crankcase YAMAHA YZ125LC 2005 Owner's Manual

4-52
ENGCDI MAGNETO
Extent of removal Order Part name Q’ty Remarks
CDI MAGNETO REMOVAL
Preparation for Seat and fuel tank Refer to “SEAT, FUEL TANK AND
removal SIDE COVERS” section.
Bolt [Radiator (left)] Refer to “RADIATOR” section.
Disconnect the CDI magneto lead.
1 Crankcase cover (left) 1
2 Nut (rotor) 1 Use special tool.
3 Rotor 1 Refer to “REMOVAL POINTS”.
4 Stator 1
5 Woodruff key 1
EC4L0000
CDI MAGNETO
1
Extent of removal:1CDI magneto removal



7 Nm (0.7 m•kg, 5.1 ft•lb)
56 Nm (5.6 m•kg, 40 ft•lb)
5 Nm (0.5 m•kg, 3.6 ft•lb)
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4-55
ENGCDI MAGNETO
7. Connect:
9CDI magneto lead 1
Refer to “CABLE ROUTING DIAGRAM”
section in the CHAPTER 2.
8. Install:
9Gasket [crankcase cover (left)]
9Crankcase cover (left) 1
9Screw [crankcase cover (left)] 2
NOTE:
Tighten the screws in stage, using a crisscross
pattern.
5 Nm (0.5 m•kg, 3.6 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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4-62
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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4-63
ENGCRANKCASE AND CRANKSHAFT
EC4N3302
Crankshaft
1. Remove:
9Crankshaft 1
Use the crankcase separating tool 2.
NOTE:
Make appropriate bolts 3as shown available by
yourself and attach the tool with them.
cC
Do not use a hammer to drive out the
crankshaft.
EC4N3401
Crankshaft bearing
1. Remove:
9Bearing 1
NOTE:
9Remove the bearing from the crankcase by
pressing its inner race as shown in å.
9If the bearing is removed together with the
crankshaft, remove the bearing using a general
bearing puller 2as shown in ∫.
9Do not use the removed bearing.
EC4N4000
INSPECTION
EC4N4101
Crankcase
1. Inspect:
9Contacting surface a
Scratches Replace.
9Engine mounting boss b, crankcase
Cracks/Damage Replace.
Crankcase separating tool:
YU-1135-A/90890-01135
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4-64
ENGCRANKCASE AND CRANKSHAFT
Standard
Runout 0.03 mm 0.05 mm
limit: (0.0012 in) (0.0020 in)
Small end 0.8~1.0 mm 2.0 mm
free play: (0.031~0.039 in) (0.08 in)
Side 0.06~0.64 mm
—
clearance: (0.002~0.025 in)
Crank 55.90~55.95 mm
—
width: (2.201~2.203 in)
2. Inspect:
9Bearings 1
Rotate inner race with a finger.
Rough spot/Seizure Replace.
3. Inspect:
9Oil seal 1
Damage Replace.
EC4N4202
Crankshaft
1. Measure:
9Runout limit a
9Small end free play limit b
9Connecting rod big end side clearance c
9Crank width d
Out of specification Replace.
Use the dial gauge and a thickness gauge.
EC4N5000
ASSEMBLY AND INSTALLATION
EC4N5300
Crankshaft bearing
1. Install:
9Bearing 1
To crankcase (left and right).
NOTE:
Install the bearing by pressing its outer race
parallel.
Dial gauge:
YU-3097/90890-01252
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4-65
ENGCRANKCASE AND CRANKSHAFT
EC4N5102
Oil seal
1. Install:
9Oil seal (left) 1
9Oil seal (right) 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 outward.
EC4N5272
Crankshaft
1. Install:
9Crankshaft 1
Use the crankshaft installing tool 2, 3, 4
åFor USA and CDN
∫Except for USA and CDN
NOTE:
9Hold the connecting rod at top dead center with
one hand while turning the nut of the installing
tool with the other. Operate the installing tool
until the crankshaft bottoms against the bear-
ing.
9Before installing the crankshaft, clean the con-
tacting surface of crankcase.
9Apply the lithium soap base grease on the oil
seal lip.
cC
Do not use a hammer to drive in the crank-
shaft.
Crankshaft installing tool:
Pot 2 2
:
YU-90050/90890-01274
Bolt 3 3
:YU-90050/90890-01275
Adapter 4 4
:YU-90063/90890-01278
å∫
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ENGCRANKCASE AND CRANKSHAFT
2. Check:
9Shifter operation
9Transmission operation
Unsmooth operation Repair.
3. Apply:
9Sealant
On the crankcase (right) 1
NOTE:
Clean the contacting surface of crankcase (left
and right) before applying the sealant.
Quick gasket®:
ACC-QUICK-GS-KT
Yamaha bond No. 1215:
90890-85505
4. Install:
9Dowel pin 1
9O-ring 2
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7. Install:
9Holder 1
9Bolt (holder) 2
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ENGCRANKCASE AND CRANKSHAFT
6. Install:
9Clamp 1
9Bolt (crankcase) 2
NOTE:
Tighten the crankcase tightening bolts in stage,
using a crisscross pattern.
14 Nm (1.4 m•kg, 10 ft•lb)
5. Install:
9Crankcase (right) 1
Use the crankshaft installing tool 2, 3, 4.
ÅFor USA and CDN
ıExcept for USA and CDN
NOTE:
9Use two plain washers (Yamaha genuine:
90201-243K3) 5or the ones of a size as
shown one on the other. (Except for USA and
CDN)
9Install so that the plain washers do not deviate
from the crankshaft center. (Except for USA
and CDN)
9When installing the crankcase, the connecting
rod should be positioned at TDC (top dead
center).
9Install while checking that the dowel pin is in
place.
Crankshaft installing tool:
Pot 2:
YU-90050/90890-01274
Bolt 3:YU-90050/90890-01275
Adapter 4:YM-01499/90890-01499
10 Nm (1.0 m•kg, 7.2 ft•lb)
å∫
∫
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8. Install:
9Segment 1
9Bolt (segment) 2
NOTE:
9When installing the segment onto the shift cam
3, align the punch mark awith the dowel pin
b.
9Turn the segment clockwise until it stops and
tighten the bolt.
9. Remove:
9Sealant
Forced out on the cylinder mating surface.
10. Apply:
9Engine oil
To the crank pin, bearing, oil delivery hole
and connecting rod big end washer.
11. Check:
9Crankshaft and transmission operation
Unsmooth operation Repair.
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ENGCRANKCASE AND CRANKSHAFT
30 Nm (3.0 m•kg, 22 ft•lb)
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