2012 YAMAHA YZ125LC Owners Manual

4-27
KICK SHAFT AND SHIFT SHAFT
3. Install:
• Kick shaft assembly "1"
• Apply the transmission oil on the
kick shaft.
• Slide the kick shaft assembly into
the crankcase, make sure the clip
"2" and kick shaft stopper "a" fit into
their home position "b", "c".
4. Hook:
• Torsion spring "1"
Turn the torsion spring clockwise and
hook into the proper hole "a" in the
crankcase.
INSTALLING THE KICK IDLE
GEAR
1. Install:
• Kick idle gear "1"
• Washer "2"
• Circlip "3"
Apply the transmission oil on the kick
idle gear inner circumference.
INSTALLING THE PRIMARY DRIVE
GEAR
1. Install:
• Spacer "1"
• Primary drive gear "2"
•Bolt "3"
Install the primary drive gear with its
depressed side toward you.
2. Install:
• Primary driven gear
Refer to "CLUTCH" section.
3. Tighten:
• Bolt (primary drive gear) "1"
Place an aluminum plate "a" between
the teeth of the primary drive gear
and driven gear.
4. Install:
• Dowel pin "1"
• Gasket [crankcase cover (right)]
"2"
5. Install:
• Crankcase cover (right) "1"
Mesh the governor gear "2", and im-
peller shaft gear "3" with primary
drive gear "4".
6. Install:
• Bolt [crankcase cover (right)] "1"
Tighten the bolts in stage, using a
crisscross pattern.
7. Install:
• Kick starter "1"
• Plain washer "2"
• Bolt (kick starter) "3"
Install the kick starter closest to but
not contacting the pillar tube "4".
8. Install:
• Shift pedal "1"
• Bolt (shift pedal) "2"
Align the upper line "a" of the shift
pedal with the center "b" of the crank-
case projection and rotate the shift
pedal counterclockwise until it first
engages. Then install the shift pedal.
Bolt (primary drive gear):
48 Nm (4.8 m•kg, 35
ft•lb)
Bolt [crankcase cover
(right)] :
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (kick starter) :
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (shift pedal) :
12 Nm (1.2 m•kg, 8.7
ft•lb)

4-28
YPVS GOVERNOR
YPVS GOVERNOR
REMOVING THE YPVS GOVERNOR
Order Part name Q'ty Remarks
Right crankcase coverRefer to "KICK SHAFT AND SHIFT SHAFT"
section.
1 Governor assembly 1
2 Dowel pin 1 Refer to removal section.
3 Retainer 1
4Ball 4
5 Retainer weight 1
6 Plain washer 4
7 Thrust bearing 2
8 Collar 1
9Plate 1
10 Compression spring 1
11 Governor gear 1
12 Governor shaft 1

4-29
YPVS GOVERNOR
REMOVING THE GOVERNOR
1. Remove:
• Dowel pin "1"
While compressing the spring, re-
move the dowel pin.
CHECKING THE GOVERNOR
GROOVE
1. Inspect:
• Washer "1"
•Collar "2"
Wear/Damage→Replace.
CHECKING THE BEARING
1. Inspect:
• Thrust bearing "1"
• Washer "2"
Wear/Damage→Replace.
INSTALLING THE GOVERNOR
1. Install:
• Governor gear "1"
• Compression spring "2"
• Plate "3"
• Washer "4"
• Thrust bearing "5"
•Collar "6"
• Retainer weight "7"
To governor shaft "8".
Apply the lithium soap base grease
on the thrust bearing.
2. Install:
• Ball "1"
• Retainer "2"
To governor shaft "3".
Apply the transmission oil on the re-
tainer and ball.
3. Install:
• Dowel pin "1"
• While compressing the spring, in-
stall the dowel pin.
• Make sure the dowel pin fits into the
groove "a" in the retainer.
4. Install:
• Governor assembly "1"
Align the groove "a" in the governor
with the fork "b" and set the governor
in the crankcase cover.

4-30
WATER PUMP
WATER PUMP
DISASSEMBLING THE WATER PUMP
Order Part name Q'ty Remarks
Crankcase cover (right)Refer to "KICK SHAFT AND SHIFT SHAFT"
section.
1 Water pump housing cover 1
2 Impeller shaft gear 1
3 Dowel pin 1
4 Plain washer 1
5 Impeller shaft assembly 1
6 Bearing 1 Refer to removal section.
7 Oil seal 2 Refer to removal section.

4-31
WATER PUMP
REMOVING THE OIL SEAL
• Replace the oil seal when transmis-
sion oil or coolant leaks out from the
water pump housing hole at the bot-
tom.
• Do not reuse the removed bearing
and oil seal.
1. Remove:
• Bearing "1"
2. Remove:
• Oil seal (outside) "1"
• Oil seal (inside) "2"
CHECKING THE IMPELLER SHAFT
1. Inspect:
• Impeller shaft "1"
Bend/wear/damage→Replace.
Fur deposits→Clean.
CHECKING THE IMPELLER SHAFT
GEAR
1. Inspect:
• Gear teeth "a"
Wear/damage→Replace.CHECKING THE BEARING
1. Inspect:
•Bearing
Rotate inner race with a finger.
Rough spot/seizure→Replace.
CHECKING THE OIL SEAL
1. Inspect:
• Oil seal "1"
Wear/damage→Replace.
INSTALLING THE OIL SEAL
1. Install:
• Oil seal (inside) "1"
• Oil seal (outside) "2"
• Apply the lithium soap base grease
on the oil seal lip.
• Install the oil seal with its manufac-
ture's marks or numbers facing the
right crankcase cover "3".
2. Install:
•Bearing "1"
Install the bearing by pressing its out-
er race parallel.
INSTALLING THE IMPELLER
SHAFT
1. Install:
• Impeller shaft "1"
• Take care so that the oil seal lip is
not damaged or the spring does not
slip off its position.
• When installing the impeller shaft,
apply the lithium soap base grease
on the oil seal lip and impeller shaft.
And install the shaft while turning it.
2. Install:
• Washer "1"
• Dowel pin "2"
• Impeller shaft gear "3"
•Collar "4"
• Washer "5"
• Circlip "6"
Install the Impeller shaft gear with the
dowel pin fitted in the groove "a" in
the same gear.
3. Install:
• Dowel pin "1"
• Gasket (water pump housing cov-
er) "2"

4-32
WATER PUMP
4. Install:
• Water pump housing cover "1"
• Bolt (water pump housing cover)
"2"
• Copper washer (coolant drain
bolt) "3"
• Coolant drain bolt "4" Bolt (water pump hous-
ing cover):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Coolant drain bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)

4-33
CDI MAGNETO
CDI MAGNETO
REMOVING THE CDI MAGNETO
Order Part name Q'ty Remarks
Seat and fuel tankRefer to "SEAT, FUEL TANK AND SIDE
COVERS" section.
Bolt (Radiator) Refer to "RADIATOR" section.
Disconnect the CDI magneto lead.
1 Left crankcase cover 1
2 Nut (rotor) 1 Refer to removal section.
3 Rotor 1 Refer to removal section.
4 Stator 1
5 Woodruff key 1

4-34
CDI MAGNETO
REMOVING THE ROTOR
1. Remove:
• Nut (rotor) "1"
• Washer "2"
Use the rotor holding tool "3".
2. Remove:
• Rotor "1"
Use the flywheel puller "2".
When installing the flywheel puller,
turn it counterclockwise.
CHECKING THE CDI MAGNETO
1. Inspect:
• Rotor inner surface "a"
• Stator outer surface "b"
Damage→Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace CDI magne-
to and/or stator.
CHECKING THE WOODRUFF KEY
1. Inspect:
• Woodruff key "1"
Damage→Replace.INSTALLING THE CDI MAGNETO
1. Install:
• Stator "1"
• Screw (stator) "2"
Temporarily tighten the screw (stator)
at this point.
2. Install:
• Woodruff key "1"
• Rotor "2"
• Clean the tapered portions of the
crankshaft and rotor.
• When installing the woodruff key,
make sure that its flat surface "a" is
in parallel with the crankshaft center
line "b".
• When installing the rotor, align the
keyway "c" of the rotor with the
woodruff key.
3. Install:
• Washer "1"
• Nut (rotor) "2"
Use the rotor holding tool "3".4. Adjust:
• Ignition timing
Refer to "CHECKING THE IGNI-
TION TIMING" section in the
CHAPTER 3.
5. Tighten:
• Screw (stator) "1"
6. Check:
• Ignition timing
Re-check the ignition timing.
7. Connect:
• CDI magneto lead "1"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
8. Install:
• Gasket [crankcase cover (left)]
• Crankcase cover (left) "1"
• Screw [crankcase cover (left)] "2"
Tighten the screws in stage, using a
crisscross pattern.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YM-1189/90890-01189
Nut (rotor):
56 Nm (5.6 m•kg, 40
ft•lb)
Rotor holding tool:
YU-1235/90890-01235
Ignition timing (B.T.D.C):
0.48 mm (0.019 in)
Screw (stator):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Screw [crankcase cover
(left)]:
5 Nm (0.5 m•kg, 3.6
ft•lb)