oil type YAMAHA YZ450F 2008 Owners Manual

1-11
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Concerning the tightening torque, refer to "TIGHTENING TORQUES" section in the CHAPTER 2.
Frame construction Frame to rear frame
Combined seat and fuel tank Fuel tank to frame
Exhaust system Silencer to rear frame
Engine mounting Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering Steering stem to handlebar Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Suspension Front Steering stem to front fork Front fork to upper bracket
Front fork to lower bracket
Rear For link type Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Installation of rear shock absorber Rear shock absorber to frame
Installation of swingarm Tightening of pivot shaft
Wheel Installation of wheel Front Tightening of wheel axle
Tightening of axle holder
Rear Tightening of wheel axle
Wheel to rear wheel sprocket
Brake Front Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Tightening of brake hose holder
Rear Brake pedal to frame
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Tightening of brake hose holder
Fuel system Fuel tank to fuel cock
Lubrication system Tightening of oil hose clamp

2-1
GENERAL SPECIFICATIONS
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model name: YZ450FX (USA, CDN, AUS, NZ)
YZ450F (EUROPE, ZA)
Model code number: 2S2B (USA,CDN)
2S2C (EUROPE)
2S2E (AUS, NZ, ZA)
Dimensions: USA, CDN, AUS, NZ, ZA EUROPE
Overall length 2,194 mm (86.38 in) 2,195 mm (86.42 in)
Overall width 825 mm (32.48 in)
←
Overall height 1,306 mm (51.42 in)←
Seat height 990 mm (38.98 in) 1,001 mm (39.41 in)
Wheelbase 1,495 mm (58.86 in)
←
Minimum ground clearance 374 mm (14.72 in) 375 mm (14.76 in)
Dry weight:
Without oil and fuel 99.5 kg (219 lb)
Engine:
Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 449 cm
3 (15.8 Imp oz, 15.2 US oz)
Bore × stroke 95.0 × 63.4 mm (3.74 × 2.50 in)
Compression ratio 12.3 : 1
Starting system Kickstarter
Lubrication system: Dry sump
Oil type or grade:
Engine oil (For USA and CDN)
Yamalube 4, SAE10W30 or SAE20W40
Yamalube 4-R, SAE10W50
API service SG type or higher,
JASO standard MA
(Except for USA and CDN)
SAE10W30, SAE10W40, SAE15W40,
SAE20W40 or SAE20W50
API service SG type or higher,
JASO standard MA
Oil capacity:
Engine oil
Periodic oil change 0.95 L (0.84 Imp qt, 1.00 US qt)
With oil filter replacement 1.0 L (0.88 Imp qt, 1.06 US qt)
Total amount 1.2 L (1.06 Imp qt, 1.27 US qt)
Coolant capacity (including all routes): 0.99 L (0.87 Imp qt, 1.05 US qt)
Air filter: Wet type element
2

2-2
GENERAL SPECIFICATIONS
Fuel:
Type Premium unleaded gasoline only with a research octane
number of 95 or higher.
Tank capacity 7.0 L (1.54 Imp gal, 1.85 US gal)
Carburetor:
Type FCR-MX39
Manufacturer KEIHIN
Spark plug:
Type/manufacturer CR8E/NGK (resistance type)
Gap 0.7–0.8 mm (0.028–0.031 in)
Clutch type: Wet, multiple-disc
Transmission:
Primary reduction system Gear
Primary reduction ratio 61/23 (2.652)
Secondary reduction system Chain drive
Secondary reduction ratio 49/13 (3.769)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio:
1st 27/14 (1.929)
2nd 23/15 (1.533)
3rd 23/18 (1.278)
4th 24/22 (1.091)
5th 20/21 (0.952)
Chassis: USA, CDN, AUS, NZ, ZA EUROPE
Frame type Semi double cradle
←
Caster angle 26.9° 26.7°
Trail 115.2 mm (4.54 in) 113.8 mm (4.48 in)
Tire:
Type With tube
Size (front) 80/100-21 51M
Size (rear) 120/80-19 63M (For USA, CDN, ZA, AUS, NZ)
110/90-19 62M (For EUROPE)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper

2-6
MAINTENANCE SPECIFICATIONS
Piston off-set 1 mm (0.0394 in) ----
Piston pin bore inside diameter 18.004–18.015 mm (0.7088–0.7093 in) 18.045 mm
(0.7104 in)
Piston pin outside diameter 17.991–18.000 mm (0.7083–0.7087 in) 17.971 mm
(0.7075 in)
Piston rings:
Top ring:
Type Barrel ----
Dimensions (B × T) 1.2 × 3.5 mm (0.05 × 0.14 in) ----
End gap (installed) 0.20–0.30 mm (0.008–0.012 in) 0.55 mm (0.022
in)
Side clearance (installed) 0.030–0.065 mm (0.0012–0.0026 in) 0.12 mm (0.005
in)
2nd ring:
Type Taper ----
Dimensions (B × T) 1.00 × 3.35 mm (0.04 × 0.13 in) ----
End gap (installed) 0.35–0.50 mm (0.014–0.020 in) 0.85 mm (0.033
in)
Side clearance 0.020–0.055 mm (0.0008–0.0022 in) 0.12 mm (0.005
in)
Oil ring:
Dimensions (B × T) 2.0 × 2.9 mm (0.08 × 0.11 in) ----
End gap (installed) 0.2–0.5 mm (0.01–0.02 in) ----
Crankshaft:
Crank width "A" 61.95–62.00 mm (2.439–2.441 in) ----
Runout limit "C" 0.03 mm (0.0012 in) 0.05 mm (0.002
in)
Big end side clearance "D" 0.15–0.45 mm (0.0059–0.0177 in) 0.50 mm (0.02
in)
Small end free play "F" 0.4–1.0 mm (0.02–0.04 in) 2.0 mm (0.08
in)
Balancer:
Balancer drive method Gear ----Item Standard Limit

2-7
MAINTENANCE SPECIFICATIONS
Air filter oil grade: Foam-air-filter oil or equivalent oil ----
Clutch:
Friction plate thickness 2.92–3.08 mm (0.115–0.121 in) 2.8 mm (0.110
in)
Quantity 8 ----
Clutch plate thickness 1.5–1.7 mm (0.059–0.067 in) ----
Quantity 7 ----
Warp limit ---- 0.1 mm (0.004
in)
Clutch spring free length 50.0 mm (1.97 in) 49.0 mm (1.93
in)
Quantity 6 ----
Clutch housing thrust clearance 0.10–0.35 mm (0.0039–0.0138 in) ----
Clutch housing radial clearance 0.010–0.044 mm (0.0004–0.0017 in) ----
Clutch release method Inner push, cam push ----
Shifter:
Shifter type Cam drum and guide bar ----
Guide bar bending limit ---- 0.05 mm (0.002
in)
Kickstarter:
Type Kick and ratchet type ----
Carburetor:
Type/manufacturer FCR-MX39/KEIHIN ----
I. D. mark 2S2B B0 ----
Main jet (M.J) #160 ----
Main air jet (M.A.J) ø2.0 ----
Jet needle - clip position (J.N) NFLR-3 ----
Cutaway (C.A) 1.5 ----
Pilot jet (P.J) #45 ----
Pilot air jet (P.A.J) #100 ----
Pilot outlet (P.O) ø0.9 ----
Pilot screw (example) (P.S) 1-1/2 ----
Bypass (B.P) ø1.0 ----
Valve seat size (V.S) ø3.8 ----
Starter jet (G.S) #72 ----
Leak jet (Acc.P) #55 ----
Float height (F.H) 8 mm (0.31 in) ----
Engine idle speed 1,900–2,100 r/min ----
Intake vacuum 28.0–33.3 kPa (210–250 mmHg, 8.27–
9.84 inHg)----
Hot starter lever free play 3–6 mm (0.12–0.24 in) ----
Lubrication system:
Oil filter type Paper type ----
Oil pump type Trochoid type ----
Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008
in) Item Standard Limit

2-8
MAINTENANCE SPECIFICATIONS
CHASSISSide clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009
in)
Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.17 mm (0.007
in)
Bypass valve setting pressure 40–80 kPa (0.4–0.8 kg/cm
2, 5.69–11.38
psi)----
Cooling:
Radiator core size
Width 120.2 mm (4.73 in) ----
Height 240 mm (9.45 in) ----
Thickness 22 mm (0.87 in) ----
Radiator cap opening pressure 110 kPa (1.1 kg/cm
2, 15.6 psi) ----
Radiator capacity (total) 0.56 L (0.49 Imp qt, 0.59 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit
Item Standard Limit
Steering system:
Steering bearing typeTaper roller bearing ----
Front suspension:
Front fork travel 300 mm (11.8 in) ----
Fork spring free length 454 mm (17.9 in) 449 mm (17.7
in)
Spring rate, STD K = 4.6 N/mm (0.469 kg/mm, 26.3 lb/in) ----
Optional spring Yes ----
Oil capacity 541 cm
3 (19.0 lmp oz, 18.3 US oz) ----
Oil grade Suspension oil "S1" ----
Inner tube outer diameter 48 mm (1.89 in) ----
Front fork top end 5 mm (0.20 in) ----
Rear suspension: USA, CDN, AUS, NZ,
ZAEUROPE
Shock absorber travel 131.5 mm (5.18 in)
←----
Spring free length Approx.275 mm (10.83
in)
←----
Fitting length
One I.D. mark 267 mm (10.51 in) 262 mm (10.31 in) ----
Two I.D. marks 273 mm (10.75 in) 268 mm (10.55 in) ----
Three I.D. marks 264.5 mm (10.41 in) 259.5 mm (10.22 in) ----

One I.D. mark 255.5–273.5 mm
(10.06–10.77 in)
←----
Two I.D. marks 261.5–279.5 mm
(10.30–11.00 in)
←----
Three I.D. marks 253.0–271.0 mm (9.96–
10.67 in)
←----
Spring rate, STD K = 54.0 N/mm (5.50 kg/
mm, 308.0 lb/in)
←----

2-10
TIGHTENING TORQUES
ELECTRICAL
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque tightening after break-in or before each race.
Item Standard Limit
Ignition system:
Advancer type Electrical ----
CDI:
Magneto-model (stator)/manufacturer 2S200/YAMAHA ----
Charging coil 1 resistance (color) 720–1,080
Ωat 20 °C (68 °F) (Green–
Brown)----
Charging coil 2 resistance (color) 44–66
Ωat 20 °C (68 °F) (Black–Pink) ----
Pickup coil resistance (color) 248–372
Ωat 20 °C (68 °F) (White–Red) ----
CDI unit-model/manufacturer 2S2-B0/YAMAHA (Except for EUROPE) ----
2S2-C0/YAMAHA (For EUROPE) ----
Ignition coil:
Model/manufacturer 5TA-10/DENSO ----
Minimum spark gap 6 mm (0.24 in) ----
Primary coil resistance 0.08–0.10
Ωat 20 °C (68 °F) ----
Secondary coil resistance 4.6–6.8 k
Ωat 20 °C (68 °F) ----
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
Spark plug M10S × 1.0 1 13 1.3 9.4
Camshaft cap M6 × 1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12 × 1.0 1 28 2.8 20
Cylinder head (stud bolt) M8 × 1.25 1 15 1.5 11
Cylinder head (bolt) M10 × 1.25 4 Refer to NOTE.
*1
Cylinder head (bolt) M6 × 1.0 2 10 1.0 7.2
Cylinder head cover M6 × 1.0 2 10 1.0 7.2
Cylinder M6 × 1.0 1 10 1.0 7.2
Timing chain tensioner M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner cap bolt M6 × 1.0 1 7 0.7 5.1
Timing chain guide (intake side) M6 × 1.0 2 10 1.0 7.2
Exhaust pipe (nut) M8 × 1.25 1 20 2.0 14
Exhaust pipe (bolt) M8 × 1.25 1 20 2.0 14
△Silencer M8 × 1.25 2 30 3.0 22
Silencer clamp M8 × 1.25 1 14 1.4 10
Exhaust pipe protector M6 × 1.0 3 10 1.0 7.2
Carburetor joint M6 × 1.0 3 10 1.0 7.2
Carburetor joint clamp M4 × 0.7 1 3 0.3 2.2
△Air filter case M6 × 1.0 2 8 0.8 5.8
Air filter joint clamp M6 × 1.0 1 3 0.3 2.2
Air filter joint and air filter case M5 × 0.8 1 4 0.4 2.9
Throttle cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
Throttle cable (pull) M6 × 1.0 1 4 0.4 2.9

3-5
ENGINE
ENGINE
CHECKING THE COOLANT LEVEL
Do not remove the radiator cap
"1", drain bolt and hoses when the
engine and radiator are hot. Scald-
ing hot fluid and steam may be
blown out under pressure, which
could cause serious injury. When
the engine has cooled, place a
thick towel over the radiator cap,
slowly rotate the cap counter-
clockwise to the detent. This pro-
cedure allows any residual
pressure to escape. When the
hissing sound has stopped, press
down on the cap while turning
counterclockwise and remove it.
Hard water or salt water is harmful
to the engine parts. You may use
distilled water, if you can't get soft
water.
1. Place the machine on a level
place, and hold it in an upright po-
sition.
2. Remove:
• Radiator cap
3. Check:
• Coolant level "a"
Coolant level low
→Add coolant.
1. Radiator
CHANGING THE COOLANT
Do not remove the radiator cap
when the engine is hot.
Take care so that coolant does not
splash on painted surfaces. If it
splashes, wash it away with water.
1. Place a container under the en-gine.
2. Remove:
• Engine guard "1"
• Coolant drain bolt "2"
3. Remove:
• Radiator cap
Drain the coolant completely.
4. Clean:
• Cooling system
Thoroughly flush the cooling sys-
tem with clean tap water.
5. Install:
• Copper washer
• Coolant drain bolt
• Engine guard
• Bolt (engine guard)
6. Fill:
• Radiator
•Engine
To specified level.
• Do not mix more than one type of
ethylene glycol antifreeze con-
taining corrosion inhibitors for
aluminum engine.
• Do not use water containing im-
purities or oil.
Handling notes of coolant:
The coolant is harmful so it should be
handled with special care.
• When coolant splashes to your
eye.
Thoroughly wash your eye with
water and see your doctor.
• When coolant splashes to your
clothes.
Quickly wash it away with water
and then with soap.
• When coolant is swallowed.
Quickly make him vomit and take
him to a doctor.
7. Install:
• Radiator cap
Start the engine and warm it up
for a several minutes.
8. Check:
• Coolant level
Coolant level low
→Add coolant.
CHECKING THE RADIATOR CAP
1. Inspect:
• Seal (radiator cap) "1"
• Valve and valve seat "2"
Crack/damage
→Replace.
Exist fur deposits "3"
→Clean or
replace.
CHECKING THE RADIATOR CAP
OPENING PRESSURE
1. Attach:
• Radiator cap tester "1" and adapt-
er "2"
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (engine guard):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Recommended coolant:
High quality ethylene
glycol anti-freeze con-
taining anti-corrosion
for aluminum engine
Coolant "1" and water
(soft water) "2" mixing ra-
tio:
50%/50%
Coolant capacity:
0.99 L (0.87 Imp qt, 1.05
US qt)
Radiator cap tester:
YU-24460-01/90890-
01325
Radiator cap tester
adapter:
YU-33984/90890-01352

3-8
ENGINE
CHECKING THE ENGINE OIL
LEVEL
1. Stand the machine on a level sur-
face.
• When checking the oil level make
sure that the machine is upright.
• Place the machine on a suitable
stand.
Never remove the oil tank cap just
after high speed operation. The
heated oil could spurt out. causing
danger. Wait until the oil cools
down to approximately 70°C
(158°F).
2. Idle the engine more than 3 min-
utes while keeping the machine
upright. Then stop the engine and
inspect the oil level.
3. Remove:
• Oil tank cap 1
4. Inspect:
• Oil level
Check that the engine oil is above
the level mark "a" and that the oil
does not come out when the
check bolt "1" is removed.
Below the level mark "a"
→Add oil
through the filler cap hole until it is
above the level mark "a".
Oil comes out at the check bolt
→
Drain the oil until it stops coming
out.
When inspecting the oil level, do not
screw the oil level gauge into the oil
tank. Insert the gauge lightly.
(For USA and CDN)
• Do not add any chemical addi-
tives. Engine oil also lubricates
the clutch and additives could
cause clutch slippage.
• Do not allow foreign material to
enter the crankcase.
(Except for USA and CDN)
• Do not add any chemical addi-
tives or use oils with a grade of
CD "a" or higher.
• Do not use oils labeled "ENERGY
CONSERVING II" "b" or higher.
Engine oil also lubricates the
clutch and additives could cause
clutch slippage.• Do not allow foreign material to
enter the crankcase.
5. Start the engine and let it warm up
for several minutes.
When the oil tank is empty, never
start the engine.
6. Idle the engine more than 10 sec-
onds while keeping the machine
upright. Then stop the engine and
add the oil to the maximum level.
7. Install:
• Oil tank cap
CHANGING THE ENGINE OIL
1. Start the engine and let it warm up
for several minutes.
2. Stop the engine and place an oil
pan under the drain bolt.
3. Remove:
• Oil tank plug "1"
• Oil filler cap "2"
• Drain bolt (with gasket) "3"
• Oil filter drain bolt (O-ring) "4"
• Drain bolt (with gasket) "5"
Drain the crankcase and oil tank
of its oil.
4. If the oil filter is to be replaced dur-
ing this oil change, remove the fol-
lowing parts and reinstall them.
Recommended oil:
Yamalube 4,
SAE10W30 or
SAE20W40
Yamalube 4-R,
SAE10W50
API service SG type or
higher, JASO standard
MA
Recommended oil:
SAE10W30,
SAE10W40,
SAE15W40, SAE20W40
or SAE20W50
API service SG type or
higher, JASO standard
MA

5-14
FRONT BRAKE AND REAR BRAKE
4. Install:
• Copper washer "1"
• Brake hose "2"
• Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake master cylinder.
INSTALLING THE REAR BRAKE
HOSE
1. Install:
• Copper washer "1"
• Brake hose "2"
• Union bolt "3"
Always use new copper washers.
Install the brake hose so that its
pipe portion "a" directs as shown
and lightly touches the projection
"b" on the brake caliper.
2. Install:
• Brake hose holder "1"
• Screw (brake hose holder) "2"
After installing the brake hose
holders, make sure the brake hose
does not contact the spring (rear
shock absorber). If it does, correct
its twist.
FILLING THE BRAKE FLUID
1. Fill:
•Brake fluid
Until the fluid level reaches
"LOWER" level line "a".
• Use only the designated quality
brake fluid:
otherwise, the rubber seals may
deteriorate, causing leakage and
poor brake performance.
• Refill with the same type of brake
fluid;
mixing fluids may result in a
harmful chemical reaction and
lead to poor performance.
• Be careful that water does not
enter the master cylinder when
refilling. Water will significantly lower the boiling point of the flu-
id and may result in vapor lock.
Brake fluid may erode painted sur-
faces or plastic parts. Always
clean up spilled fluid immediately.
A. Front
B. Rear
2. Air bleed:
• Brake system
Refer to "BLEEDING THE HY-
DRAULIC BRAKE SYSTEM" sec-
tion in the CHAPTER 3.
3. Inspect:
• Brake fluid level
Fluid at lower level
→Fill up.
Refer to "CHECKING THE
BRAKE FLUID LEVEL" section in
the CHAPTER 3.
4. Install:
• Reservoir float (front brake)
• Diaphragm
• Brake master cylinder cap "1"
• Screw (brake master cylinder
cap) "2"
After installation, while pulling the
brake lever in or pushing down on
the brake pedal, check whether
there is any brake fluid leaking
where the union bolts are installed
respectively at the brake master
cylinder and brake caliper.
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Union bolt:
30 Nm (3.0 m•kg, 22
ft•lb)
Screw (brake hose hold-
er):
2 Nm (0.2 m•kg, 1.4
ft•lb)
Recommended brake flu-
id:
DOT #4
Screw (bolt) {brake mas-
ter cylinder cap}:
2 Nm (0.2 m•kg, 1.4
ft•lb)