2007 YAMAHA YZ450F magneto

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND SIDE
COVERS ....................................................4-1
EXHAUST PIPE AND SILENCER .............4-3
RADIATOR ................................................4-6
CARBURETOR ..........................................4-9
CAMSHAFTS ...........................................4-22
CYLINDER HEAD ....................................4-30
VALVES AND VALVE SPRINGS ............4-34
CYLINDER AND PISTON ........................4-43
CLUTCH ...................................................4-49
OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT) ..............4-56
BALANCER .............................................4-63
OIL PUMP ................................................4-66
KICK AXLE AND SHIFT SHAFT .............4-70
CDI MAGNETO ........................................4-78
ENGINE REMOVAL .................................4-81
CRANKCASE AND CRANKSHAFT ........4-86
TRANSMISSION, SHIFT CAM AND
SHIFT FORK ............................................4-95
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL .......5-1
FRONT BRAKE AND REAR BRAKE .....5-10
FRONT FORK ..........................................5-26
HANDLEBAR ...........................................5-43
STEERING ...............................................5-49
SWINGARM .............................................5-54
REAR SHOCK ABSORBER ....................5-62

GEN
INFO
1 - 7
SPECIAL TOOLS
EC140001
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.
NOTE:
For U.S.A. and Canada, use part number starting with “YM-”, “YU-” or “ACC-”.
For others, use part number starting with “90890-”.
Part number Tool name/How to use Illustration
YU-3097, 90890-01252
YU-1256Dial gauge and stand
Stand
These tools are used to check each part for runout or
bend.YU-3097
YU-125690890-01252
YU-90050, 90890-01274
YU-90050, 90890-01275
YU-91044, 90890-04081
YU-90063, 90890-01278Crankshaft installing tool
Crankshaft installing pot
Crankshaft installing bolt
Spacer (crankshaft installer)
Adapter (M12)
These tools are used to install the crankshaft.YU-90050
YU-90063
YU-9104490890-01274
90890-01275
90890-01278
90890-04081
YU-1304, 90890-01304 Piston pin puller
This tool is used to remove the piston pin.YU-1304 90890-01304
YU-24460-01, 90890-01325
YU-33984, 90890-01352Radiator cap tester
Adapter
These tools are used for checking the cooling sys-
tem.YU-24460-01
YU-3398490890-01325
90890-01352
YM-04151, 90890-04151 Rotor puller
This tool is used to remove the flywheel magneto.YM-04151 90890-04151
YU-33975, 90890-01403 Ring nut wrench
This tool is used when tighten the steering ring nut to
specification.YU-33975 90890-01403
YM-01500, 90890-01500 Cap bolt wrench
This tool is used to loosen or tighten the base valve.YM-01500 90890-01500

SPEC
2 - 3 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,
ZA, AUS, NZEUR
(Except for F)F
Frame type Semi double
cradle← ←
Caster angle 26.8°← 26.9°
Trail 114.1 mm
(4.49 in)115.3 mm
(4.54 in)116.3 mm
(4.58 in)
Tire:
Type With tube
Size (front) 80/100-21 51M (For USA, CDN, ZA, AUS, NZ
and F)
80/100-21 51R (For EUROPE except F)
Size (rear) 110/90-19 62M (For USA, CDN, ZA, AUS, NZ
and F)
110/90-19 NHS (For EUROPE except F)
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
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto
GENERAL SPECIFICATIONS

SPEC
2 - 17
EC212300
ELECTRICAL
Item Standard Limit
Ignition system:
Advancer type Electrical ----
C.D.I.:
Magneto-model (stator)/manufacturer 2S200/YAMAHA ----
Source coil 1 resistance (color) 720 ~ 1,080 Ω at 20 °C (68 °F)
(Green – Brown)----
Source coil 2 resistance (color) 44 ~ 66 Ω at 20 °C (68 °F)
(Black – Pink)----
Pickup coil resistance (color) 248 ~ 372 Ω at 20 °C (68 °F)
(White – Red)----
CDI unit-model/manufacturer 2S2-70/YAMAHA (Except for
EUROPE)
2S2-80/YAMAHA (For EUROPE)----
----
Ignition coil:
Model/manufacturer 5TA-10/DENSO ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.08 ~ 0.10 Ω at 20 °C (68 °F) ----
Secondary winding resistance 4.6 ~ 6.8 kΩ at 20 °C (68 °F) ----
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Stator M6 × 1.0 3 10 1.0 7.2
Rotor M12 × 1.25 1 56 5.6 40
Neutral switch M5 × 0.8 2 4 0.4 2.9
MAINTENANCE SPECIFICATIONS

2 - 22
SPECCABLE ROUTING DIAGRAM
1Hot starter cable
2Clamp
3TPS (throttle position sensor)
lead
4Hump (frame)
5Neutral switch lead
6Engine bracket
7Engine skid plate stay
8CDI magneto lead
9Clutch cable
0Radiator breather hose
ARadiator hose 2
B“ENGINE STOP” button leadCSub wire harness
DGround lead
ECDI unit bracket
FCDI unit
GCable guide
HIgnition coil lead
IThrottle cable
ÈFasten the hot starter cable and
throttle cables onto the frame.
Locate the clamp ends under
the hot starter cable.ÉFasten the hot starter cable,
throttle cables, TPS lead and
ignition coil lead to the frame.
ÊFasten the TPS lead to the
frame behind its hump.
ËPass the TPS lead over the hot
starter cable.
ÌPass the neutral switch lead on
the inside of the engine bracket.
ÍPass the neutral switch lead
over the engine skid plate stay.
C-C
G-G
E
2
Õ
4 58E
É
D GGA
AB
D
5
ÌÍ Í
Í Î
F
E
D
2
2
2
Ï Ð Ò
Ñ Ó
1
G
2
3
4 2
0
8
5
9
8Ë Ê
0
0 8 5
CC
B
È 2
9
FF
Ô
Ô
B-B
A-A
I
H
3
1
C
B
A
0
0
8
5
D-D
3 F-F
6
7
2 5 0

2 - 23
SPECCABLE ROUTING DIAGRAM
ÎFasten the neutral switch lead
and radiator breather hose to
the frame.
ÏFasten the neutral switch lead,
CDI magneto lead and radiator
breather hose to the frame.
ÐFasten the neutral switch lead,
CDI magneto lead, radiator
breather hose and clutch cable
to the frame over the radiator
mounting boss.ÑPass the radiator breather hose
in front of the radiator hose 2, on
the left of the chassis, and then
between the frame and radiator
hose 4.
ÒFasten the sub wire harness and
“ENGINE STOP” button lead to
the CDI unit bracket with the
clamp ends facing downward
behind the location where the
ground lead branches out from
the sub wire harness.ÓFasten the ground lead and
cable guide together to the CDI
unit bracket.
ÔLocate the clamp ends in the
arrowed range.
ÕFasten the neutral switch lead
and CDI magneto lead to the
frame over its hump.
C-C
G-G
E
2
Õ
4 58E
É
D GGA
AB
D
5
ÌÍ Í
Í Î
F
E
D
2
2
2
Ï Ð Ò
Ñ Ó
1
G
2
3
4 2
0
8
5
9
8Ë Ê
0
0 8 5
CC
B
È 2
9
FF
Ô
Ô
B-B
A-A
I
H
3
1
C
B
A
0
0
8
5
D-D
3 F-F
6
7
2 5 0

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
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.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-13
Engine oilCheck that the oil level is correct. Check the crankcase and oil
line for leakage.P.3-13 ~ 17
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9 ~ 10
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-24 ~ 30
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-31 ~ 33
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-41 ~ 42
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-42 ~ 44
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-33 ~ 40
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.—
Muffler Check that the muffler is tightly mounted and has no cracks.—
Sprocket Check that the driven sprocket tightening bolt is not loose. P.3-31
Lubrication Check for smooth operation. Lubricate if necessary. P.3-45
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-18
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 21

4 - 63
ENGBALANCER
BALANCER
BALANCER
Extent of removal:
1 Balancer drive gear
2 Balancer
Extent of removal Order Part name Q’ty Remarks
BALANCER REMOVAL
Preparation for removal Clutch housing Refer to “CLUTCH” section.
Crankcase cover (right) Refer to “OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT)” section.
Stator Refer to “CDI MAGNETO” section.
1 Nut (balancer) 1
Refer to “REMOVAL POINTS”. 2 Nut (primary drive gear) 1
3 Nut (balancer driven gear) 1
4 Lock washer 1
5 Balancer 1
6 Straight key 1
7 Conical washer 1
8 Primary drive gear 1
9 Balancer drive gear 1
10 Lock washer 1
11 Balancer driven gear 1
2
1
2
1