checking oil YAMAHA YZ450F 2016 User Guide

REAR BRAKE
4-29
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.
5. Bleed:
• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-22.
6. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-27.
7. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-22.
EASB111156REMOVING THE REAR BRAKE MASTER
CYLINDER
TIP
Before removing the rear brake master cylin-
der, drain the brake fluid from the entire brake
system.
1. Remove:
• Union bolt
• Copper washers
• Brake hose
TIP
To drain any remaining brake fluid, place a con-
tainer under the master cylinder and the end of
the brake hose.
EASB111157CHECKING THE REAR BRAKE MASTER
CYLINDER
1. Check:
• Brake master cylinder “1”
Damage/scratches/wear  Replace.
• Brake fluid delivery passages “2”
(brake master cylinder body)
Obstruction  Blow out with compressed
air.
2. Check:
• Brake master cylinder kit
Damage/wear  Replace.
3. Check:
• Master cylinder reservoir cap
Crack/damage  Replace.
• Brake master cylinder reservoir diaphragm
holder
• Brake master cylinder reservoir diaphragm
Crack/damage  Replace.
4. Check:
• Brake hoses
Cracks/damage/wear  Replace.
a
1
2

REAR BRAKE
4-31
2. Pour brake fluid to the brake fluid reservoir
up to the specified level.
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.
3. Bleed:
• Brake system
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-22.
4. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-27.5. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-22. Specified brake fluid
DOT 4
a
a

FRONT FORK
4-41
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5. Remove:
• Base valve “1”
(from the damper assembly)
TIP
Hold the damper assembly with the cap bolt
ring wrench “2” and use the cap bolt wrench “3”
to remove the base valve.
EASB111167CHECKING THE FRONT FORK LEGS
1. Check:
• Inner tube
Scratches  Repair or replace.
Use #1000 grit wet sandpaper.
Damaged oil lock piece  Replace.
• Outer tube
Out of specification  Replace.
Use the dial gauge “1”.
TIP
The bending value is shown by one half of the
dial gauge reading.
EWA13650
WARNING
Do not attempt to straighten a bent inner
tube as this may dangerously weaken it.
2. Check:
• Outer tube
Scratches/wear/damage  Replace.
3. Measure:
• Fork spring free length “a”
Out of specification  Replace.
4. Check:
• Damper rod “1”
Bend/damage  Replace.
• Damper rod “2”
Wear/damage  Replace.
ECA1DX1010
NOTICE
• The front fork leg has a built-in damper ad-
justing rod and a very sophisticated inter-
nal construction, which are particularly
sensitive to foreign material.
• When disassembling and assembling the
front fork leg, do not allow any foreign ma-
terial to enter the front fork. Cap bolt wrench
90890-01500
YM-01500
Cap bolt ring wrench
90890-01501
YM-01501
Inner tube bending limit
0.2 mm (0.01 in)
1 23
Fork spring free length
497.0 mm (19.57 in)
Limit
492.0 mm (19.37 in)

REAR SHOCK ABSORBER ASSEMBLY
4-59
EASB111178REMOVING THE BEARING
1. Remove:
• Stopper ring (upper bearing) “1”
TIP
Press in the bearing while pressing its outer
race and remove the stopper ring.
2. Remove:
• Upper bearing “1”
TIP
Remove the bearing by pressing its outer race.
3. Remove:
• Lower bearing “1”
TIP
Remove the bearing by pressing its outer race.
EASB111179
CHECKING THE REAR SHOCK ABSORBER
ASSEMBLY
1. Check:
• Rear shock absorber rod
Bends/damage  Replace the rear shock
absorber assembly.
• Rear shock absorber
Gas leaks/oil leaks  Replace the rear
shock absorber assembly.
•Spring
Damage/wear  Replace.
• Spring guide
Damage/wear  Replace.
• Bearing
Damage/wear  Replace.
•Bolts
Bends/damage/wear  Replace.
EASB111180CHECKING THE CONNECTING ARM AND
RELAY ARM
1. Check:
• Connecting arm
• Relay arm
Damage/wear  Replace.
2. Check:
• Bearing
• Spacers
Damage/pitting/scratches  Replace the
bearings and spacers as a set.
3. Check:
• Oil seals
Damage/pitting  Replace.
EASB111181INSTALLING THE RELAY ARM
1. Lubricate:
• Oil seals
• Bearing
• Spacers
• Washers
•Collars
2. Install:
• Bearing “1”
• Washer “2”
• Oil seals “3”
(to relay arm “4”)
1
Recommended lubricant
Molybdenum disulfide grease
Installed depth “a”
0 mm (0 in)
New

SWINGARM
4-63
EASB111184REMOVING THE SWINGARM
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Measure:
• Swingarm side play
• Swingarm vertical movement
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a. Measure the tightening torque of the pivot
shaft nut.
b. Measure the swingarm side play “a” by mov-
ing the swingarm from side to side.
c. If the swingarm side play is out of specifica-
tion, check the spacers, the bearings, and
the collars.
d. Check the swingarm vertical movement “b”
by moving the swingarm up and down.
If swingarm vertical movement is not smooth
or if there is binding, check the spacers, the
bearings, and the collars.
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EASB111185REMOVING THE BEARING
1. Remove:
• Bearing “1”
TIP
Remove the bearing by pressing its outer race.
EASB111186CHECKING THE SWINGARM
1. Check:
• Swingarm
Bends/cracks/damage  Replace.
2. Check:
• Pivot shaft
Roll the pivot shaft on a flat surface.
Bends  Replace.
EWA
WARNING
Do not attempt to straighten a bent pivot
shaft.
3. Wash with kerosene:
• Pivot shaft
• Spacers
•Collars
• Bearing
4. Check:
• Oil seals
Damage  Replace.
• Bearing
• Spacers
Free play exists/unsmooth revolution/rust 
Replace bearing and bushing as a set. Pivot shaft nut
85 Nm (8.5 m·kgf, 61 ft·lbf)
Swingarm end free play limit (ra-
dial)
1.0 mm (0.04 in)
T R..

CLUTCH......................................................................................................... 5-38
REMOVING THE CLUTCH ...................................................................... 5-41
CHECKING THE FRICTION PLATES...................................................... 5-41
CHECKING THE CLUTCH PLATES ........................................................ 5-41
CHECKING THE CLUTCH SPRINGS...................................................... 5-41
CHECKING THE CLUTCH HOUSING ..................................................... 5-42
CHECKING THE CLUTCH BOSS ............................................................ 5-42
CHECKING THE PRESSURE PLATE ..................................................... 5-42
CHECKING THE PUSH LEVER SHAFT .................................................. 5-42
CHECKING THE CLUTCH PUSH RODS ................................................ 5-42
CHECKING THE PRIMARY DRIVE GEAR .............................................. 5-42
CHECKING THE PRIMARY DRIVEN GEAR ........................................... 5-43
INSTALLING THE OIL SEAL................................................................... 5-43
INSTALLING THE RIGHT CRANKCASE COVER ................................... 5-43
INSTALLING THE CLUTCH ..................................................................... 5-44
INSTALLING THE KICKSTARTER LEVER ............................................. 5-46
KICKSTATER................................................................................................. 5-47
REMOVING THE KICK SHAFT ASSEMBLY ........................................... 5-48
CHECKING THE KICK SHAFT AND RATCHET WHEEL ........................ 5-48
CHECKING THE KICK GEAR, KICK IDLE GEAR AND RATCHET
WHEEL .................................................................................................... 5-48
INSTALLING THE KICK SHAFT ASSEMBLY .......................................... 5-48
INSTALLING THE KICK IDLE GEAR ....................................................... 5-49
SHIFT SHAFT................................................................................................. 5-50
REMOVING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 5-52
REMOVING THE SEGMENT ................................................................... 5-52
CHECKING THE SHIFT SHAFT .............................................................. 5-52
CHECKING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 5-52
CHECKING THE STOPPER LEVER ....................................................... 5-52
INSTALLING THE STOPPER LEVER ..................................................... 5-53
INSTALLING THE SEGMENT.................................................................. 5-53
INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ....... 5-53
INSTALLING THE SHIFT SHAFT ............................................................ 5-54
INSTALLING THE SHIFT PEDAL ............................................................ 5-54
OIL PUMP AND BALANCER GEAR............................................................. 5-55
REMOVING THE BALANCER ................................................................. 5-57
CHECKING THE PRIMARY DRIVE GEAR, BALANCER SHAFT
DRIVE GEAR, AND BALANCER WEIGHT GEAR .................................. 5-57
CHECKING THE BALANCER .................................................................. 5-57
CHECKING THE OIL PUMP .................................................................... 5-57
ASSEMBLING THE OIL PUMP ................................................................ 5-58
INSTALLING THE OIL PUMP AND BALANCER GEAR .......................... 5-59

AC MAGNETO................................................................................................ 5-61
REMOVING THE AC MAGNETO............................................................. 5-62
CHECKING THE AC MAGNETO ............................................................. 5-62
CHECKING THE WOODRUFF KEY ........................................................ 5-62
INSTALLING THE AC MAGNETO ........................................................... 5-62
CRANKCASE................................................................................................. 5-64
DISASSEMBLING THE CRANKCASE..................................................... 5-67
REMOVING THE CRANKCASE BEARING ............................................. 5-67
CHECKING THE TIMING CHAIN, TIMING CHAIN GUIDE, OIL
STRAINER .............................................................................................. 5-67
CHECKING THE CRANKCASE ............................................................... 5-68
ASSEMBLING THE CRANKCASE........................................................... 5-68
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT............................... 5-69
REMOVING THE BALANCER SHAFT..................................................... 5-70
REMOVING THE CRANKSHAFT ASSEMBLY ........................................ 5-70
CHECKING THE CRANKSHAFT ASSEMBLY......................................... 5-70
INSTALLING THE CRANKSHAFT ASSEMBLY....................................... 5-71
TRANSMISSION............................................................................................. 5-72
REMOVING THE TRANSMISSION ......................................................... 5-73
CHECKING THE SHIFT FORKS.............................................................. 5-73
CHECKING THE SHIFT DRUM ASSEMBLY ........................................... 5-74
CHECKING THE TRANSMISSION .......................................................... 5-74
INSTALLING THE TRANSMISSION ........................................................ 5-74

CAMSHAFT
5-17
c. If not, replace the tensioner assembly.
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EASB111211CHECKING THE DECOMPRESSION SYS-
TEM
1. Check:
• Decompression system
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a. Check that the decompressor cam “1”
moves smoothly.
b. Check that the decompressor lever pin “2”
projects from the camshaft.
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EASB111212
INSTALLING THE CAMSHAFTS
1. Install:
• Exhaust camshaft “1”
• Intake camshaft “2”
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a. Turn the crankshaft counterclockwise with a
wrench.
TIP
• Apply molybdenum disulfide oil to the cam-
shafts.
• Apply the engine oil on the decompression
system.
• Fill the cylinder head with engine oil up to the
tops “a” of the valve lifters.
b. Align the top dead center (TDC) mark “a” on
the rotor with the alignment mark “b” on the
crankcase cover.
c. Fit the timing chain “3” onto both camshaft
sprockets and install the camshafts on the
cylinder head.
1
2
a
aa
b
a

VALVES AND VALVE SPRINGS
5-31
EASB111223CHECKING THE VALVE LIFTERS
1. Check:
• Valve lifter
Damage/scratches  Replace the valve lift-
ers and cylinder head.
EASB111224INSTALLING THE VALVES
1. Clean:
• Valve stem end
2. Lubricate:
• Valve stem “1”
• Valve stem seal “2”3. Install:
• Spring seat “1”
• Valve stem seal “2”
•Valve “3”
• Valve spring “4”
• Valve spring retainer “5”
(to the cylinder head)
TIP
• Make sure each valve is installed in its original
place.
• Install the valve springs with the larger pitch
“a” facing up.
4. Install:
• Valve cotter “1”
TIP
Install the valve cotters by compressing the
valve spring with the valve spring compressor
“2” and the valve spring compressor adapter
“3”.
Recommended lubricant
Molybdenum disulfide oil
b. Smaller pitch
Valve spring compressor
90890-04019
YM-04019
Valve spring compressor adapter
22 mm
90890-04108
YM-04108
New

CYLINDER AND PISTON
5-34
EASB111226REMOVING THE PISTON
1. Remove:
• Piston pin clips “1”
• Piston pin “2”
• Piston “3”
ECA13810
NOTICE
Do not use a hammer to drive the piston pin
out.
TIP
• Before removing the piston pin clip, cover the
crankcase opening with a cloth to prevent the
piston pin clip from falling into the crankcase.
• Before removing the piston pin, deburr the
piston pin clip’s groove and the piston pin’s
bore area. If the piston pin groove is deburred
and the piston pin is still difficult to remove,
use the piston pin puller set “4”.
2. Remove:
• Top ring
• 2nd ring
• Oil ring
TIP
When removing a piston ring, open the end gap
with your fingers and lift the opposite end gap
of the piston ring over the piston crown.
EASB111227CHECKING THE CYLINDER AND PISTON
1. Check:
• Piston wall (Sidewall)
• Cylinder wall
Vertical scratches  Replace the cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
• Piston-to-cylinder clearance
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the cylinder bore with the cylinder
bore gauge.
TIP
Measure cylinder bore by taking side-to-side
and front-to-back measurements of the cylin-
der. Piston pin puller set
90890-01304
Piston pin puller
YU-01304
1
Bore
97.000–97.010 mm (3.8189–
3.8193 in)
Taper limit
0.050 mm (0.0020 in)
Out of round limit
0.050 mm (0.0020 in)
Cylinder bore = maximum of D
1, D2, D3, D4,
D
5, D6
Taper limit (front-to-back) = maximum differ-
ence between D
1, D3, D5Taper limit (side-to-side) = maximum differ-
ence between D
2, D4, D6
Out of round limit (top) = difference between
D
1, D2Out of round limit (middle) = difference be-
tween D
3, D4Out of round limit (bottom) = difference be-
tween D
5, D6