engine YAMAHA YZ450F 2016 Workshop Manual

ENGINE
3-21
EXHAUST
Example:
Valve clearance (cold) 0.18–0.25 mm
(0.0071–0.0098 in)
Installed is 175
Measured clearance 0.32 mm (0.0126 in)
Replace 175 pad with 185 pad
Pad No.175 = 1.75 mm (0.0689 in)
Pad No.185 = 1.85 mm (0.0728 in)
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 0.02 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220
0.03 0.07 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.08 0.12 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.13 0.17 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235
0.18 0.25
0.26 0.30 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.31 0.35 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.36 0.40 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.41 0.45 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.46 0.50 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.51 0.55 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.56 0.60 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.61 0.65 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.66 0.70 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.71 0.75 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.76 0.80 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.81 0.85 180 185 190 195 200 205 210 215 220 225 230 235 240
0.86 0.90 185 190 195 200 205 210 215 220 225 230 235 240
0.91 0.95 190 195 200 205 210 215 220 225 230 235 240
0.96 1.00 195 200 205 210 215 220 225 230 235 240
1.01 1.05 200 205 210 215 220 225 230 235 240
1.06 1.10 205 210 215 220 225 230 235 240
1.11 1.15 210 215 220 225 230 235 240
1.16 1.20 215 220 225 230 235 240
1.21 1.25 220 225 230 235 240
1.26 1.30 225 230 235 240
1.31 1.35 230 235 240
1.36 1.40 235 240
1.41 1.45 240
A. Measured clearance
B. Installed pad number
C. Standard clearance

CHASSIS
3-28
2. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
EWA
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor
lock.
ECA
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
EASB111097ADJUSTING THE DRIVE CHAIN SLACKECA13550
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.1. Use a suitable stand to raise the rear wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Shift the transmission into the neutral posi-
tion.
3. Pull the drive chain up above the drive chain
guide installation bolt with a force of about
50 N (5.0 kgf, 36 lbf).
4. Check:
• Drive chain slack “a”
Out of specification  Regulate.
TIP
Measure drive chain slack between the drive
chain guide and the bottom of the chain as
shown.
5. Adjust:
• Drive chain slack
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the wheel axle nut “1”.
b. Loosen both locknuts “2”.
c. Turn the adjusting bolt “3” in direction “a” or
“b” until the specified drive chain slack is ob-
tained. Specified brake fluid
DOT 4
A. Front brake
B. Rear brake
Drive chain slack
50–60 mm (1.97–2.36 in)
Direction “a”
The drive chain slack decreases.
Direction “b”
The drive chain slack increases.
a

ELECTRICAL SYSTEM
3-38
2. Attach:
• Timing light “1”
• Digital tachometer “2”
To the high tension code “3”.
3. Adjust:
• Engine idling speed
Refer to “ADJUSTING THE ENGINE
IDLING SPEED” on page 3-16.
4. Check:
• Ignition timing
Check whether the alignment mark “a” on
the left crankcase cover is within the firing
range “b” on the rotor.
Incorrect firing range  Check rotor and
Crankshaft position sensor.
5. Install:
• Timing mark accessing screwTiming light
90890-03141
YU-03141
Digital tachometer
90890-06760
YU-39951-B
Timing mark accessing screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1
3
a
b
T R..

GENERAL CHASSIS
4-1
EASB111116
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.
EASB111117
GENERAL CHASSIS
Removing the seat and side cover
Order Part name Q’ty Remarks
1 Seat 1
2 Air scoop (left) 1
3 Air scoop (right) 1
4 Side cover (left) 1
5 Side cover (right) 1
6 Number plate 1
7 Rear fender 1
For installation, reverse the removal proce-
dure.
4 (2)
75
1
3
6
2
7 Nm (0.7 m•kgf, 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.
7 Nm (0.7 mkgf, 5.1 ftIbf)T.R.
22 Nm (2.2 mkgf, 16 ftIbf)T.R.
1.3 Nm (0.13 mkgf, 0.94 ftIbf)T.R.16 Nm (1.6 mkgf, 12 ftIbf)T.R.

HANDLEBAR
4-32
EASB111160
HANDLEBAR
Removing the handlebar
Order Part name Q’ty Remarks
Number plate Remove the band only.
1 Clutch cable 1 Disconnect.
2 Clutch lever holder 1
3 Engine stop switch 1
4 Launch control switch 1
5 Brake master cylinder 1
6 Throttle cable cap 1
7 Throttle cable (pull) 1 Disconnect.
8 Throttle cable (return) 1 Disconnect.
9 Right grip 1
10 Tube guide 1
11 Collars 1
12 Left grip 1
13 Handlebar upper holder 2

HANDLEBAR
4-35
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
Securely support the vehicle so that there is
no danger of it falling over.
TIP
Install the handlebar grip to the handlebar so
that the line “a” between the two arrow marks
faces straight upward.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Install:
• Handlebar grip “1”
• Handlebar grip “2”
• Handlebar grip “3”
• Launch control switch “4”
•Clamp “5”
TIP
• The engine stop switch, the clutch lever, the
clutch lever holder and the launch control
switch should be installed according to the di-
mensions shown.
• Pass the engine stop switch lead through the
middle of the clutch lever holder.
6. Install:
• Right grip “1”
• Collar “2”
Apply adhesive to the tube guide “3”.
TIP
• Before applying the adhesive, wipe off grease
or oil on the tube guide surface “a” with a lac-
quer thinner.
• Install the grip to the tube guide so that the
grip match mark “b” and tube guide slot “c”
form the angle as shown. Lower handlebar holder nut
40 Nm (4.0 m·kgf, 29 ft·lbf)
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)
Launch control switch screw
1.3 Nm (0.13 m·kgf, 0.94 ft·lbf)
T R..

CHAIN DRIVE
4-65
EASB111188
CHAIN DRIVE
Removing the drive chain
Job Order Part name Q’ty Servicing Information
Drive sprocket Refer to “ENGINE REMOVAL” on page 5-1.
1 Drive chain 1
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
4-67
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
EASB111191CHECKING 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.
EASB111192CHECKING THE REAR WHEEL SPROCKET
Refer to “CHECKING AND REPLACING THE
REAR WHEEL SPROCKET” on page 4-8.
EASB111193
INSTALLING 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 3-28.
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
Drive sprocket nut
75 Nm (7.5 m·kgf, 54 ft·lbf)
Drive chain slack
50–60 mm (1.97–2.36 in)
New
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.................................................................................................... 5-12
REMOVING THE CAMSHAFT ................................................................. 5-14
CHECKING THE CAMSHAFT.................................................................. 5-15
CHECKING THE TIMING CHAIN AND CAMSHAFT SPROCKET .......... 5-16
CHECKING THE TIMING CHAIN TENSIONERS .................................... 5-16
CHECKING THE DECOMPRESSION SYSTEM...................................... 5-17
INSTALLING THE CAMSHAFTS ............................................................. 5-17
CYLINDER HEAD........................................................................................... 5-20
REMOVING THE CYLINDER HEAD........................................................ 5-22
CHECKING THE TIMING CHAIN GUIDE (INTAKE SIDE) ...................... 5-22
CHECKING THE CYLINDER HEAD ........................................................ 5-22
INSTALLING THE CYLINDER HEAD ...................................................... 5-23
VALVES AND VALVE SPRINGS................................................................... 5-25
REMOVING THE VALVES ....................................................................... 5-26
CHECKING THE VALVES AND VALVE GUIDES ................................... 5-27
CHECKING THE VALVE SEATS ............................................................. 5-28
CHECKING THE VALVE SPRINGS......................................................... 5-30
CHECKING THE VALVE LIFTERS .......................................................... 5-31
INSTALLING THE VALVES ..................................................................... 5-31
CYLINDER AND PISTON............................................................................... 5-33
REMOVING THE PISTON ....................................................................... 5-34
CHECKING THE CYLINDER AND PISTON ............................................ 5-34
CHECKING THE PISTON RINGS............................................................ 5-35
CHECKING THE PISTON PIN ................................................................. 5-36
INSTALLING THE PISTON AND CYLINDER .......................................... 5-36

ENGINE REMOVAL
5-1
EASB111194
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.
EASB111195
ENGINE REMOVAL
Removing the exhaust pipe
Order Part name Q’ty Remarks
Refer to “INSTALLING THE EXHAUST
PIPE AND MUFFLER” on page 5-10.
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 4-55.
Connecting arm bolt (frame side)Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 4-55.
1 Silencer clamp 1 Loosen.
2 Silencer 1
3 Exhaust pipe 2 clamp 1 Loosen.
4 Exhaust pipe 2 1
10
5
9
2 6
1
66
3
84 7 (8)
(6)
30 Nm (3.0 m kgf, 22 ft Ibf)T
.R.
30 Nm (3.0 m kgf, 22 ft Ibf)T
.R.
8 Nm (0.8 m kgf, 5.8 ft Ibf)T
.R.
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
New
New
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
20 Nm (2.0 m kgf, 14 ft Ibf)T
.R.
New
7 Nm (0.7 m kgf, 5.1 ft lbf)
10 Nm (1.0 m kgf, 7.2 ft lbf)T
.R.
LT
LT
LT
*
*