2005 YAMAHA YZ125LC water pump

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND SIDE
COVERS.....................................................4-1
EXHAUST PIPE AND SILENCER..............4-3
RADIATOR..................................................4-4
CARBURETOR AND REED VALVE...........4-7
CYLINDER HEAD , CYLINDER AND
PISTON.....................................................4-17
CLUTCH AND PRIMARY DRIVEN
GEAR.......................................................4-30
KICK AXLE, SHIFT SHAFT AND
PRIMARY DRIVE GEAR...........................4-37
YPVS GOVERNOR...................................4-45
WATER PUMP..........................................4-48
CDI MAGNETO.........................................4-52
ENGINE REMOVAL..................................4-56
CRANKCASE AND CRANKSHAFT.........4-61
TRANSMISSION, SHIFT CAM AND
SHIFT FORK.............................................4-69
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL........5-1
FRONT BRAKE AND REAR BRAKE.......5-10
FRONT FORK...........................................5-26
HANDLEBAR............................................5-41
STEERING................................................5-48
SWINGARM..............................................5-53
REAR SHOCK ABSORBER.....................5-61
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1-3
GEN
INFO
IMPORTANT INFORMATION
EC130000
IMPORTANT INFORMATION
EC131010
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Remove all dirt, mud, dust, and foreign ma-
terial before removal and disassembly.
When washing the machine with high pres-
sured water, cover the parts as follows.
9Silencer exhaust port
9Side cover air intake port
9Crankcase cover hole at the bottom
9Water pump housing hole at the bottom
9End of each hose
2. Use proper tools and cleaning equipment.
Refer to “SPECIAL TOOLS” section.
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 as-
sembly 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 cor-
rectly reinstalled.
5. Keep away from fire.
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2-4
SPECMAINTENANCE SPECIFICATIONS
Item Standard Limit
Transmission:
Main axle deflection limit…
0.01 mm (0.0004 in)
Drive axle deflection limit…
0.01 mm (0.0004 in)
Shifter:
Shifting type Cam drum and guide bar…
Guide bar bending limit…
0.05 mm (0.0020 in)
Kick starter type: Kick and mesh type…
Kick clip friction force P=0.8~1.2 kg (1.8~2.6 lb)…
Air filter oil grade (oiled filter):Foam-air-filter oil or equivalent oil…
Carburetor: USA, CDN, ZA
EUROPE
AUS, NZ
Type/Manufacturer TMXχ
38SS←
/MIKUNI
I.D. mark 1C31 00 1C32 10…
Main jet (M.J.) #410 #430…
Jet needle-clip position (J.N.) 6CHY5-80-4←…
Cutaway (C.A.) 4.0←…
Pilot jet (P.J.) #40←…
Pilot air screw (P.A.S.) 2-1/4←…
Valve seat size (V.S.)
ø3.8 mm (0.15 in)←…
Starter jet (G.S.) #80←…
Fuel level (F.L.) 9.5~10.5 mm ←
(0.37~0.41 in)
Reed valve:
Thickness* 0.47 mm (0.019 in)…
Valve stopper height 8.2~8.6 mm (0.323~0.339 in)…
Valve bending limit…
0.2 mm (0.008 in)
Cooling:
Radiator core size:
Width 107.8 mm (4.24 in)…
Height (left) 240 mm (9.45 in)…
(right) 220 mm (8.66 in)…
Thickness 32 mm (1.26 in)…
Radiator cap opening pressure 95~125 kPa…
(0.95~1.25 kg/cm
2, 13.5~17.8 psi)
Radiator capacity (total) 0.56 L (0.49 Imp qt, 0.59 US qt)…
Water pump:
Type Single-suction centrifugal pump…
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2-5
SPECMAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q'tyT ightening torqueNm m•kg ft•lb
Spark plug
M14S×1.25 1 20 2.0 14
Cylinder head (nut) M 8 ×1.25 5 28 2.8 20
(stud) M 8 ×1.25 5 13 1.3 9.4
Cylinder (nut) M 8 ×1.25 4 30 3.0 22
(stud) M10 ×1.25 4 13 1.3 9.4
Power valve:
Cover M 5 ×0.8 4 5 0.5 3.6
Link lever M 4 ×0.7 1 4 0.4 2.9
Holder (power valve) M 5 ×0.8 4 8 0.8 5.8
Push rod M 5 ×0.8 1 5 0.5 3.6
Thrust plate M 5 ×0.8 1 4 0.4 2.9
Governor fork M 4 ×0.7 2 5 0.5 3.6
Housing M 5 ×0.8 3 4 0.4 2.9
Water pump housing cover M 6 ×1.0 4 10 1.0 7.2
Coolant drain bolt M 6 ×1.0 1 10 1.0 7.2
Radiator M 6 ×1.0 6 10 1.0 7.2
Radiator panel M 6 ×1.0 2 10 1.0 7.2
Radiator hose clamp M 6 ×1.0 8 1 0.1 0.7
Air filter element M 6 ×1.0 1 2 0.2 1.4
Carburetor joint M 6 ×1.0 4 10 1.0 7.2
Carburetor joint clamp M 4 ×0.7 1 2 0.2 1.4
Air filter joint clamp M 4 ×0.7 1 2 0.2 1.4
Air filter case M 6 ×1.0 4 8 0.8 5.8
Air filter guide clamp M 5 ×0.8 1 4 0.4 2.9
Read valve M 3 ×0.5 6 1 0.1 0.7
Throttle cable adjust bolt and locknut M 8 ×1.25 1 7 0.7 5.1
Throttle cable M 6 ×0.75 1 4 0.4 2.9
Crankcase M 6 ×1.0 12 14 1.4 10
Crankcase cover (right) M 6 ×1.0 8 10 1.0 7.2
Crankcase cover (left) M 6 ×1.0 4 5 0.5 3.6
Chain cover M 6 ×1.0 2 5 0.5 3.6
Bearing plate cover M 6 ×1.0 4 10 1.0 7.2
Holder M 6 ×1.0 1 10 1.0 7.2
Oil check bolt M 6 ×1.0 1 10 1.0 7.2
Oil drain bolt M10 ×1.25 1 20 2.0 14
Kick starter M 6 ×1.0 1 10 1.0 7.2
Cluch cover M 6 ×1.0 6 10 1.0 7.2
Primary drive gear M 8 ×1.25 1 48 4.8 35
Clutch boss M16 ×1.0 1 80 8.0 58
Clutch spring M 6 ×1.0 5 10 1.0 7.2
Clutch cable adjust bolt and locknut M 6 ×0.75 1 4 0.4 2.9
Drive sprocket M18 ×1.0 1 75 7.5 54
Shift pedal M 6 ×1.0 1 12 1.2 8.7
Bearing plate cover (shift cam) M 6 ×1.0 2 10 1.0 7.2
Shift guide M 6 ×1.0 2 10 1.0 7.2
Stopper lever M 6 ×1.0 1 10 1.0 7.2
Segment M 8 ×1.25 1 30 3.0 22
 
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4-37
ENG
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE
GEAR
Extent of removal Order Part name Q’ty Remarks
RPIMARY DRIVE GEAR REMOVAL
Preparation for Drain the transmission oil.Refer to “TRANSMISSION OIL REPLACE-
removalMENT“ section in the CHAPTER 3.
Clutch cable Disconnect at engine side.
Bolt (brake pedal) Shift the brake pedal downward.
Radiator hose 4 Disconnect at water pump side.
Bolt (push rod)
Refer to “CYLINDER HEAD, CYLINDER
AND PISTON” section.
1 Kick starter 1
2 Crankcase cover (right) 1
3 Bolt (Primary drive gear) 1 Only loosening
Refer to “REMOVAL POINTS”.
4 Primary driven gear 1 Refer to “CLUTCH AND PRIMARY
DRIVEN GEAR”section.
5 Primary drive gear 1
EC4C0000
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE GEAREC4C8000PRIMARY DRIVE GEAR
1
Extent of removal:1Primary drive gear removal
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
48 Nm (4.8 m•kg, 35 ft•lb)
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4-48
ENGWATER PUMP
Extent of removal Order Part name Q’ty Remarks
WATER PUMP DISASSEMBLY
Preparation for Crankcase cover (right)
Refer to “KICK AXLE, SHIFT SHAFT AND
removalPRIMARY DRIVE GEAR” section.
1 Water pump housing cover 1
2 Impeller shaft gear 1
3 Dowel pin 1Refer to “REMOVAL POINTS”.
4 Plain washer 1
5 Impeller shaft assembly 1
6 Bearing 1
Refer to “REMOVAL POINTS”.
7 Oil seal 2
EC4G0000
WATER PUMP
1
2
Extent of removal:1Impeller shaft removal2Oil seal removal








10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
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4-49
ENGWATER PUMP
EC4G3000
REMOVAL POINTS
EC4G3210
Oil seal
NOTE:
9Replace the oil seal when transmission oil or
coolant leaks out from the water pump housing
hole at the bottom.
9Do not reuse the removed bearing and oil seal.
1. Remove:
9Bearing 1
2. Remove:
9Oil seal (outside) 1
9Oil seal (inside) 2
EC4G4000
INSPECTIONEC444200
Impeller shaft assembly
1. Inspect:
9Impeller shaft assembly1
Bend/Wear/Damage Replace.
Fur deposits Clean.
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4-50
ENGWATER PUMP
EC444300
Impeller shaft gear
1. Inspect:
9Gear teeth a
Wear/Damage Replace.
EC4H4600
Bearing
1. Inspect:
9Bearing 1
Rotate inner race with a finger.
Rough spot/Seizure Replace.
EC444400
Oil seal
1. Inspect:
9Oil seal 1
Wear/Damage Replace.
EC4G5000
ASSEMBLY AND INSTALLATION
EC4G5111
Oil seal
1. Install:
9Oil seal (inside) 1
9Oil seal (outside) 2
NOTE:
9Apply the lithium soap base grease on the oil
seal lip.
9Install the oil seal with its manufacture's marks or
numbers facing the crankcase cover (right) 3.
2. Install:
9Bearing 1
NOTE:
Install the bearing by pressing its outer race par-
allel.
1C3-9-30-4C 25/5/04 7:17 PM Page 28