crankcase YAMAHA YZ125LC 2005 User Guide

4-27
ENGCYLINDER HEAD, CYLINDER AND PISTON
EC475280
Piston ring and piston
1. Install:
9Piston ring 1
NOTE:
9Take care not to scratch the piston or damage
the piston ring.
9Align the piston ring gap with the pin 2.
9After installing the piston ring, check the
smooth movement of it.
2. Install:
9Gasket (cylinder) 1
9Small end bearing 2
9Dowel pin 3
NOTE:
9Apply the engine oil onto the bearing (crank-
shaft and connecting rod) and connecting rod
big end washers.
9Install the gasket with the seal print side toward
the crankcase.
3. Install:
9Piston 1
9Piston pin 2
9Piston pin clip 3
NOTE:
9The arrow aon the piston dome must point to
exhaust side.
9Before installing the piston pin clip, cover the
crankcase with a clean rag to prevent the pis-
ton pin clip from falling into the crankcase cavi-
ty.
cC
9When installing the piston pin clip, use
the hand so that it may not be distorted.
9Do not allow the clip open ends to meet
the piston pin slot b.
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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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4-39
ENG
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE
GEAR
EC4C3000
REMOVAL POINTS
EC483111
Primary drive gear
1. Loosen:
9Bolt (primary drive gear) 1
NOTE:
Place an aluminum plate abetween the teeth of
the primary drive gear 2and driven gear 3.
EC4B3101
Kick axle assembly
1. Remove:
9Kick axle assembly 1
NOTE:
Unhook the torsion spring 2from the hole ain
the crankcase.
EC4C3101
Shift guide and shift lever assembly
1. Remove:
9Bolt (shift guide)
9Shift guide 1
9Shift lever assembly 2
NOTE:
The shift lever assembly is disassembled at the
same time as the shift guide.
EC4C4000
INSPECTION
EC4B4100
Kick axle and kick gear
1. Check:
9Kick gear smooth movement
Unsmooth movement Replace.
2. Inspect:
9Kick axle 1
Wear/Damage Replace.
EC4B4200
Kick gear and kick idle gear
1. Inspect:
9Kick gear 1
9Kick idle gear 2
9Gear teeth a
Wear/Damage Replace.
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4-42
ENG
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE
GEAR
4. Install:
9Bolt (shift guide) 1
EC4C5301
Shift shaft
1. Install:
9Roller 1
9Shift shaft 2
NOTE:
Apply the transmission oil on the roller and shift
shaft.
EC4B5302
Kick axle assembly
1. Install:
9Kick gear 1
9Plain washer 2
9Torsion spring 3
To kick axle 4.
NOTE:
Make sure the stopper aof the torsion spring
fits into the hole bon the kick axle.
2. Install:
9Spring guide 1
NOTE:
Slide the spring guide into the kick axle, make
sure the groove ain the spring guide fits on the
stopper of the torsion spring.
3. Install:
9Kick axle assembly 1
NOTE:
9Apply the transmission oil on the kick axle.
9Slide the kick axle assembly into the
crankcase, make sure the clip 2and kick axle
stopper afit into their home positions b, c.
10 Nm (1.0 m•kg, 7.2 ft•lb)
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4-43
ENG
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE
GEAR
4. Hook:
9Torsion spring 1
NOTE:
Turn the torsion spring clockwise and hook into
the proper hole ain the crankcase.
EC4C5402
Kick idle gear
1. Install:
9Kick idle gear 1
9Plain washer 2
9Circlip 3
NOTE:
Apply the transmission oil on the kick idle gear
inner circumference.
EC4C5503
Primary drive gear
1. Install:
9Spacer 1
9Primary drive gear 2
9Bolt 3
NOTE:
Install the primary drive gear with its depressed
side toward you.
2. Install:
9Primary driven gear
Refer to “CLUTCH AND PRIMARY DRI-
VEN GEAR” section.
3. Tighten:
9Bolt (primary drive gear) 1
NOTE:
Place an aluminum plate abetween the teeth of
the primary drive gear 2and driven gear 3.
4. Install:
9Dowel pin 1
9Gasket [crankcase cover (right)] 2
48 Nm (4.8 m•kg, 35 ft•lb)
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4-44
ENG
KICK AXLE, SHIFT SHAFT AND PRIMARY DRIVE
GEAR
5. Install:
9Crankcase cover (right) 1
NOTE:
Mesh the governor gear 2, and impeller shaft
gear 3with primary drive gear 4.
6. Install:
9Bolt [crankcase cover (right)] 1
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
7. Install:
9Kick starter 1
9Plain washer 2
9Bolt (kick starter) 3
NOTE:
Install the kick starter closest to but not contact-
ing the pillar tube 4.
8. Install:
9Shift pedal 1
9Bolt (shift pedal) 2
NOTE:
Align the upper line aof the shift pedal with the
center bof the crankcase projection and rotate
the shift pedal counterclockwise until it first
engages. Then install the shift pedal.
12 Nm (1.2 m•kg, 8.7 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
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4-45
ENGYPVS GOVERNOR
Extent of removal Order Part name Q’ty Remarks
YPVS GOVERNOR REMOVAL
Preparation for Crankcase cover (right)
Refer to “KICK AXLE, SHIFT SHAFT AND
removalPRIMARY DRIVE GEAR” section.
1 Governor assembly 1
2 Dowel pin 1 Refer to “REMOVAL POINTS”.
3 Retainer 1
4 Ball 4
5 Retainer weight 1
6 Plain washer 4
7 Thrust bearing 2
8 Collar 1
9 Plate 1
10 Compression spring 1
11 Governor gear 1
12 Governor shaft 1
EC4K0000
YPVS GOVERNOR
1
Extent of removal:1YPVS governor removal and disassembly
5 Nm (0.5 m•kg, 3.6 ft•lb)
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4-47
ENGYPVS GOVERNOR
2. Install:
9Ball 1
9Retainer 2
To governor shaft 3.
NOTE:
Apply the transmission oil on the retainer and
ball.
3. Install:
9Dowel pin 1
NOTE:
9While compressing the spring, install the dowel
pin.
9Make sure the dowel pin fits into the groove a
in the retainer.
4. Install:
9Governor assembly 1
NOTE:
Align the groove ain the governor with the fork
band set the governor in the crankcase cover.
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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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4-50
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.
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