Fork YAMAHA YZ125LC 2004 Owner's Manual

4-70
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H3000
REMOVAL POINTS
EC4H3200
Transmission
1. Remove:
9Main axle 1
9Drive axle 2
NOTE:
9Tap lightly on the transmission drive axle with a
soft hammer to remove.
9Remove assembly carefully. Note the position
of each part. Pay particular attention to the lo-
cation and direction of shift forks.
EC4H4000
INSPECTION
EC4H4200
Gears
1. Inspect:
9Matching dog a
9Gear teeth b
9Shift fork groove c
Wear/Damage Replace.
2. Check:
9Gears movement
Unsmooth movement 
Repair or replace.
EC4H4600
Bearing
1. Inspect:
9Bearing 1
Rotate inner race with a finger.
Rough spot/Seizure Replace.
5XE-9-30-4D 3/24/03 11:14 PM Page 28

4-71
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H4801
Shift fork, shift cam and segment
1. Inspect:
9Shift fork 1
Wear/Damage/Scratches Replace.
2. Inspect:
9Shift cam 1
9Segment 2
9Guide bar 3
Bend/Wear/Damage Replace.
3. Check:
9Shift fork movement
On its guide bar.
Unsmooth operation Replace shift fork
and/or guide bar.
NOTE:
For a malfunctioning shift fork, replace not only
the shift fork itself but the two gears each adja-
cent to the shift fork.
EC4H5000
ASSEMBLY AND INSTALLATION
EC4H5213
Transmission
1. Install:
95th pinion gear (23T) 1
93rd pinion gear (19T) 2
94th pinion gear (19T) 3
92nd pinion gear (15T) 4
To main axle 5.
NOTE:
9Apply the molybdenum disulfide oil on the 4th
and 5th pinion gears inner circumference and
on the end surface.
9Apply the molybdenum disulfide oil on the 2nd
and 3rd pinion gears inner circumference.
5XE-9-30-4D 3/24/03 11:14 PM Page 30

4-72
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
2. Install:
93rd wheel gear (29T) 1
94th wheel gear (24T) 2
92nd wheel gear (28T) 3
95th wheel gear (25T) 4
91st wheel gear (30T) 5
To drive axle 6.
NOTE:
9Apply the molybdenum disulfide oil on the 1st,
2nd and 3rd wheel gears inner circumference
and on the end surface.
9Apply the molybdenum disulfide oil on the 4th
and 5th wheel gears inner circumference.
3. Install:
9Plain washer 1
9Circlip 2
NOTE:
9Be sure the circlip sharp-edged corner ais po-
sitioned opposite side to the plain washer and
gear b.
9Be sure the circlip end cis positioned at axle
spline groove d.
4. Install:
9Spacer 1
NOTE:
9Apply the lithium soap base grease on the oil
seal lip.
9When installing the spacer into the crankcase,
pay careful attention to the crankcase oil seal
lip.
5XE-9-30-4D 3/24/03 11:14 PM Page 32

4-73
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H5312
Shift cam and shift fork
1. Install:
9Shift fork 1 (L) 1
9Shift fork 2 (C) 2
9Shift fork 3 (R) 3
NOTE:
9Mesh the shift fork #1 (L) with the 4th wheel
gear 4and #3 (R) with the 5th wheel gear 6
on the drive axle.
9Mesh the shift fork #2 (C) with the 3rd pinion
gear 5on the main axle.
2. Install:
9Shift cam 1
NOTE:
9Apply the transmission oil on the shift cam.
9Install the shift cam while holding up the 4th
wheel gear 2and keeping the shift fork #1 3
moved in the direction of the arrow.
3. Install:
9Guide bar (short) 1
9Guide bar (long) 2
NOTE:
9Apply the transmission oil on the guide bars.
9Be sure the long bar is inserted into the shift
forks #1 and #3 and the short one into #2.
5. Install:
9Main axle 1
9Drive axle 2
NOTE:
Apply the transmission oil on the crankcase
bearings.
5XE-9-30-4D 3/24/03 11:14 PM Page 34

4-74
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
4. Check:
9Shifter operation
9Transmission operation
Unsmooth operation Repair.
5XE-9-30-4D 3/24/03 11:14 PM Page 36

5-6
CHASFRONT WHEEL AND REAR WHEEL
5. Install:
9Wheel axle 1
NOTE:
Apply the lithium soap base grease on the wheel
axle.
6. Install:
9Nut (wheel axle) 1
7. Tighten:
9Bolt (axle holder) 1
NOTE:
Before tightening the bolt, fit the wheel axle to
the axle holder by stroking the front fork several
times with the front brake applied.
8. Install:
9Brake hose 1
To brake hose holder 2.
NOTE:
Before tightening the bolt (brake hose holder),
align the top aof the brake hose neck with the
brake hose holder bottom b. Then pass the
brake hose in front of the axle boss cand fit it
into the hose groove dso that the brake hose
does not contact the nut (wheel axle).
105 Nm (10.5 m•kg, 75 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
5XE-9-30-5A 4/28/03 6:06 PM Page 12

5-18
CHASFRONT BRAKE AND REAR BRAKE
3. Install:
9Brake hose holder 1
9Caliper 2
9Bolt (caliper) 3
NOTE:
Fit the brake hose holder cut aover the projec-
tion bon the front fork and clamp the brake
hose.
4. Tighten:
9Pad pin 4
5. Install:
9Pad pin plug 5
EC5A5121
Rear caliper
1. Install:
9Pad support 1
9Brake pad 2
9Pad pin 3
NOTE:
9Install the brake pads with their projections
ainto the caliper recesses b.
9Temporarily tighten the pad pin at this point.
2. Install:
9Copper washer 1
9Union bolt 2
w
Always use new copper washers.
cC
Install the brake hose so that its pipe por-
tion a a
directs as shown and lightly touch-
es the projection b b
on the caliper.
30 Nm (3.0 m•kg, 22 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
18 Nm (1.8 m•kg, 13 ft•lb)
3 Nm (0.3 m•kg, 2.2 ft•lb)
5XE-9-30-5A 4/28/03 6:06 PM Page 36

5-26
CHASFRONT FORK
Extent of removal Order Part name Q’ty Remarks
FRONT FORK REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Front wheel Refer to “FRONT WHEEL AND
REAR WHEEL”section.
Front caliper Refer to “FRONT BRAKE AND
REAR BRAKE”section.
Number plate
1 Protector 1
2 Brake hose holder 2
3 Pinch bolt (handle crown) 2 Only loosening.
4 Cap bolt 1
Loosen when disassembling the front fork.
5 Pinch bolt (under bracket) 2 Only loosening.
6 Front fork 1
1
w
Support the machine securely so there is no dan-
ger of it falling over.
Extent of removal:1Front fork removal
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
20 Nm (2.0 m•kg, 14 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
EC550000
FRONT FORK
5XE-9-30-5B 4/30/03 9:41 AM Page 2

5-27
CHASFRONT FORK
Extent of removal Order Part name Q’ty Remarks
FRONT FORK DISASSEMBLY
1Cap bolt 1 Refer to “REMOVAL POINTS”.
2Fork spring 1 Drain the folk oil.
3Dust seal 1
4Stopper ring 1 Refer to “REMOVAL POINTS”.
5Inner tube 1
6Outer tube 1
7Piston metal 1
8Slide metal 1
9Oil seal washer 1
0Oil seal 1
qSpring guide 1
wBase valve 1 Use special tool.
eDamper rod 1 Refer to “REMOVAL POINTS”.
EC558000
FRONT FORK DISASSEMBLY
1
Extent of removal:1Oil seal removal2Damper rod removal
2






29 Nm (2.9 m•kg, 21 ft•lb)1 Nm (0.1 m•kg, 0.7 ft•lb)
30 Nm (3.0 m•kg, 22 ft•lb)
55 Nm (5.5 m•kg, 40 ft•lb)
5XE-9-30-5B 4/30/03 9:41 AM Page 4

5-28
CHASFRONT FORK
EC556000
HANDLING NOTE
NOTE:
The front fork requires careful attention. So it is
recommended that the front fork be maintained
at the dealers.
cC
To prevent an accidental explosion of air,
the following instructions should be ob-
served:
9The front fork with a built-in piston rod
has a very sophisticated internal con-
struction and is particularly sensitive to
foreign material.
Use enough care not to allow any foreign
material to come in when the oil is re-
placed or when the front fork is disassem-
bled and reassembled.
9Before removing the cap bolts or front
forks, be sure to extract the air from the air
chamber completely.
EC553000
REMOVAL POINTSEC553160
Cap bolt
1. Remove:
9Cap bolt 1
From the outer tube.
NOTE:
Before removing the front fork from the machine,
loosen the cap bolt.
2. Remove:
9Cap bolt 1
NOTE:
Hold the locknut 2and remove the cap bolt.
5XE-9-30-5B 4/30/03 9:41 AM Page 6