2005 YAMAHA YZ125LC engine

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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4-56
ENGENGINE REMOVAL
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Seat and fuel tankRefer to “SEAT, FUEL TANK AND
SIDE COVERS” section.
Carburetor Refer to “CARBURETOR AND REED
VALVE” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Clutch cable Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Spark plug cap
Disconnect the CDI magneto lead.
EC4M0000
ENGINE REMOVAL
w
Support the machine securely so there is no dan-
ger of it falling over.
26 Nm (2.6 m•kg, 19 ft•lb)
34 Nm (3.4 m•kg, 24 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
85 Nm (8.5 m•kg, 61 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
5 Nm (0.5 m•kg, 3.6 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
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4-57
ENGENGINE REMOVAL
Extent of removal:1Engine removal
Extent of removal Order Part name Q’ty Remarks
1 Chain cover 1
2 Nut (drive sprocket) 1
3 Lock washer 1 Refer to “REMOVAL POINTS”.
4 Drive sprocket 1
5 Clip 1
6 Bolt (brake pedal) 1
7 Brake pedal 1
8 Engine bracket 2
9 Engine mounting bolt 3
10 Pivot shaft 1
Refer to “REMOVAL POINTS”.
11 Engine 1
1







26 Nm (2.6 m•kg, 19 ft•lb)
34 Nm (3.4 m•kg, 24 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
85 Nm (8.5 m•kg, 61 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
5 Nm (0.5 m•kg, 3.6 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
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4-58
ENGENGINE REMOVAL
EC4M3000
REMOVAL POINTS
EC4F3100
Drive sprocket
1. Remove:
9Nut (drive sprocket) 1
9Lock washer 2
NOTE:
9Straighten the lock washer tab.
9Loosen the nut while applying the rear brake.
2. Remove:
9Drive sprocket 1
9Drive chain 2
NOTE:
Remove the drive sprocket together with the dri-
ve chain.
EC4M3301
Engine removal
1. Remove:
9Pivot shaft 1
NOTE:
If the pivot shaft is pulled all the way out, the
swingarm will come loose. If possible, insert a
shaft of similar diameter into the other side of
the swingarm to support it.
2. Remove:
9Engine 1
From right side.
NOTE:
Make sure that the couplers, hoses and cables
are disconnected.
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4-59
ENGENGINE REMOVAL
EC4M5000
ASSEMBLY AND INSTALLATION
EC4M5171
Engine installation
1. Install:
9Engine 1
Install the engine from right side.
9Pivot shaft 2
9Engine mounting bolt (lower) 3
9Engine mounting bolt (front) 4
9Engine bracket 5
9Bolt (engine bracket) 6
9Engine mounting bolt (upper) 7
NOTE:
Apply the molybdenum disulfide grease on the
pivot shaft.
EC4M5211
Brake pedal
1. Install:
9Spring 1
9Brake pedal 2
9O-ring 3
9Bolt (brake pedal) 4
9Clip 5
NOTE:
Apply the lithium soap base grease on the bolt,
O-rings and brake pedal bracket.
EC4M5311
Drive sprocket
1. Install:
9Drive sprocket 1
9Drive chain 2
NOTE:
Install the drive sprocket together with the drive
chain.
85 Nm (8.5 m•kg, 61 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
64 Nm (6.4 m•kg, 46 ft•lb)
34 Nm (3.4 m•kg, 24 ft•lb)
34 Nm (3.4 m•kg, 24 ft•lb)
26 Nm (2.6 m•kg, 19 ft•lb)
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4-60
ENGENGINE REMOVAL
2. Install:
9Lock washer 1
9Nut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
3. Bend the lock washer tab to lock the nut.
4. Install:
9Chain guide 1
9Chain cover 2
9Screw (chain cover) 3
5 Nm (0.5 m•kg, 3.6 ft•lb)
75 Nm (7.5 m•kg, 54 ft•lb)
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4-61
ENGCRANKCASE AND CRANKSHAFT
Extent of removal Order Part name Q’ty Remarks
CRANKCASE AND CRANKSHAFT
REMOVAL
Preparation for Engine Refer to “ENGINE REMOVAL”section.
removal Piston Refer to “
CYLINDER HEAD, CYLINDER
AND PISTON
” section.
Primary drive gear
Kick idle gearRefer to “
KICK AXLE, SHIFT SHAFT AND
Stopper leverPRIMARY DRIVE GEAR”section.
Rotor and stator Refer to “CDI MAGNETO” section.
1 Segment 1 Refer to “REMOVAL POINTS”.
2 Bolt [L=45 mm (1.77 in)] 6
3 Bolt [L=55 mm (2.17 in)] 4
4 Bolt [L=65 mm (2.56 in)] 1
5 Bolt [L=75 mm (2.95 in)] 1
6 Holder 1
7 Crankcase (right) 1 Use special tool.
8 Crankcase (left) 1 Refer to “REMOVAL POINTS”.
9 Crankshaft 1 Use special tool.
Refer to “REMOVAL POINTS”.
10 Oil seal 2
11 Bearing 2 Refer to “REMOVAL POINTS”.





EC4N0000
CRANKCASE AND CRANKSHAFT
12
3
Extent of removal:1Crankcase separation2Crankshaft removal
3Crankshaft bearing removal



30 Nm (3.0 m•kg, 22 ft•lb)10 Nm (1.0 m•kg, 7.2 ft•lb)
20 Nm (2.0 m•kg, 14 ft•lb)
14 Nm (1.4 m•kg, 10 ft•lb)
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ENGCRANKCASE AND CRANKSHAFT
EC4N3000
REMOVAL POINTS
EC4N3212
Crankcase
1. Remove:
9Crankcase (right) 1
Use the crankcase separating tool 2.
NOTE:
9Make appropriate bolts 3as shown available
by yourself and attach the tool with them.
9Fully tighten the tool holding bolts, but make
sure the tool body is parallel with the case. If
necessary, one screw may be backed out
slightly to level tool body.
9As pressure is applied, alternately tap on the
front engine mounting boss and transmission
shafts.
cC
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If one end “hangs
up”, take pressure off the push screw, re-
align, and start over. If the cases do not
separate, check for a remaining case
screw or fitting. Do not force.
Rotor puller:
YU-1362-A/90890-01362
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