2004 YAMAHA WR 450F oil

4 - 81
ENG
5. Install:
Bolt (starter clutch) 1
Plain washer (rotor)
Nut (rotor) 2
Use the sheave holder 3.
NOTE:
Tighten the rotor nut to 65 Nm (6.5 m·kg,
47 ft·lb), loosen and retighten the rotor nut to
65 Nm (6.5 m·kg, 47 ft·lb).
Sheave holder:
YS-1880-A/90890-01701
1
1
3
2
T R..16 Nm (1.6 m · kg, 11 ft · lb)
T R..65 Nm (6.5 m · kg, 47 ft · lb)
6. Install:
Shaft 1
Bearing 2
Idle gear 2 3
NOTE:
Apply the engine oil on the shaft, bearing and
idle gear inner circumference.
7. Install:
Dowel pin
Gasket [crankcase cover (left)]
Crankcase cover (left) 1
Bolt [crankcase cover (left)]
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
8. Install:
Plain washer
Torque limiter 1
Plain washer
NOTE:
Apply the engine oil to the shaft and plain
washers.1
AC MAGNETO AND STARTER CLUTCH

4 - 83
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.
WARNINGSupport the machine securely so there is no
danger of it falling over.
Drain the engine oil Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
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 the engine side.
Radiator Refer to “RADIATOR” section.
Shift pedal Refer to “AC MAGNETO AND
STARTER CLUTCH” section.
Cylinder head breather hose and
oil tank breather hoseRefer to “CAMSHAFTS” section.
Ignition coil
Disconnect the AC magneto lead.

4 - 84
ENGENGINE REMOVAL
Extent of removal:1 Engine removal
Extent of removal Order Part name Q’ty Remarks
Crankcase cover (left) Refer to “AC MAGNETO AND
STARTER CLUTCH” section for remov-
ing the starter motor lead.
Disconnect the starter motor
lead.Refer to “ELECTRIC STARTING SYS-
TEM” section in the CHAPTER 6.
Negative battery lead Disconnect at the starter motor side.
1 Engine skid plate (front) 1
2 Neutral switch 1
3 Oil hose 2
4 Chain cover 1
5 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 6 Lock washer 1
7 Drive sprocket 1
8 Clip 1
9 Bolt (brake pedal) 1
10 Brake pedal 1
1

4 - 88
ENGENGINE REMOVAL
Drive sprocket
1. Install:
Drive sprocket 1
Drive chain 2
NOTE:
Install the drive sprocket together with the
drive chain.
2. Install:
Lock washer 1
Nut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
New
T R..75 Nm (7.5 m · kg, 54 ft · lb)
3. Bend the lock washer tab to lock the nut.
4. Install:
Chain guide
Chain cover 1
Screw (chain cover) 2
5. Install:
O-ring 1
Dowel pin 2
Oil hose 3
Bolt (oil hose) 4
NOTE:
Apply the lithium soap base grease on the O-
ring.
6. Install:
Spring 1
Pin 2
O-ring 3
Neutral switch 4
Screw (neutral switch) 5
NOTE:
Apply the lithium soap base grease on the O-
ring.
21T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
New
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
New
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)

4 - 90
ENGCRANKCASE AND CRANKSHAFT
Extent of removal Order Part name Q’ty Remarks
10 Oil strainer 1
11 Oil delivery pipe 2 1
12 Crankshaft 1 Use special tool.
Refer to “REMOVAL POINTS”.
2

4 - 91
ENGCRANKCASE AND CRANKSHAFT
CRANKCASE BEARING
Extent of removal:1 Crankcase bearing removal
Extent of removal Order Part name Q’ty Remarks
CRANKCASE BEARING
REMOVAL
Preparation for removal Transmission
Shift cam and shift forkRefer to “TRANSMISSION, SHIFT
CAM AND SHIFT FORK” section.
1 Oil seal 3
2 Bearing 10 Refer to “REMOVAL POINTS”.
1

4 - 93
ENGCRANKCASE AND CRANKSHAFT
Crankshaft
1. Remove:
Crankshaft 1
Use the crankcase separating tool 2.
CAUTION:
Do not use a hammer to drive out the
crankshaft.
Crankshaft bearing
1. Remove:
Bearing 1
NOTE:
Remove the bearing from the crankcase by
pressing its inner race.
Do not use the removed bearing.
Crankcase separating tool:
YU-1135-A/90890-01135
INSPECTION
Timing chain and timing chain guide
1. Inspect:
Timing chain
Cracks/stiff → Replace the timing chain
and camshaft sprocket as a set.
2. Inspect:
Timing chain guide
Wear/damage → Replace.
EC4N4101
Crankcase
1. Inspect:
Contacting surface a
Scratches → Replace.
Engine mounting boss b, crankcase
Cracks/damage → Replace.
2. Inspect:
Bearing
Rotate inner race with a finger.
Rough spot/seizure → Replace.
3. Inspect:
Oil seal
Wear/damage → Replace.

4 - 94
ENGCRANKCASE AND CRANKSHAFT
EC4N4201
Crankshaft
1. Measure:
Runout limit a
Small end free play limit b
Connecting rod big end side clearance
c
Crank width d
Out of specification → Replace.
Use the dial gauge and a thickness
gauge.
Dial gauge and stand:
YU-3097/90890-01252
Standard
Runout
limit:0.03 mm
(0.0012 in)0.05 mm
(0.002 in)
Small end
free play:0.4 ~ 1.0 mm
(0.016 ~ 0.039 in)2.0 mm
(0.08 in)
Side
clearance:0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)0.50 mm
(0.02 in)
Crack
width:61.95 ~ 62.00 mm
(2.439 ~ 2.441 in)—
Oil strainer
1. Inspect:
Oil strainer
Damage → Replace.
Oil delivery pipe 2
1. Inspect:
Oil delivery pipe 2
Cracks/damage → Replace.
Oil delivery pipe holes 1
Clogged → Blow out with compressed
air.