2003 YAMAHA YZ450F clutch

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ENGCLUTCH
7. Install:
Pressure plate 1
8. Install:
Clutch spring
Bolt (clutch spring)
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
9. Install:
Gasket (clutch cover) 1
Dowel pin 2
New
10. Install:
Clutch cover 1
Bolt (clutch cover)
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 55
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)
OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)
Extent of removal:1 Oil filter removal2 Water pump removal
3 Crankcase cover (right) removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER, WATER PUMP
AND CRANKCASE COVER
(RIGHT) REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cover Refer to “CLUTCH” section.
1 Oil filter cover 1
2 Oil filter 1
3 Coolant pipe 2 1
4 Water pump housing 1
5 Pin 2
6 Oil delivery pipe 1
1
2
3

4 - 62
ENGBALANCER
BALANCER
BALANCER
Extent of removal:1 Balancer drive gear2 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 (primary drive gear) 1
Refer to “REMOVAL POINTS”.
2 Nut (balancer) 1
3 Lock washer 1
4 Primary drive gear 1
5 Balancer drive gear 1
6 Lock washer 1
7 Balancer driven gear 1
8 Balancer 1 Refer to “REMOVAL POINTS”.
2
1
2

4 - 65
ENGOIL PUMP
OIL PUMP
OIL PUMP
Extent of removal:1 Oil pump removal2 Oil pump disassembly
Extent of removal Order Part name Q’ty Remarks
OIL PUMP REMOVAL AND DIS-
ASSEMBLY
Preparation for removal Clutch housing Refer to “CLUTCH” section.
Crankcase cover (right)Refer to “OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT)” section.
1 Circlip 1
2 Plate washer 1
3 Oil pump drive gear 1
4 Oil pump assembly 1
5 Dowel pin 1
6 Outer rotor 2 1
7 Circlip 1
8 Inner rotor 2 1
9 Pin 1
10 Oil pump cover 1
11 Outer rotor 1 1
12Inner rotor 1
1
2
1

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ENGENGINE REMOVAL
EC4M0000
ENGINE REMOVAL
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for removal Hold the machine by placing the
suitable stand under the frame.
WARNING
Support the machine securely so there is no
danger of it falling over.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Carburetor Refer to “CARBURETOR” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Clutch cable and guide Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Shift pedal Refer to “CDI MAGNETO” section.
Cylinder head breather hose and
oil tank breather hoseRefer to “CAMSHAFTS” section.
Drain the engine oil Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Ignition coil
Disconnect the CDI magneto lead.

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ENGCRANKCASE AND CRANKSHAFT
CRANKCASE AND CRANKSHAFT
CRANKCASE AND CRANKSHAFT
Extent of removal:1 Crankcase separation2 Crankshaft removal
Extent of removal Order Part name Q’ty Remarks
CRANKCASE SEPARATION
Preparation for removal Engine Refer to “ENGINE REMOVAL” section.
Piston Refer to “CYLINDER AND PISTON” sec-
tion.
Balancer Refer to “BALANCER” section.
Kick axle assembly
Refer to “KICK AXLE AND SHIFT
SHAFT” section.
Segment
Stator Refer to “CDI MAGNETO” section.
1 Timing chain guide (rear) 1
2 Timing chain 1
3 Bolt (50 mm) 6
Refer to “REMOVAL POINTS”. 4 Bolt (60 mm) 3
5 Bolt (75 mm) 3
6 Hose guide 1
7 Clutch cable holder 1
8 Crankcase (right) 1
9 Crankcase (left) 1
21

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ENGCRANKCASE AND CRANKSHAFT
REMOVAL POINTS
Crankcase
1. Separate:
Crankcase (right)
Crankcase (left)
Separation steps:
Remove the crankcase bolts, hose guide
and clutch cable holder.
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove
them.
Remove the crankcase (right).
NOTE:
Place the crankcase with its left side
downward and split it by inserting a screw-
driver tip into the splitting slit a in the
crankcase.
Lift the crankcase (right) horizontally while
lightly patting the case splitting slit and
engine mounting boss using a soft ham-
mer, and leave the crankshaft and trans-
mission with the crankcase (left).
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case.
Do not tap on gasket mating surface.
Work slowly and carefully. Make sure the
case halves separate evenly. If one end
“hangs up”, take pressure off the push
screw, realign, and start over. If the
cases do not separate, check for a
remaining case screw or fitting. Do not
force.
Remove the dowel pins and O-ring.
a

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ENGCRANKCASE AND CRANKSHAFT
5. Install:
Dowel pin 1
O-ring 2
Crankcase (right)
To crankcase (left).
NOTE:
Fit the crankcase (right) onto the crankcase
(left). Tap lightly on the case with soft ham-
mer.
When installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).
New
6. Tighten:
Hose guide 1
Clutch cable holder 2
Bolt (clutch cable holder)
Bolt (crankcase)
NOTE:
Tighten the crankcase tightening bolts in
stage, using a crisscross pattern.
7. Install:
Oil delivery pipe
O-ring
Bolt (oil delivery pipe)
8. Install:
Timing chain
Timing chain guide (rear)
Bolt (timing chain guide)
9. Remove:
Sealant
Forced out on the cylinder mating surface.
10. Apply:
Engine oil
To the crank pin, bearing and oil deliv-
ery hole.
11. Check:
Crankshaft and transmission operation.
Unsmooth operation → Repair.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)