer
• Drive sprocket nut
Refer to “ENGINE REMOVAL” on page 5-1.
ECA1DX1014
NOTICE
Never install a new drive chain onto worn
drive sprockets; this will dramatically short
-
en the drive chain’s life.
4. Adjust:
• Drive chain slack
Refer to “ADJUSTING THE DRIVE CHAIN
SLACK” on page 3-27.
ECA13550
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci
-
fied limits.
b. Correct
1. Drive chain roller
2. Drive sprocket
New
Drive sprocket nut
75 Nm (7.5 m·kgf, 54 ft·lbf)
Drive chain slack
50–60 mm (1.97–2.36 in)
New
T R..

5
ENGINE
ENGINE REMOVAL......................................................................................... 5-1
REMOVING THE SILENCER ..................................................................... 5-6
REMOVING THE EXHAUST PIPE 2.......................................................... 5-6
REMOVING THE DRIVE SPROCKET ....................................................... 5-6
REMOVING THE ENGINE ......................................................................... 5-7
CHECKING THE SILENCER AND EXHAUST PIPE.................................. 5-7
CHANGING THE SILENCER FIBER ......................................................... 5-7
INSTALLING THE ENGINE........................................................................ 5-8
INSTALLING THE BRAKE PEDAL ............................................................ 5-9
INSTALLING THE DRIVE SPROCKET...................................................... 5-9
INSTALLING THE EXHAUST PIPE AND MUFFLER............................... 5-10
CAMSHAFT.................................................................................................... 5-11
REMOVING THE CAMSHAFT ................................................................. 5-13
CHECKING THE CAMSHAFT.................................................................. 5-14
CHECKING THE TIMING CHAIN AND CAMSHAFT SPROCKET .......... 5-15
CHECKING THE TIMING CHAIN TENSIONERS .................................... 5-15
CHECKING THE DECOMPRESSION SYSTEM...................................... 5-16
INSTALLING THE CAMSHAFTS ............................................................. 5-16
CYLINDER HEAD........................................................................................... 5-19
REMOVING THE CYLINDER HEAD........................................................ 5-21
CHECKING THE TIMING CHAIN GUIDE (INTAKE SIDE) ...................... 5-21
CHECKING THE CYLINDER HEAD ........................................................ 5-21
INSTALLING THE CYLINDER HEAD ...................................................... 5-22
VALVES AND VALVE SPRINGS................................................................... 5-24
REMOVING THE VALVES ....................................................................... 5-25
CHECKING THE VALVES AND VALVE GUIDES ................................... 5-26
CHECKING THE VALVE SEATS ............................................................. 5-27
CHECKING THE VALVE SPRINGS......................................................... 5-29
CHECKING THE VALVE LIFTERS .......................................................... 5-29
INSTALLING THE VALVES ..................................................................... 5-30
CYLINDER AND PISTON............................................................................... 5-32
REMOVING THE PISTON ....................................................................... 5-33
CHECKING THE CYLINDER AND PISTON ............................................ 5-33
CHECKING THE PISTON RINGS............................................................ 5-34
CHECKING THE PISTON PIN ................................................................. 5-35
INSTALLING THE PISTON AND CYLINDER .......................................... 5-35

ENGINE REMOVAL
5-1
EAS1SL1195
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.
EAS1SL1196
ENGINE REMOVAL
Removing the exhaust pipe
OrderPart nameQ’tyRemarks
Side cover (right)Refer to “GENERAL CHASSIS” on page 4-1.
Rear shock absorber assembly lower boltRefer to “REAR SHOCK ABSORBER AS-SEMBLY” on page 4-53.
Connecting arm bolt (frame side)Refer to “REAR SHOCK ABSORBER AS-SEMBLY” on page 4-53.
1Silencer clamp1Loosen.
2Silencer1
3Exhaust pipe 2 clamp1Loosen.
4Exhaust pipe 21
5Exhaust pipe 11
6Gaskets3
10
5
9
2 6
1
66
3
84 7 (8)
(6)
30 Nm (3.0 mkgf, 22 ftIbf)T.R.
30 Nm (3.0 mkgf, 22 ftIbf)T.R.
8 Nm (0.8 mkgf, 5.8 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
New
New
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
12 Nm (1.2 mkgf, 8.7 ftIbf)T.R.12 Nm (1.2 mkgf, 8.7 ftIbf)T.R.
20 Nm (2.0 mkgf, 14 ftIbf)T.R.
New
1st 7 Nm (0.7 mkgf, 5.1 ftlbf)
2nd 10 Nm (1.0 m
kgf, 7.2 ftlbf)T.
R
.
LT
LT
LT

ENGINE REMOVAL
5-2
7Exhaust pipe 1 protector1
8Exhaust pipe 2 protector1
9Silencer body1
10Silencer cap1
For installation, reverse the removal proce-dure.
Removing the exhaust pipe
Order Part name Q’ty Remarks
10
5
9
2 6
1
66
3
84 7 (8)
(6)
30 Nm (3.0 mkgf, 22 ftIbf)T.R.
30 Nm (3.0 mkgf, 22 ftIbf)T.
R
.
8 Nm (0.8 mkgf, 5.8 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
New
New
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
12 Nm (1.2 mkgf, 8.7 ftIbf)T.R.12 Nm (1.2 mkgf, 8.7 ftIbf)T.R.
20 Nm (2.0 mkgf, 14 ftIbf)T.R.
New
1st 7 Nm (0.7 mkgf, 5.1 ftlbf)
2nd 10 Nm (1.0 m
kgf, 7.2 ftlbf)T.
R
.
LT
LT
LT

ENGINE REMOVAL
5-3
Removing the electronic parts
OrderPart nameQ’tyRemarks
Use a suitable stand to raise the front wheel
off the ground.
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 case cover
1Rectifier/regulator1
2ECU1
3Ignition coil1
4Condenser1
5Neutral switch1
6AC magneto lead1Disconnect.
7Crankshaft position sensor coupler1Disconnect.
8Coolant temperature sensor coupler1Disconnect.
For installation, reverse the removal proce-dure.
T.R.
T.R.
T.R.T.R.
8 3
7
6
154
2
LT