2008 YAMAHA WR 450F radiator

CONTENTS
CHAPTER 1
GENERAL INFOR-
MATION
DESCRIPTION ................. 1-1
MACHINE
IDENTIFICATION ............. 1-2
INCLUDED PARTS .......... 1-2
IMPORTANT
INFORMATION................. 1-2
CHECKING OF CONNEC-
TION ................................. 1-3
SPECIAL TOOLS ............. 1-4
CONTROL FUNCTIONS .. 1-8
MULTI-FUNCTION
DISPLAY .......................... 1-9
STARTING AND
BREAK-IN ...................... 1-14
TORQUE-CHECK
POINTS........................... 1-16
CLEANING AND
STORAGE ...................... 1-17
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICA-
TIONS ............................... 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-4
TIGHTENING
TORQUES ...................... 2-13
LUBRICATION
DIAGRAMS .................... 2-19
CABLE ROUTING
DIAGRAM ....................... 2-21
CHAPTER 3
REGULAR INSPEC-
TION AND AD-
JUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-17
ELECTRICAL ................. 3-27
CHAPTER 4
TUNING
ENGINE ............................ 4-1
CHASSIS .......................... 4-5
CHAPTER 5
ENGINE
RADIATOR ....................... 5-1
CARBURETOR................. 5-4
AIR INDICTOIN
SYSTEM ......................... 5-13
CAMSHAFTS.................. 5-15
CYLINDER HEAD........... 5-20
VALVES AND VALVE
SPRINGS ........................ 5-23
CYLINDER AND
PISTON ........................... 5-27
CLUTCH ......................... 5-30
OIL FILTER ELEMENT
AND WATER PUMP ....... 5-34
BALANCER .................... 5-38
OIL PUMP ....................... 5-40
KICK SHAFT AND SHIFT
SHAFT ............................ 5-43
AC MAGNETO AND
STARTER CLUTCH ....... 5-48
ENGINE REMOVAL ....... 5-53CRANKCASE AND
CRANKSHAFT ...............5-57
TRANSMISSION, SHIFT
CAM AND SHIFT
FORK ..............................5-63
CHAPTER 6
CHASSIS
FRONT WHEEL AND
REAR WHEEL ..................6-1
FRONT BRAKE AND
REAR BRAKE ..................6-6
FRONT FORK .................6-16
HANDLEBAR..................6-23
STEERING ......................6-27
SWINGARM ....................6-31
REAR SHOCK
ABSORBER ....................6-36
CHAPTER 7
ELECTRICAL
ELECTRICAL COMPO-
NENTS AND WIRING DIA-
GRAM ...............................7-1
IGNITION SYSTEM...........7-3
ELECTRIC STARTING
SYSTEM............................7-5
CHARGING SYSTEM .....7-13
THROTTLE POSITION
SENSOR SYSTEM .........7-15
LIGHTING SYSTEM .......7-18
SIGNALING SYSTEM.....7-20

1-1
DESCRIPTION
GENERAL INFORMATION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
1. Clutch lever
2. Hot starter lever
3. Engine stop switch
4. Multi-function display
5. Main switch
6. Start switch
7. Front brake lever
8. Throttle grip
9. Radiator cap
10. Fuel tank cap
11. Taillight
12. Kickstarter crank
13. Fuel tank14. Headlight
15. Radiator
16. Coolant drain bolt
17. Rear brake pedal
18. Valve joint
19. Fuel cock
20. Cold starter knob
21. Air cleaner
22. Catch tank
23. Drive chain
24. Shift pedal
25. Oil dipstick
26. Front fork
1

1-4
SPECIAL TOOLS
SPECIAL TOOLS
The proper special tools are necessary for complete and accurate tune-up and assembly. Using the correct special tool will
help prevent damage caused by the use of improper tools or improvised techniques. The shape and part number used for
the special tool differ by country, so two types are provided. Refer to the list provided to avoid errors when placing an order.
• For U.S.A. and Canada, use part number starting with "YM-", "YU-" or "ACC-".
• For others, use part number starting with "90890-".
Tool name/Part number How to use Illustration
Dial gauge and stand
YU-3097, 90890-01252
Stand
YU-1256These tools are used to check each
part for runout or bent.
Crankshaft installing tool
Crankshaft installing pot
YU-90050, 90890-01274
Crankshaft installing bolt
YU-90050, 90890-01275
Spacer (crankshaft installer)
YM-91044, 90890-04081
Adapter (M12)
YU-90063, 90890-01278These tools are used to install the
crankshaft.
Piston pin puller set
YU-1304, 90890-01304 This tool is used to remove the pis-
ton pin.
Radiator cap tester
YU-24460-01, 90890-01325
Radiator cap tester adapter
YU-33984, 90890-01352These tools are used for checking
the cooling system.
Steering nut wrench
YU-33975, 90890-01403 This tool is used when tighten the
steering ring nut to specification.

2-9
MAINTENANCE SPECIFICATIONS
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)
Side 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
(0.0067 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 (Left/Right) 260 mm (10.24 in)/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) 0.57 L (0.50 Imp qt, 0.60 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit

2-13
TIGHTENING TORQUES
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque tightening after break-in or before each race.
*1: Tighten the cylinder head bolts to 30 Nm (3.0 m•kg, 22 ft•lb) in the proper tightening sequence, remove and retighten
the cylinder head bolts to 20 Nm (2.0 m•kg, 14 ft•lb) in the proper tightening sequence, and then tighten the cylinder head
bolts further to reach the specified angle 180° in the proper tightening sequence.
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 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
Air induction pipe M6 × 1.0 2 10 1.0 7.2
Air cut-off valve assembly and bracket M6 × 1.0 2 10 1.0 7.2
Bracket (air cut-off valve) and frame M6 × 1.0 2 7 0.7 5.1
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
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
Hot starter cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
Air filter element M6 × 1.0 1 2 0.2 1.4
Radiator stay M6 × 1.0 6 7 0.7 5.1
Radiator M6 × 1.0 4 10 1.0 7.2
Radiator hose clamp M6 × 1.0 8 2 0.2 1.4

2-14
TIGHTENING TORQUES
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 2 10 1.0 7.2
Oil pump drive gear shaft M6 × 1.0 1 10 1.0 7.2
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 check bolt (cylinder head) M6 × 1.0 1 10 1.0 7.2
△Oil hose clamp — 2 2 0.2 1.4
Crankshaft end accessing screw M27 × 1.5 1 10 1.0 7.2
Timing mark accessing screw M14 × 1.5 1 6 0.6 4.3
Clutch cover M6 × 1.0 7 10 1.0 7.2
Crankcase cover (right) M6 × 1.0 8 10 1.0 7.2
Crankcase cover (right) M6 × 1.0 2 12 1.2 8.7
Crankcase cover (left) M6 × 1.0 8 10 1.0 7.2
Idle gear cover (starter motor) M6 × 1.0 2 10 1.0 7.2
Crankcase M6 × 1.0 12 12 1.2 8.7
Clutch cable holder M6 × 1.0 1 10 1.0 7.2
Oil drain bolt (crankcase right) M6 × 1.25 1 20 2.0 14
Oil drain bolt (crankcase left) M6 × 1.0 1 20 2.0 14
Oil check bolt (crankcase) M6 × 1.0 1 10 1.0 7.2
Oil strainer M6 × 1.0 1 10 1.0 7.2
Crankcase bearing stopper M6 × 1.0 4 14 1.4 10
Crankcase bearing stopper M6 × 1.0 8 10 1.0 7.2
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kickstarter crank M8 × 1.25 1 33 3.3 24
Screw (kickstarter crank) M6 × 1.0 1 7 0.7 5.1
Starter clutch M6 × 1.0 6 16 1.6 11
Primary drive gear M20 × 1.0 1 110 11.0 80
Clutch boss M20 × 1.0 1 75 7.5 54
Clutch cable adjust bolt and locknut M8 × 1.0 1 4 0.4 2.9
Clutch spring M6 × 1.0 6 10 1.0 7.2
Balancer M10 × 1.0 1 45 4.5 32
Balancer driven gear M14 × 1.0 1 50 5.0 36
Balancer weight plate M6 × 1.0 3 10 1.0 7.2
Drive sprocket M20 × 1.0 1 75 7.5 54
Drive chain sprocket cover M6 × 1.0 2 8 0.8 5.8
Shift pedal M6 × 1.0 1 12 1.2 8.7
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb

2-16
TIGHTENING TORQUES
△Driven sprocket and wheel hub M8 × 1.25 6 50 5.0 36
△Nipple (spoke) — 72 3 0.3 2.2
△Disc cover and rear brake caliper M6 × 1.0 2 10 1.0 7.2
△Protector and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Chain puller adjust bolt and locknut M8 × 1.25 2 19 1.9 13
Engine mounting:
△Engine upper bracket and frame M10 × 1.25 4 55 5.5 40
△Engine lower bracket and frame M8 × 1.25 4 34 3.4 24
△Engine and engine bracket (lower) M10 × 1.25 1 53 5.3 38
△Engine and engine bracket (upper) M10 × 1.25 1 55 5.5 40
△Engine and frame (lower) M10 × 1.25 1 53 5.3 38
△Engine guard M6 × 1.0 3 7 0.7 5.1
Regulator mounting M6 × 1.0 2 7 0.7 5.1
△Pivot shaft and nut M16 × 1.5 1 85 8.5 61
△Relay arm and swingarm M14 × 1.5 1 70 7.0 50
△Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
△Connecting rod and frame M14 × 1.5 1 80 8.0 58
△Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
△Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
△Rear frame and frame (upper) M8 × 1.25 1 38 3.8 27
△Rear frame and frame (lower) M8 × 1.25 2 32 3.2 23
△Swingarm and brake hose holder M5 × 0.8 4 2 0.2 1.4
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Drive chain tensioner mounting (upper) M8 × 1.25 1 16 1.6 11
Drive chain tensioner mounting (lower) M8 × 1.25 1 16 1.6 11
Chain support and swingarm M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
△Fuel tank mounting M6 × 1.0 2 9 0.9 6.5
△Fuel tank and fuel cock M6 × 1.0 2 4 0.4 2.9
Fuel tank and seat set bracket M6 × 1.0 1 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
△Seat mounting M8 × 1.25 2 23 2.3 17
△Side cover mounting M6 × 1.0 2 7 0.7 5.1
△Air scoop and fuel tank M6 × 1.0 6 7 0.7 5.1
△Air scoop and radiator panel (lower) M6 × 1.0 2 6 0.6 4.3
△Front fender mounting M6 × 1.0 4 7 0.7 5.1
△Rear fender mounting(front) M6 × 1.0 2 7 0.7 5.1
△Rear fender mounting (rear) M6 × 1.0 2 11 1.1 8.0
Multi-function display bracket mounting M6 × 1.0 2 7 0.7 5.1
Multi-function display mounting M5 × 0.8 2 4 0.4 2.9
Plate 1 and protector M5 × 0.8 2 4 0.4 2.9
Plate 2 and protector — 2 0.5 0.05 0.36
Speed sensor lead holder and under bracket M6 × 1.0 1 13 1.3 9.4
Headlight body and headlight unit — 2 1 0.1 0.7Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb

3-2
MAINTENANCE INTERVALS
CLUTCH
Inspect and adjust●●Inspect housing, friction plate, clutch
plate and spring.
Replace●
TRANSMISSION
Inspect●
Replace bearing●
SHIFT FORK, SHIFT CAM,
GUIDE BAR
Inspect●Inspect wear.
ROTOR NUT
Retighten●●
MUFFLER
Inspect and retighten●●
Clean●
Replace●
CRANK
Inspect and clean●●
CARBURETOR
Inspect, adjust and clean●●
AIR INDUCTION SYSTEM
Inspect and clean●● ●●
SPARK PLUG
Inspect and clean●●
Replace●
DRIVE CHAIN Use chain lube.
Lubricate, slack, alignment●●Chain slack: 48–58 mm (1.9–2.3 in)
Replace●
COOLING SYSTEM
Check coolant level and leakage●●
Check radiator cap operation●
Replace coolant●Every two years
Inspect hoses●
OUTSIDE NUTS AND BOLTS
Retighten●●Refer to "STARTING AND BREAK-
IN" section in the CHAPTER 1.
AIR FILTER
Clean and lubricate●●Use foam air-filter oil or equivalent oil.
Replace●
OIL FILTER
Replace●●
FRAME
Clean and inspect●● ItemAfter
break-
inEvery
race
Every
third
(or 500
km)Every
fifth (or
1,000
km)
As re-
quiredRemarks
3