checking oil YAMAHA YZ450F 2014 User Guide

REAR BRAKE
4-28
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 pouring the brake fluid, be careful
that water does not enter the reservoir.
Water will significantly lower the boiling
point of the brake fluid and could cause
vapor lock.
ECA13540
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 3-21.
6. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.
7. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
EAS1SL1157
REMOVING 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.
EAS1SL1158CHECKING 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.
EAS1SL1159
a
1
2

REAR BRAKE
4-30
2. Pour brake fluid to the brake fluid reservoir
up to the specified level.
EWA13090
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 pouring the brake fluid, be careful
that water does not enter the reservoir.
Water will significantly lower the boiling
point of the brake fluid and could cause
vapor lock.
ECA13540
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 3-21.
4. Check:
• Brake fluid level
The minimum level mark “a” or below 
Add.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-26.
5. Check:
• Brake pedal operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-21.
Recommended brake fluid
DOT 4
a
a

FRONT FORK
4-40
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
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.
EAS1SL1168CHECKING THE FRONT FORK LEGS
1. Check:
• Inner tube surface “a”
Scratches  Repair or replace.
Use #1000 grit wet sandpaper.
Damaged oil lock piece  Replace.
• Inner tube bends
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 assembly “1”
Bend/damage  Replace.
• O-ring “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
4-57
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.
EAS1SL1180CHECKING 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.
EAS1SL1181
CHECKING 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.
EAS1SL1182INSTALLING THE RELAY ARM
1. Lubricate:
• Oil seals
• Bearing
• Spacers
• Washers
•Collars
2. Install:
• Bearing “1”
• Washer “2”
• Oil seals “3”
(to relay arm “4”)
3. Install:
• Bearing “1”
• Oil seals “2”
(to connecting arm “3”)
1
Recommended lubricant
Lithium-soap-based grease
Installed depth “a”
0 mm (0 in)
Installed depth “a”
0 mm (0 in)
New
3 3
43
2 2
22
a
1
11
New

SWINGARM
4-61
EAS1SL1185REMOVING THE SWINGARM
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. 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.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1186REMOVING THE BEARING
1. Remove:
• Bearing “1”
TIP
Remove the bearing by pressing its outer race.
EAS1SL1187CHECKING THE SWINGARM
1. Check:
• Swingarm
Bends/cracks/damage  Replace.
2. Check:
• Pivot shaft
Roll the pivot shaft on a flat surface.
Bends  Replace.EWA13770
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.
EAS1SL1188
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......................................................................................................... 5-37
REMOVING THE CLUTCH ...................................................................... 5-40
CHECKING THE FRICTION PLATES...................................................... 5-40
CHECKING THE CLUTCH PLATES ........................................................ 5-40
CHECKING THE CLUTCH SPRINGS...................................................... 5-40
CHECKING THE CLUTCH HOUSING ..................................................... 5-41
CHECKING THE CLUTCH BOSS ............................................................ 5-41
CHECKING THE PRESSURE PLATE ..................................................... 5-41
CHECKING THE PUSH LEVER SHAFT .................................................. 5-41
CHECKING THE CLUTCH PUSH RODS ................................................ 5-41
CHECKING THE PRIMARY DRIVE GEAR .............................................. 5-41
CHECKING THE PRIMARY DRIVEN GEAR ........................................... 5-42
INSTALLING THE OIL SEAL................................................................... 5-42
INSTALLING THE RIGHT CRANKCASE COVER ................................... 5-42
INSTALLING THE CLUTCH ..................................................................... 5-42
INSTALLING THE KICKSTARTER LEVER ............................................. 5-45
KICKSTATER................................................................................................. 5-46
REMOVING THE KICK SHAFT ASSEMBLY ........................................... 5-47
CHECKING THE KICK SHAFT AND RATCHET WHEEL ........................ 5-47
CHECKING THE KICK GEAR, KICK IDLE GEAR, 
AND RATCHET WHEEL ......................................................................... 5-47
INSTALLING THE KICK SHAFT ASSEMBLY .......................................... 5-47
INSTALLING THE KICK IDLE GEAR ....................................................... 5-48
SHIFT SHAFT................................................................................................. 5-49
REMOVING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 5-51
REMOVING THE SEGMENT ................................................................... 5-51
CHECKING THE SHIFT SHAFT .............................................................. 5-51
CHECKING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 5-51
CHECKING THE STOPPER LEVER ....................................................... 5-51
INSTALLING THE STOPPER LEVER ..................................................... 5-52
INSTALLING THE SEGMENT.................................................................. 5-52
INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ....... 5-52
INSTALLING THE SHIFT SHAFT ............................................................ 5-53
INSTALLING THE SHIFT PEDAL ............................................................ 5-53
OIL PUMP AND BALANCER GEAR............................................................. 5-54
REMOVING THE BALANCER ................................................................. 5-56
CHECKING THE PRIMARY DRIVE GEAR, BALANCER SHAFT
DRIVE GEAR, AND BALANCER WEIGHT GEAR ................................. 5-56
CHECKING THE BALANCER .................................................................. 5-56
CHECKING THE OIL PUMP .................................................................... 5-56
ASSEMBLING THE OIL PUMP ................................................................ 5-57
INSTALLING THE OIL PUMP AND BALANCER GEAR .......................... 5-57

AC MAGNETO................................................................................................ 5-59
REMOVING THE AC MAGNETO............................................................. 5-60
CHECKING THE AC MAGNETO ............................................................. 5-60
CHECKING THE WOODRUFF KEY ........................................................ 5-60
INSTALLING THE AC MAGNETO ........................................................... 5-60
CRANKCASE................................................................................................. 5-62
DISASSEMBLING THE CRANKCASE..................................................... 5-65
REMOVING THE CRANKCASE BEARING ............................................. 5-65
CHECKING THE TIMING CHAIN, TIMING CHAIN GUIDE,
OIL STRAINER ....................................................................................... 5-65
CHECKING THE CRANKCASE ............................................................... 5-65
ASSEMBLING THE CRANKCASE........................................................... 5-66
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT............................... 5-67
REMOVING THE BALANCER SHAFT..................................................... 5-68
REMOVING THE CRANKSHAFT ASSEMBLY ........................................ 5-68
CHECKING THE CRANKSHAFT ASSEMBLY......................................... 5-68
INSTALLING THE CRANKSHAFT ASSEMBLY....................................... 5-69
TRANSMISSION............................................................................................. 5-70
REMOVING THE TRANSMISSION ......................................................... 5-71
CHECKING THE SHIFT FORKS.............................................................. 5-71
CHECKING THE SHIFT DRUM ASSEMBLY ........................................... 5-72
CHECKING THE TRANSMISSION .......................................................... 5-72
INSTALLING THE TRANSMISSION ........................................................ 5-72

CAMSHAFT
5-16
EAS1SL1212CHECKING THE DECOMPRESSION SYS-
TEM
1. Check:
• Decompression system
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Check that the decompressor cam “1”
moves smoothly.
b. Check that the decompressor lever pin “2”
projects from the camshaft.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SL1213INSTALLING THE CAMSHAFTS
1. Install:
• Exhaust camshaft “1”
• Intake camshaft “2”
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
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.
TIP
Make sure that the alignment mark “c” on the
exhaust camshaft sprocket and the alignment
mark “d” on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
ECA33DD029
NOTICE
Do not turn the crankshaft during the cam-
shaft installation. Damage or improper
valve timing will result.
d. Install the clips, the camshaft caps and the
bolts (camshaft cap).
1
2
Bolt (camshaft cap)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
a
aa
b
a
c 3
d
T R..

VALVES AND VALVE SPRINGS
5-27
TIP
After replacing the valve guide, reface the valve
seat.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Check:
• Valve face
Pitting/wear  Grind the valve face.
• Valve stem end
Mushroom shape or diameter larger than
the body of the valve stem  Replace the
valve.
5. Measure:
• Valve margin thickness D “a”
Out of specification  Replace the valve.
6. Measure:
• Valve stem runout
Out of specification  Replace the valve.
TIP
• When installing a new valve, always replace
the valve guide.
• If the valve is removed or replaced, always re-
place the oil seal.
EAS1SL1222CHECKING THE VALVE SEATS
1. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
2. Check:
• Valve seat
Pitting/wear  Replace the cylinder head.
3. Measure:
• Valve seat width C “a”
Out of specification  Replace the cylinder
head.
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a. Apply Mechanic’s blueing dye (Dykem) “b”
onto the valve face.
Valve guide remover & installer
set (ø5.5)
90890-04016
Valve guide remover (5.5 mm)
YM-01122
Valve guide installer (5.5 mm)
YM-04015
Valve guide reamer (5.5 mm)
YM-01196
Valve margin thickness D (intake)
1.20 mm (0.0472 in)
Valve margin thickness D (ex-
haust)
0.85 mm (0.0335 in)
Valve stem runout
0.010 mm (0.0004 in)
Valve seat width C (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Valve seat width C (exhaust)
0.90–1.10 mm (0.0354–0.0433 in)

CYLINDER AND PISTON
5-33
EAS1SL1227REMOVING THE PISTON
1. Remove:
• Piston pin clip “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.
EAS1SL1228CHECKING 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. Then, find the average of the measure-
ments.
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 D1–D6
Taper limit = (maximum of D1or D2) - (maxi-
mum of D5 or D6)
Out of round limit = maximum of D1, D3 or D5
- minimum of D
2, D4 or D6