2004 YAMAHA YZ250F water pump

CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS
................................. 4-1
EXHAUST PIPE AND SILENCER
............ 4-3
RADIATOR
................................................ 4-5
CARBURETOR
......................................... 4-8
CAMSHAFTS
.......................................... 4-21
CYLINDER HEAD
................................... 4-30
VALVES AND VALVE SPRINGS
........... 4-33
CYLINDER AND PISTON
....................... 4-42
CLUTCH
.................................................. 4-49
OIL FILTER ELEMENT, WATER PUMP
AND RIGHT CRANKCASE COVER
....... 4-56
BALANCER
............................................ 4-63
OIL PUMP
............................................... 4-66
KICK SHAFT AND SHIFT SHAFT
.......... 4-71
CDI MAGNETO
....................................... 4-78
ENGINE REMOVAL
................................ 4-82
CRANKCASE AND CRANKSHAFT
....... 4-87
TRANSMISSION, SHIFT CAM
AND SHIFT FORK
.................................. 4-96
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
...... 5-1
FRONT BRAKE AND REAR BRAKE
..... 5-10
FRONT FORK
......................................... 5-26
HANDLEBAR
.......................................... 5-39
STEERING
.............................................. 5-45
SWINGARM
............................................ 5-50
REAR SHOCK ABSORBER
................... 5-58

1 - 3
GEN
INFO

IMPORTANT INFORMATION
EC130000
IMPORTANT INFORMATION
EC131010
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Remove all dirt, mud, dust, and foreign
material before removal and disassem-
bly.
When washing the machine with high
pressured water, cover the parts follows.

Silencer exhaust port

Side cover air intake port

Water pump housing hole at the bottom

Drain hole on the cylinder head (right
side)
2. Use proper tools and cleaning equip-
ment. Refer to “SPECIAL TOOLS” sec-
tion.
3. When disassembling the machine, keep
mated parts together. They include
gears, cylinders, pistons, and other
mated parts that have been “mated”
through normal wear. Mated parts must
be reused as an assembly or replaced.
4. During the machine disassembly, clean
all parts and place them in trays in the
order of disassembly. This will speed up
assembly time and help assure that all
parts are correctly reinstalled.
5. Keep away from fire.

SPEC

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)
Cooling:
Radiator core size
Width 107.8 mm (4.2 in) ----
Height 220 mm (8.7 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure110 kPa (1.1 kg/cm
2

, 15.6 psi)----
Radiator capacity (total) 0.56 L (0.49 Imp qt, 0.59 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit

SPEC

2 - 10
MAINTENANCE SPECIFICATIONS
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) M6
×
1.0 2 7 0.7 5.1
(stud bolt) M8
×
1.25 1 15 1.5 11
(bolt) M9
×
1.25 4 38 3.8 27
(nut) 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
Balancer weight M6
×
1.0 2 10 1.0 7.2
Balancer shaft driven gear M14
×
1.0 1 50 5.0 36
Timing chain guide (intake side) M6
×
1.0 2 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
Impeller M8
×
1.25 1 14 1.4 10
Radiator hose clamp M6
×
1.0 8 2 0.2 1.4
Coolant drain bolt M6
×
1.0 1 10 1.0 7.2
Water pump housing M6
×
1.0 4 10 1.0 7.2
Radiator M6
×
1.0 6 10 1.0 7.2
Radiator guard M6
×
1.0 2 10 1.0 7.2
Radiator pipe 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 3 10 1.0 7.2
Oil filter element drain bolt M6
×
1.0 1 10 1.0 7.2
Oil filter element cover M6
×
1.0 2 10 1.0 7.2
Oil strainer M6
×
1.0 2 10 1.0 7.2
Oil delivery pipe 1 (M10) M10
×
1.25 1 20 2.0 14
(M8) M8
×
1.25 2 18 1.8 13
Oil hose M6
×
1.0 2 8 0.8 5.8
Oil hose clamp—2 2 0.2 1.4
Oil strainer and frame M14
×
1.5 1 70 7.0 50
Carburetor joint clamp M4
×
0.7 2 3 0.3 2.2
Air filter joint clamp M6
×
1.0 1 3 0.3 2.2
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
Air filter case M6
×
1.0 2 8 0.8 5.8
Air filter joint and air filter case M5
×
0.8 1 4 0.4 2.9
Air filter element M6
×
1.0 1 2 0.2 1.4
Exhaust pipe (nut) M8
×
1.25 1 13 1.3 9.4
(bolt) M8
×
1.25 1 24 2.4 17
Exhaust pipe protector M6
×
1.0 3 10 1.0 7.2

4 - 56
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Extent of removal:1 Oil filter element removal2 Water pump removal
3 Right crankcase cover removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER ELEMENT, WATER
PUMP AND RIGHT CRANK-
CASE COVER 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.
Radiator hose 3 Disconnect at water pump side.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section.
Brake pedal Refer to “ENGINE REMOVAL” section.
Right engine guard
1 Oil filter element cover 1
2 Oil filter element 1
13

4 - 57
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Extent of removal Order Part name Q’ty Remarks
3 Water pump housing 1
4 Oil delivery pipe 1
5 Bolt (oil hose) 1
6 Kickstarter crank 1
7 Right crankcase cover 1
8 Impeller 1
Refer to “REMOVAL POINTS”. 9 Washer 1
10 Impeller shaft 1
11 Oil seal 2
12Bearing
1
3
2

4 - 58
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
REMOVAL POINTS
Impeller shaft
1. Remove:
Impeller 1
Washer 2
Impeller shaft 3
NOTE:
Hold the impeller shaft on its width across the
flats a with spanners, etc. and remove the
impeller.
EC4G3210
Oil seal
NOTE:
It is not necessary to disassemble the water
pump, unless there is an abnormality such as
excessive change in coolant level, discolora-
tion of coolant, or milky transmission oil.
1. Remove:
Bearing 1
2. Remove:
Oil seal 1
INSPECTION
Oil delivery pipe
1. Inspect:
Oil delivery pipe 1
Bend/damage → Replace.
Clogged → Blow.

4 - 59
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
EC444200
Impeller shaft
1. Inspect:
Impeller shaft 1
Bend/wear/damage → Replace.
Fur deposits → Clean.
EC444300
Impeller shaft gear
1. Inspect:
Gear teeth a
Wear/damage → Replace.
EC4H4600
Bearing
1. Inspect:
Bearing
Rotate inner race with a finger.
Rough spot/seizure → Replace.
EC444400
Oil seal
1. Inspect:
Oil seal 1
Wear/damage → Replace.
ASSEMBLY AND INSTALLATION
Oil seal
1. Install:
Oil seal 1
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
Install the oil seal with its manufacture’s
marks or numbers facing the right crankcase
cover 2.