2014 YAMAHA YZ450F oil pressure

TIGHTENING TORQUES
2-14
EAS1SL1057ENGINE TIGHTENING TORQUES
TIP
- marked portion shall be checked for torque tightening after break-in or before each race.
ITEMThread
sizeQ’tyTIGHTENING TORQUESRemarks
Camshaft cap boltM6810 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder head blind plugM12128 Nm (2.8 m·kgf, 20 ft·lbf)
Spark plugM10113 Nm (1.3 m·kgf, 9.4 ft·lbf)
Cylinder head stud bolt (exhaust
pipe)M637 Nm (0.7 m·kgf, 5.1 ft·lbf)
Cylinder head boltsM94See TIP.*1
Cylinder head boltsM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder head cover boltM6310 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil passage plug (cylinder head)M8115 Nm (1.5 m·kgf, 11 ft·lbf)
Cylinder boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil pressure check boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Balancer weight plate screwM6310 Nm (1.0 m·kgf, 7.2 ft·lbf)
Balancer driven gear nutM14150 Nm (5.0 m·kgf, 36 ft·lbf)
Use a
lock
washer.
Balancer nutM10145 Nm (4.5 m·kgf, 33 ft·lbf)
Use a
lock
washer.
Timing chain guide stopper plate
(exhaust side)M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Timing chain tensioner cap boltM616 Nm (0.6 m·kgf, 4.3 ft·lbf)
Timing chain tensioner boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Coolant drain boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator hose clamp screwM681.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Radiator boltM6410 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator pipe bolt M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator pipe joint bolt M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Water pump housing cover boltM6410 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil pump boltM525 Nm (0.5 m·kgf, 3.6 ft·lbf)
Oil pump cover screwM412.0 Nm (0.20 m·kgf, 1.4 ft·lbf)
Oil strainer boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil passage cover bolt (left crank-
case)M6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Throttle cable cover boltM513.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Throttle body joint boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Throttle body joint clamp boltM513.0 Nm (0.30 m·kgf, 2.2 ft·lbf)
Air filter joint clamp boltM413.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Air filter case boltM637 Nm (0.7 m·kgf, 5.1 ft·lbf)
LT
M
LT
LT
LT

TIGHTENING TORQUES
2-16
Drive sprocket nutM20175 Nm (7.5 m·kgf, 54 ft·lbf)
Use a
lock
washer.
Drive axle oil seal stopper boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
SegmentM8130 Nm (3.0 m·kgf, 22 ft·lbf)
Shift guide boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
Stopper lever boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Shift pedal boltM6110 Nm (1.0 m·kgf, 7.2 ft·lbf)
Rotor nutM12165 Nm (6.5 m·kgf, 47 ft·lbf)
Stator screwM538 Nm (0.8 m·kgf, 5.8 ft·lbf)
Crankshaft position sensor boltM6210 Nm (1.0 m·kgf, 7.2 ft·lbf)
AC magneto lead holder boltM518 Nm (0.8 m·kgf, 5.8 ft·lbf)
Coolant temperature sensorM10116 Nm (1.6 m·kgf, 12 ft·lbf)
Neutral switch boltM523.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Intake air temperature sensor screwM511.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Rectifier/regulator boltM627 Nm (0.7 m·kgf, 5.1 ft·lbf)
ECU boltM523.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Ignition coil boltM627 Nm (0.7 m·kgf, 5.1 ft·lbf)
Throttle position sensor screwM523.4 Nm (0.34 m·kgf, 2.5 ft·lbf)
Intake air pressure sensor screwM615 Nm (0.5 m·kgf, 3.6 ft·lbf)
ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks
LT
LT
LT
LT
LT
LT
LT

LUBRICATION SYSTEM CHART AND DIAGRAMS
2-32
1. Camshaft
2. Oil pressure check bolt3. Oil filter element
4. Oil pump

3
PERIODIC CHECKS AND ADJUSTMENTS
MAINTENANCE INTERVALS.......................................................................... 3-1
MAINTENANCE INTERVALS .................................................................... 3-1
PRE-OPERATION INSPECTION AND MAINTENANCE................................. 3-7
GENERAL INSPECTION AND MAINTENANCE........................................ 3-7
ENGINE............................................................................................................ 3-8
CHECKING THE COOLANT LEVEL .......................................................... 3-8
CHECKING THE COOLING SYSTEM ....................................................... 3-8
CHANGING THE COOLANT...................................................................... 3-8
CHECKING THE RADIATOR CAP ............................................................ 3-9
CHECKING THE RADIATOR CAP OPENING PRESSURE ...................... 3-9
CHECKING THE COOLANT CIRCULATORY SYSTEM FOR LEAKS .... 3-10
ADJUSTING THE CLUTCH LEVER POSITION ...................................... 3-10
ADJUSTING THE CLUTCH LEVER FREE PLAY .................................... 3-10
ADJUSTING THE THROTTLE GRIP FREE PLAY .................................. 3-11
LUBRICATING THE THROTTLE CABLE ................................................ 3-12
CLEANING THE AIR FILTER ELEMENT................................................. 3-12
CHECKING THE THROTTLE BODY JOINT ............................................ 3-13
CHECKING THE BREATHER HOSES .................................................... 3-13
CHECKING THE EXHAUST SYSTEM..................................................... 3-13
CHECKING THE FUEL LINE ................................................................... 3-14
CHECKING THE ENGINE OIL LEVEL..................................................... 3-14
CHANGING THE ENGINE OIL ................................................................ 3-15
ADJUSTING THE ENGINE IDLING SPEED ............................................ 3-16
ADJUSTING THE VALVE CLEARANCE ................................................. 3-17
CHASSIS........................................................................................................ 3-21
BLEEDING THE BRAKE SYSTEM .......................................................... 3-21
CHECKING THE BRAKE HOSE .............................................................. 3-22
ADJUSTING THE FRONT BRAKE .......................................................... 3-22
ADJUSTING THE REAR BRAKE ............................................................. 3-23
CHECKING THE FRONT BRAKE PADS ................................................. 3-23
CHECKING THE REAR BRAKE PADS ................................................... 3-25
CHECKING THE REAR BRAKE PAD INSULATOR ................................ 3-26
CHECKING THE BRAKE FLUID LEVEL.................................................. 3-26
ADJUSTING THE DRIVE CHAIN SLACK ................................................ 3-27
CHECKING THE FRONT FORK LEGS ................................................... 3-28
CHECKING THE FRONT FORK PROTECTOR GUIDE .......................... 3-28
CLEANING THE FRONT FORK OIL SEAL AND DUST SEAL ................ 3-28
AIR BLEEDING FROM FRONT FORK .................................................... 3-28
ADJUSTING THE FRONT FORK LEGS .................................................. 3-29
CHECKING THE SWINGARM OPERATION ........................................... 3-30
CHECKING THE REAR SUSPENSION ................................................... 3-30
ADJUSTING THE REAR SHOCK ABSORBER ASSEMBLY ................... 3-30
CHECKING THE TIRES ........................................................................... 3-32
CHECKING AND TIGHTENING THE SPOKES ....................................... 3-32
CHECKING THE WHEELS ...................................................................... 3-33

PRE-OPERATION INSPECTION AND MAINTENANCE
3-7
EAS1SL1067
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EAS1SL1068GENERAL INSPECTION AND MAINTENANCE
TIP
Perform usual maintenance enough so that, in the race course, a confirmation of that and simple set-
ting adjustments may only be left, in order to get enough time to use effectively.
ITEMinspectPage
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.3-8 – 10
FuelCheck that a fresh gasoline is filled in the fuel tank.
Check the fuel line for leakage.1-22
Engine oilCheck that the oil level is correct. Check the crank-
case and oil line for leakage.3-14 – 16
Gear shifter and clutchCheck that gears can be shifted correctly in order and
that the clutch operates smoothly.3-10 – 11
Throttle grip/Housing
Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and
housing, if necessary.
3-11 – 12
BrakesCheck the play of front brake and effect of front and
rear brake.3-21 – 27
Drive chainCheck drive chain slack and alignment. Check that
the drive chain is lubricated properly.3-27
4-64 – 65
WheelsCheck for excessive wear and tire pressure. Check
for loose spokes and have no excessive play.3-32 – 33
SteeringCheck that the handlebar can be turned smoothly and
have no excessive play.3-33 – 34
Front forks and rear
shock absorberCheck that they operate smoothly and there is no oil
leakage.3-28 – 32
Cables (wires)
Check that the clutch and throttle cables move
smoothly. Check that they are not caught when the
handlebars are turned or when the front forks travel
up and down.
—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and
has no cracks.3-13 – 14
Rear wheel sprocketCheck that the rear wheel sprocket tightening bolt is
not loose.4-8 – 9
LubricationCheck for smooth operation. Lubricate if necessary. 3-12 , 3-34
Bolts and nutsCheck the chassis and engine for loose bolts and
nuts.1-25 – 26
Lead connectorsCheck that the AC magneto, ECU and ignition coil are
connected tightly.1-12 – 14
Settings
Is the machine set suitably for the condition of the rac-
ing course and weather or by taking into account the
results of test runs before racing? Are inspection and
maintenance completely done?10-1 – 8

ENGINE
3-16
7. Pour the specified amount of engine oil into
the oil filler cap hole.
8. Install:
• Oil filler cap
9. Check:
• Oil level
Refer to “CHECKING THE ENGINE OIL
LEVEL” on page 3-14.
10.Check:
• Engine oil pressure
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Slightly loosen the oil pressure check bolt
“1.”
EWA
WARNING
When the engine is started with the check
bolt removed, oil will spout; therefore, al
-
ways loosen it before the checkup.
Start the engine and keep it idling until oil
starts to seep from the oil pressure check
bolt.
EWA
WARNING
Always keep the engine idling speed during
the checkup without increasing the engine
speed.
ECA
NOTICE
If no engine oil seeps out after one minute,
immediately turn the engine off so it will not
seize.
b. If no engine oil seeps out, check the engine
oil for leaks, and the engine oil passage and
the oil pump for damage.
c. Check the oil pressure again.
d. Tighten the oil pressure check bolt.
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EAS1SL1087ADJUSTING THE ENGINE IDLING SPEED
TIP
• Because the air pressure is lower at high alti-
tudes, the air-fuel mixture will become richer.
If the idling speed is low, turn the starter knob/
idle screw a few clicks counterclockwise to in
-
crease the speed before the adjustment.
• Before adjusting the engine idling speed,
make sure that the air filter element is not
clogged, the engine compression is proper,
and the throttle grip free play is proper.
• Adjust the engine idling speed with the starter
knob/idle screw pushed in completely.
1. Start the engine, and warm this up until the
oil has reached the specified temperature.
2. Attach the pocket tester with temperature
probe “1” to the oil drain bolt.
3. Install:
• Digital tachometer
Engine oil quantity
With oil filter element replace-
ment
0.69 L (0.73 US qt, 0.61 Imp.qt)
Quantity (disassembled)
0.95 L (1.00 US qt, 0.84 Imp.qt)
1
Oil pressure check bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil temperature
55-65 °C (131–149 °F)
Digital tachometer
90890-06760
YU-39951-B
T R..
1

CHASSIS
3-28
EAS1SL1099CHECKING THE FRONT FORK LEGS
1. Stand the vehicle upright on a level surface.EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Inner tube
Damage/scratches  Replace.
• Front fork leg (s)
Oil leaks between inner tube and outer tube
 Replace the oil seal.
3. Hold the vehicle upright and apply the front
brake.
4. Check:
• Front fork operation
Push down hard on the handlebar several
times and check if the front fork rebounds
smoothly.
Unsmooth operation  Correct or replace.
Refer to “FRONT FORK” on page 4-37.
EAS1SL1100CHECKING THE FRONT FORK PROTEC-
TOR GUIDE
1. Check:
• Protector guide “1”
Out of specification  Replace.
TIP
The protector guide reaches the limit of its use
when it is worn down to the same height “a” as
of the outer tube circumference.
EAS1SL1101
CLEANING THE FRONT FORK OIL SEAL
AND DUST SEAL
1. Remove:
•Protector
• Dust seal “1”ECA?
NOTICE
Be careful not to damage the dust seal and
the inner tube by a driver.
2. Clean:
• Dust seal “a”
• Oil seal “b”
TIP
• Clean the dust seal and oil seal after every
run.
• Apply lithium-soap-based grease on the inner
tube.
EAS1SL1102AIR BLEEDING FROM FRONT FORK
TIP
If the front fork initial movement feels stiff dur-
ing a run, relieve the front fork internal pres-
sure.
1. Use a suitable stand to raise the front wheel
off the ground.
EWA@
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Remove the air bleed screw “1” and release
the internal pressure from the front fork.
1
a
1
LS
a
b

FRONT FORK
4-42
4. Measure:
• Oil level (left and right) “a”
Out of specification  Regulate.
5. Tighten:
• Locknut “1”
TIP
Fully finger tighten the locknut onto the damper
assembly.
6. Loosen:
• Compression damping force adjuster “1”
TIP
• Before loosening the damping force adjuster,
record the setting position.
• Unless the damping force adjuster is fully
loosened, correct damping characteristic can
-
not be obtained after installation.
7. Install:
• Base valve “1”
(to the damper assembly “2”)
TIP
First bring the damper rod pressure to a maxi-
mum. Then install the base valve while releas-
ing the damper rod pressure.
8. Check:
• Damper assembly
Not fully stretched  Repeat the steps 1 to
7.
9. Tighten:
• Base valve “1”
TIP
Hold the damper assembly with the cap bolt
ring wrench “2” and use the cap bolt wrench “3”
to tighten the base valve.
Standard oil level
145-148 mm (5.71-5.83 in)
From top of fully stretched
damper assembly.
1
a
Base valve
28 Nm (2.8 m·kgf, 20 ft·lbf)
1
1
2
T R..