warning YAMAHA WR 450F 2003 Owner's Manual

4 - 6
ENG

RADIATOR
EC456000
HANDLING NOTE
WARNING

Do not remove the radiator cap when the
engine and radiator are hot. Scalding hot
fluid and steam may be blown out under
pressure, which could cause serious
injury.
When the engine has cooled, open the radi-
ator cap by the following procedure:
Place a thick rag, like a towel, over the radi-
ator cap, slowly rotate the cap counter-
clockwise to the detent. This procedure
allows any residual pressure to escape.
When the hissing sound has stopped,
press down on the cap while turning coun-
terclockwise and remove it.
EC454000
INSPECTION
EC444100
Radiator
1. Inspect:
Radiator core 1
Obstruction → Blow out with com-
pressed air through rear of the radiator.
Bent fin → Repair/replace.
EC455000
ASSEMBLY AND INSTALLATION
Radiator
1. Install:
Pipe 1 1
Hose 1 2
Pipe 2 3
Hose 3 4
Hose 4 5
2. Install:
Hose 2 1
Radiator (left) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

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.
WARNING
Support 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.

5 - 1
CHAS

EC500000
CHASSIS
EC590000
FRONT WHEEL AND REAR WHEEL
EC598000
FRONT WHEEL
FRONT WHEEL AND REAR WHEEL
Extent of removal:
1
Front wheel removal
2
Wheel bearing removal
3
Brake disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
FRONT WHEEL REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING

Support the machine securely so there is no
danger of it falling over.
1 Trip meter cable 1
2 Hose cover 1
3 Bolt (brake hose holder) 2 Only loosening.
4 Bolt (axle holder) 4 Only loosening.
5 Nut (front wheel axle) 1
6 Front wheel axle 1
7 Front wheel 1
8 Trip meter gear unit 1
9 Collar 1
10 Oil seal 1
11 Bearing 2 Refer to “REMOVAL POINTS”.
12 Brake disc 1
2
31
3

5 - 2
CHAS

EC598100
REAR WHEEL
Extent of removal:
1
Rear wheel removal
2
Wheel bearing removal
3
Brake disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
REAR WHEEL REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING

Support the machine securely so there is no
danger of it falling over.
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Driven sprocket 1
7 Oil seal 2
8 Circlip 1
9 Bearing 2 Refer to “REMOVAL POINTS”.
10Brake disc
1
2
31
3

FRONT WHEEL AND REAR WHEEL

5 - 4
CHAS

FRONT WHEEL AND REAR WHEEL
EC514200
Wheel axle
1. Measure:

Wheel axle bends
Out of specification
→
Replace.
Use the dial gauge
1
.
NOTE:

The bending value is shown by one half of the
dial gauge reading.
WARNING

Do not attempt to straighten a bent axle.
Wheel axle bending limit:
0.5 mm (0.020 in)
EC594200
Brake disc
1. Measure:

Brake disc deflection (only rear brake
disc)
Use the dial gauge
1
.
Out of specification
→
Inspect wheel
runout.
If wheel runout is in good condition,
replace the brake disc.
2. Measure:

Brake disc thickness
a

Out of limit
→
Replace.
Disc deflection limit:
Standard <Limit>
Rear —0.15 mm
(0.006 in)
Disc wear limit:
Standard <Limit>
Front 3.0 mm (0.12 in) 2.5 mm (0.10 in)
Rear 4.0 mm (0.16 in) 3.5 mm (0.14 in)

5 - 11
CHASFRONT BRAKE AND REAR BRAKE
EC5A0000
FRONT BRAKE AND REAR BRAKE
EC5A8000
FRONT BRAKE
Extent of removal:1 Brake hose removal2 Caliper removal
3 Master cylinder removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Hose cover 1
2 Brake hose holder 1
3 Bolt (brake hose holder) 2 Only loosening.
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the caliper.
8 Caliper 1
9 Brake lever 1
10 Master cylinder bracket 1
11 Master cylinder 1
2
3
1
3
2

5 - 12
CHAS
EC5A8100
REAR BRAKE
Extent of removal:1 Master cylinder removal2 Brake hose removal
3 Caliper removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Drain the brake fluid. Refer to “REMOVAL POINTS”.
1 Brake pedal 1
2 Master cylinder 1
3 Brake hose holder 2
4 Union bolt 2
5 Brake hose 1
6 Pad pin plug 1 Remove when loosening the pad pin.
7 Pad pin 1 Loosen when disassembling the caliper.
8Caliper
1
3
1
321
FRONT BRAKE AND REAR BRAKE

5 - 15
CHASFRONT BRAKE AND REAR BRAKE
EC5A3000
REMOVAL POINTS
Brake fluid
1. Remove:
[Front]
Master cylinder cap 1
[Rear]
Master cylinder cap 1
Protector
NOTE:
Do not remove the diaphragm.
ÅFront
ıRear
2. Connect the transparent hose 2 to the
bleed screw 1 and place a suitable con-
tainer under its end.
ÅFront
ıRear
Å
ı
3. Loosen the bleed screw and drain the
brake fluid while pulling the lever in or
pushing down on the pedal.
ACHTUNG:CAUTION:
Do not reuse the drained brake fluid.
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled
fluid immediately.
EC533301
Caliper piston
1. Remove:
Caliper piston
Use compressed air and proceed care-
fully.
WARNING
Cover piston with rag and use extreme
caution when expelling piston from cylin-
der.
Never attempt to pry out piston.
ÅFront
ıRear
Caliper piston removal steps:
Insert a piece of rag into the caliper to lock
one caliper.
Carefully force the piston out of the caliper
cylinder with compressed air.
ı
Å
Å
ı

5 - 16
CHASFRONT BRAKE AND REAR BRAKE
EC533402
Piston seal kit
1. Remove:
Dust seal 1
Piston seal 2
NOTE:
Remove the piston seals and dust seals by
pushing them with a finger.
ACHTUNG:CAUTION:
Never attempt to pry out piston seals and
dust seals.
WARNING
Replace the piston seals and dust seals
whenever a caliper is disassembled.
ÅFront
ıRear
Å
ı
EC5A4000
INSPECTION
EC534112
Master cylinder
1. Inspect:
Master cylinder inner surface a
Wear/scratches → Replace master cyl-
inder assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
ÅFront
ıRear
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
ÅFront
ıRear
ı
Å
ı
Å
3. Inspect:
Master cylinder piston 1
Master cylinder cup 2
Wear/damage/score marks → Replace
master cylinder kit.
ÅFront
ıRear
Åı

5 - 17
CHAS
EC534214
Caliper
1. Inspect:
Caliper cylinder inner surface a
Wear/score marks → Replace caliper
assembly.
ÅFront
ıRear
ı Å
2. Inspect:
Caliper piston 1
Wear/score marks → Replace caliper
piston assembly.
WARNING
Replace the piston seals and dust seals 2
whenever a caliper is disassembled.
EC534301
Brake hose
1. Inspect:
Brake hose 1
Crack/damage → Replace.
EC5A5000
ASSEMBLY AND INSTALLATION
WARNING
All internal parts should be cleaned in
new brake fluid only.
Internal parts should be lubricated with
brake fluid when installed.
Replace the piston seals and dust seals
whenever a caliper is disassembled.
EC5A5800
Caliper piston
1. Clean:
Caliper
Piston seal
Dust seal
Caliper piston
Clean them with brake fluid.
FRONT BRAKE AND REAR BRAKE