2005 YAMAHA WR 450F carburetor

5. GASOLINE IS HIGHLY FLAMMABLE.
Always turn off the engine while refu-
eling. Take care to not spill any gaso-
line on the engine or exhaust system.
Never refuel in the vicinity of an open
flame, or while smoking.
6. GASOLINE CAN CAUSE INJURY.
If you should swallow some gasoline,
inhale excess gasoline vapors, or
allow any gasoline to get into your
eyes, contact a doctor immediately. If
any gasoline spills onto your skin or
clothing, immediately wash skin
areas with soap and water, and
change your clothes.
7. ONLY OPERATE THE MACHINE IN AN
AREA WITH ADEQUATE VENTILA-
TION.
Never start the engine or let it run for
any length of time in an enclosed
area. Exhaust fumes are poisonous.
These fumes contain carbon monox-
ide, which by itself is odorless and
colorless. Carbon monoxide is a dan-
gerous gas which can cause uncon-
sciousness or can be lethal.
8. PARK THE MACHINE CAREFULLY;
TURN OFF THE ENGINE.
Always turn off the engine if you are
going to leave the machine. Do not
park the machine on a slope or soft
ground as it may fall over.
9. THE ENGINE, EXHAUST PIPE, MUF-
FLER, AND OIL TANK WILL BE VERY
HOT AFTER THE ENGINE HAS BEEN
RUN.
Be careful not to touch them or to
allow any clothing item to contact
them during inspection or repair.
10. PROPERLY SECURE THE MACHINE
BEFORE TRANSPORTING IT.
When transporting the machine in
another vehicle, always be sure it is
properly secured and in an upright
position and that the fuel cock is in
the “OFF” position. Otherwise, fuel
may leak out of the carburetor or fuel
tank.

CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS ..................................4-1
EXHAUST PIPE AND SILENCER .............4-3
RADIATOR ................................................4-5
CARBURETOR ..........................................4-8
AIR INDUCTION SYSTEM ......................4-21
CAMSHAFTS ...........................................4-23
CYLINDER HEAD ....................................4-32
VALVES AND VALVE SPRINGS ............4-36
CYLINDER AND PISTON ........................4-45
CLUTCH ...................................................4-51
OIL FILTER, WATER PUMP
AND CRANKCASE COVER (RIGHT) .....4-58
BALANCER .............................................4-65
OIL PUMP ................................................4-68
KICK AXLE AND SHIFT SHAFT .............4-72
AC MAGNETO
AND STARTER CLUTCH ........................4-79
ENGINE REMOVAL .................................4-86
CRANKCASE AND CRANKSHAFT ........4-92
TRANSMISSION, SHIFT CAM
AND SHIFT FORK .................................4-101
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL .......5-1
FRONT BRAKE AND REAR BRAKE .....5-10
FRONT FORK ..........................................5-26
HANDLEBAR ...........................................5-39
STEERING ...............................................5-46
SWINGARM .............................................5-52
REAR SHOCK ABSORBER ....................5-60

1 - 12
GEN
INFO
CONTROL FUNCTIONS
EC157000
REAR BRAKE PEDAL
The rear brake pedal 1 is located on the right
side of the machine. Press down on the brake
pedal to activate the rear brake.
FUEL COCK
The fuel cock supplies fuel from the tank to
carburetor and also filters the fuel. The fuel
cock has three positions:
OFF: With the lever in this position fuel will
not flow. Always return the lever to this
position when the engine is not running.
ON: With the lever in this position fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
RES: With the lever in this position fuel flows
to the carburetor from the reserve sec-
tion of the fuel tank after the main sup-
ply of the fuel has been depleted.
Normal riding is possible with the lever
is in this position, but it is recommended
to add fuel as soon as possible.
COLD STARTER KNOB
When cold, the engine requires a richer air-fuel
mixture for starting. A separate starter circuit,
which is controlled by the cold starter knob 1,
supplies this mixture. Pull the cold starter knob
out to open the circuit for starting. When the
engine has warmed up, push it in to close the
circuit.
HOT STARTER LEVER
The hot starter lever 1 is used when starting a
warm engine.
Use the hot starter lever when starting the
engine again immediately after it was stopped
(the engine is still warm). Pulling the hot starter
lever injects secondary air to thin the air-fuel
mixture temporarily, allowing the engine to be
started more easily.

1 - 15
GEN
INFO
STARTING AND BREAK-IN
STARTING AND BREAK-IN
WARNING
Never start or run the engine in a closed
area. The exhaust fumes are poisonous;
they can cause loss of consciousness and
death in a very short time. Always operate
the machine in a well-ventilated area.
CAUTION:
The carburetor on this machine has a
built-in accelerator pump. Therefore,
when starting the engine, do not operate
the throttle or the spark plug will foul.
Unlike a two-stroke engine, this engine
cannot be kick started when the throttle is
open because the kickstarter may kick
back. Also, if the throttle is open the air/
fuel mixture may be too lean for the
engine to start.
Before starting the machine, perform the
checks in the pre-operation check list.
AIR FILTER MAINTENANCE
According to “AIR FILTER CLEANING” section
in the CHAPTER 3, apply the foam-air-filter oil
or its equivalent to the element. (Excess oil in
the element may adversely affect engine start-
ing.)
STARTING A COLD ENGINE
NOTE:
This model is equipped with an ignition circuit
cut-off system. The engine can be started
under the following conditions.
When the transmission is in neutral.
When the clutch is disengaged with the
transmission in any position. However, it is
recommended to shift into neutral before
starting the engine.
1. Inspect the coolant level.
2. Turn the fuel cock to “ON”.
3. Push the main switch to “ON”.
4. Shift the transmission into neutral.
5. Fully open the cold starter knob 1.
6. Start the engine by pushing the start switch
or by kicking the kickstarter.

SPEC
2 - 2 Oil capacity:
Engine oil
Periodic oil change 1.0 L (0.88 Imp qt, 1.06 US qt)
With oil filter replacement 1.1 L (0.97 Imp qt, 1.16 US qt)
Total amount 1.2 L (1.06 Imp qt, 1.27 US qt)
Coolant capacity (including all routes): 1.56 L (1.37 Imp qt, 1.65 US qt)
Air filter: Wet type element
Fuel:
Type Premium unleaded gasoline only with a
research octane number of 95 or higher.
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
Reserve 1.1 L (0.24 Imp gal, 0.29 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 62/22 (2.818)
Secondary reduction system Chain drive
Secondary reduction ratio 50/14 (3.571)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio: 1st 29/12 (2.416)
2nd 26/15 (1.733)
3rd 21/16 (1.312)
4th 21/20 (1.050)
5th 21/25 (0.840)
Chassis: USA, ZA, CDN EUROPE, AUS, NZ
Frame type Semi double cradle←
Caster angle 27.4°27.3°
Trail 120 mm (4.72 in) 119 mm (4.69 in)
Tire:
Type With tube
Size (front) 80/100-21 51M (USA, CDN, ZA)
90/90-21 54R (EUROPE, AUS, NZ)
Size (rear) 110/100-18 64M (USA, CDN, ZA)
130/90-18 69R (EUROPE, AUS, NZ)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
GENERAL SPECIFICATIONS

2

SPEC
2 - 8 Clutch:
Friction plate thickness 2.92 ~ 3.08 mm
(0.115 ~ 0.121 in)2.8 mm
(0.110 in)
Quantity 8 ----
Clutch plate 1 thickness 1.9 ~ 2.1 mm (0.075 ~ 0.083 in) ----
Quantity 4 ----
Warp limit ---- 0.1 mm
(0.004 in)
Clutch plate 2 thickness 1.5 ~ 1.7 mm (0.059 ~ 0.067 in) ----
Quantity 3 ----
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 Ratchet type ----
Carburetor:
I. D. mark 5TJ8 80 ----
Main jet (M.J) #165 ----
Main air jet (M.A.J)ø2.0 ----
Jet needle (J.N) NFNT ----
Cutaway (C.A) 1.5 ----
Pilot jet (P.J) #45 ----
Pilot air jet (P.A.J) #80 ----
Pilot outlet (P.O)ø0.9 ----
Bypass (B.P)ø1.0 ----
Valve seat size (V.S)ø3.8 ----
Starter jet (G.S) #65 ----
Leak jet (Acc.P) #50 ----
Float height (F.H) 8 mm (0.31 in) ----
Engine idle speed 1,700 ~ 1,900 r/min ----
Intake vacuum 34.3 ~ 40.7 kPa
(260 ~ 300 mmHg,
10.24 ~ 11.81 inHg)----
Hot starter lever free play 3 ~ 6 mm (0.12 ~ 0.24 in) ----Item Standard Limit
MAINTENANCE SPECIFICATIONS

SPEC
2 - 11 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) M6 × 1.0 2 7 0.7 5.1
M8 × 1.25 1 15 1.5 11
(bolt) M10 × 1.25 4 Refer to NOTE.*
1
(nut) 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
Tensioner cap bolt M6 × 1.0 1 7 0.7 5.1
Timing chain guide (rear) M6 × 1.0 2 10 1.0 7.2
Exhaust pipe (nut) M8 × 1.25 1 13 1.3 9.4
(bolt) M8 × 1.25 1 24 2.4 17
Silencer M8 × 1.25 2 35 3.5 25
Silencer clamp M8 × 1.25 1 16 1.6 11
Exhaust pipe protector M6 × 1.0 3 10 1.0 7.2
Spark arrester M5 × 0.8 4 7 0.7 5.1
Silencer cap M5 × 0.8 6 5 0.5 3.6
Carburetor joint clamp (cylinder head side) M5 × 0.8 1 3 0.3 2.2
Carburetor joint clamp (carburetor side) 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 (pull) M6 × 1.0 1 4 0.4 2.9
Throttle cable (return) M12 × 1.0 1 11 1.1 8.0
Throttle cable cover M5 × 0.8 2 4 0.4 2.9
Hot starter plunger M12 × 1.0 1 2 0.2 1.4
Radiator panel (upper) M6 × 1.0 2 10 1.0 7.2
Radiator M6 × 1.0 6 10 1.0 7.2
Radiator hose clamp M6 × 1.0 8 2 0.2 1.4
Radiator pipe 1, 2 M10 × 1.0 2 10 1.0 7.2
Impeller M8 × 1.25 1 14 1.4 10
Water pump housing cover M6 × 1.0 3 10 1.0 7.2
Coolant drain bolt M6 × 1.0 1 10 1.0 7.2
Oil pump cover M4 × 0.7 1 2 0.2 1.4
Oil pump M6 × 1.0 3 9 0.9 6.5
Engine oil drain bolt (oil filter) M6 × 1.0 1 10 1.0 7.2
Oil filter cover M6 × 1.0 2 10 1.0 7.2
Oil delivery pipe 1 M10 × 1.25 1 20 2.0 14
M8 × 1.25 2 18 1.8 13
Oil delivery pipe 2 M6 × 1.0 1 10 1.0 7.2
Oil hose M6 × 1.0 2 8 0.8 5.8
MAINTENANCE SPECIFICATIONS

2 - 23
SPECCABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1Fuel tank breather hose
2Clamp
3Diode
4Wire harness
5Hot starter cable
6Negative battery lead
7Starter motor lead
8TPS (throttle position sensor)
lead
9Cylinder head breather hose
0Neutral switch lead
AOil hose
BAC magneto lead
COil tank breather hose
DRectifier/regulator lead
EBrake hose
FHose guideGCarburetor breather hose
HOverflow hose
ICoolant reservoir tank breather
hose
ÈInsert the fuel tank breather
hose into the hole in the steer-
ing shaft cap.
ÉUsing a plastic locking tie, fas-
ten the diode of the wire har-
ness (at the white tape) and the
neutral switch coupler to the
frame, and cut off the tie end.ÊFasten the wire harness, cool-
ant reservoir hose and hot
starter cable to the frame with a
plastic locking tie and cut off the
tie end.
ËFasten the wire harness and
coolant reservoir hose to the
frame with a plastic locking tie
and cut off the tie end.
ÌFasten the wire harness to the
frame at its white tape with a
plastic locking tie and cut off the
tie end.
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