2012 YAMAHA YZ125LC radiator

CONTENTS
CHAPTER 1
GENERAL INFOR-
MATION
LOCATION OF IMPORTANT
LABELS............................ 1-1
DESCRIPTION ................. 1-5
CONSUMER
INFORMATION................. 1-6
INCLUDED PARTS .......... 1-6
IMPORTANT
INFORMATION................. 1-6
CHECKING OF
CONNECTION .................. 1-7
SPECIAL TOOLS ............. 1-8
CONTROL
FUNCTIONS ................... 1-11
STARTING AND
BREAK-IN ...................... 1-12
TORQUE-CHECK
POINTS........................... 1-13
CLEANING AND
STORAGE ...................... 1-14
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-2
TIGHTENING TORQUES . 2-7
CABLE ROUTING
DIAGRAM ....................... 2-13
CHAPTER 3
REGULAR INSPEC-
TION AND AD-
JUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS .......................... 3-9
ELECTRICAL ................. 3-19
CHAPTER 4
ENGINE
SEAT, FUEL TANK AND
SIDE COVERS.................. 4-1
EXHAUST PIPE AND
SILENCER ........................ 4-3
RADIATOR ....................... 4-5
CARBURETOR AND
REED VALVE ................... 4-7
CYLINDER HEAD, CYLIN-
DER AND PISTON ......... 4-12
CLUTCH ......................... 4-19
KICK SHAFT AND
SHIFT SHAFT ................. 4-23
YPVS GOVERNOR......... 4-28
WATER PUMP................ 4-30
CDI MAGNETO............... 4-33
ENGINE REMOVAL ....... 4-35
CRANKCASE AND
CRANKSHAFT ............... 4-39
TRANSMISSION, SHIFT
CAM AND SHIFT
FORK .............................. 4-44
CHAPTER 5
CHASSIS
FRONT WHEEL AND
REAR WHEEL ..................5-1
FRONT BRAKE AND
REAR BRAKE ..................5-6
FRONT FORK .................5-16
HANDLEBAR..................5-24
STEERING ......................5-29
SWINGARM ....................5-33
REAR SHOCK
ABSORBER ....................5-38
CHAPTER 6
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........6-2
IGNITION SYSTEM...........6-3
CHAPTER 7
TUNING
ENGINE.............................7-1
CHASSIS ..........................7-6

1-5
DESCRIPTION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
1. Clutch lever
2. Engine stop switch
3. Front brake lever
4. Throttle grip
5. Radiator cap
6. Fuel tank cap
7. Kickstarter crank
8. Fuel tank
9. Radiator
10. Coolant drain bolt
11. Check bolt (Transmission oil level)
12. Rear brake pedal
13. Valve joint14. Fuel cock
15. Air filter
16. Drive chain
17. Shift pedal
18. Starter knob
19. Front fork

1-9
SPECIAL TOOLS
Fuel level gauge "1"
YM-1312-A, 90890-01312
Fuel level gauge adaptor "2"
YM-01470, 90890-01470This gauge is used to measure the
fuel level in the float chamber.
Radiator cap tester
YU-24460-01, 90890-01325
Radiator cap tester adapter
YU-33984, 90890-01352These tools are used for checking
the cooling system.
Flywheel puller
YU-33270-B, 90890-01362 These tool is used to split the crank-
case.
Steering nut wrench
YU-33975, 90890-01403 This tool is used when tighten the
steering ring nut to specification.
Cap bolt wrench
YM-01500, 90890-01500This tool is used to loosen or tighten
the base valve.
Cap bolt ring wrench
YM-01501, 90890-01501This tool is used to loosen or tighten
the damper assembly. Tool name/Part number How to use Illustration

2-5
MAINTENANCE SPECIFICATIONS
CHASSISCooling:
Radiator core size:
Width 107.8 mm (4.24 in) ----
Height (left) 240 mm (9.45 in) ----
Height (right) 220 mm (8.66 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure 95–125 kPa (0.95–1.25 kg/cm
2, 13.5–17.8 psi) ----
Radiator capacity (total) 0.56 L (0.49 Imp qt, 0.59 US qt) ----
Water pump:
Type Single-suction centrifugal pump ----
Item Standard Limit
Steering system:
Steering bearing typeTaper roller bearing ----
Front suspension: USA, CDN, ZA, AUS,
NZEUROPE
Front fork travel 300 mm (11.8 in)←----
Fork spring free length 454 mm (17.9 in)←449 mm (17.7
in)
Spring rate, STD K=4.1 N/mm (0.418 kg/
mm, 23.4 lb/in)←----
Optional spring Yes←----
Oil capacity 524 cm
3 (18.4 Imp oz,
17.7 US oz)526 cm3 (18.5 Imp oz,
17.8 US oz)----
Oil grade Suspension oil "S1"←----
Inner tube outer diameter 48 mm (1.89 in)←----
Front fork top end 5 mm (0.2 in)←----
Rear suspension: USA, CDN, ZA, AUS,
NZEUROPE
Shock absorber travel 131.5 mm (5.18 in)←----
Spring free length Approx.265 mm (10.43
in)←----
Fitting length*----
I.D. mark (Red/1) 258 mm (10.16 in) 252 mm (9.92 in) ----
I.D. mark (Red/2) 264 mm (10.39 in) 258 mm (10.16 in) ----
I.D. mark (Red/3) 255.5 mm (10.06 in) 249.5 mm (9.82 in) ----
Preload length
1.5–18 mm (0.06–0.71
in)←----
Spring rate, STD K=46.0 N/mm (4.70 kg/
mm, 263.2 lb/in)←----
Optional spring Yes←----
Enclosed gas pressure 1,000 kPa (10 kg/cm
2,
142 psi)←----
* Spring specification varies according to the differ-
ence in the production lot.Item Standard Limit

2-7
TIGHTENING TORQUES
ELECTRICAL
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque tightening after break-in or before each race.
Item Standard Limit
Ignition system:
Ignition timing (B.T.D.C.) 0.48 mm (0.019 in) ----
Advancer type Electrical ----
CDI:
Magneto-model (stator)/Manufacturer 1C3-10/YAMAHA ----
Charging coil 1 resistance (color) 720–1,080 Ωat 20 °C (68 °F) (Green/
White-Black/Red)----
Charging coil 2 resistance (color) 44–66 Ωat 20 °C (68 °F) (Black-Green/
Blue)----
Pickup coil resistance (color) 248–372 Ωat 20 °C (68 °F) (White/Blue-
White/Red)----
CDI unit-model/manufacturer 1C3-10/YAMAHA ----
Ignition coil:
Model/manufacturer 1C3-00/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.24–0.36 Ωat 20 °C (68 °F) ----
Secondary winding resistance 5.7–8.5 kΩat 20 °C (68 °F) ----
Spark plug cap:
Resistance 4–6 kΩat 20 °C (68 °F) ----
ItemThread
sizeQ'ty Tightening torque Remarks
Spark plug M14S 1 20 Nm (2.0 m•kg, 14 ft•lb)
Cylinder head (nut) M8 5 28 Nm (2.8 m•kg, 20 ft•lb)Copper
washer
Cylinder head (stud) M8 5 13 Nm (1.3 m•kg, 9.4 ft•lb)
Cylinder (nut) M8 4 30 Nm (3.0 m•kg, 22 ft•lb)
Cylinder (stud) M10 4 13 Nm (1.3 m•kg, 9.4 ft•lb)
Power valve:
Cover M5 4 5 Nm (0.5 m•kg, 3.6 ft•lb) YPVS
Link lever M4 1 4 Nm (0.4 m•kg, 2.9 ft•lb) YPVS
Holder (power valve) M5 4 8 Nm (0.8 m•kg, 5.8 ft•lb) YPVS
Push rod M5 1 5 Nm (0.5 m•kg, 3.6 ft•lb) YPVS
Thrust plate M5 1 4 Nm (0.4 m•kg, 2.9 ft•lb) YPVS
Governor fork M4 2 5 Nm (0.5 m•kg, 3.6 ft•lb) YPVS
Housing M5 3 4 Nm (0.4 m•kg, 2.9 ft•lb) YPVS
Water pump housing cover M6 4 10 Nm (1.0 m•kg, 7.2 ft•lb)
Coolant drain bolt M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)Copper
washer
Radiator M6 6 10 Nm (1.0 m•kg, 7.2 ft•lb)
Radiator panel M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Radiator hose clamp M6 8 2 Nm (0.2 m•kg, 1.4 ft•lb)

2-10
TIGHTENING TORQUES
△Brake pedal mounting M8 1 26 Nm (2.6 m•kg, 19 ft•lb)
△Rear brake master cylinder and frame M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Rear brake master cylinder cap M4 2 2 Nm (0.2 m•kg, 1.4 ft•lb)
△
Rear brake hose union bolt (caliper) M10 1 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△Rear brake hose union bolt (master cylin-
der)M10 1 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△Rear wheel axle and axle nut M20 1 125 Nm (12.5 m•kg, 90 ft•lb)
△Nipple (spoke) — 72 3 Nm (0.3 m•kg, 2.2 ft•lb)
△Driven sprocket and wheel hub M8 6 42 Nm (4.2 m•kg, 30 ft•lb)
△Disc cover and rear brake caliper M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
△Protector and rear brake caliper M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Drive chain puller adjust bolt and locknut M8 2 19 Nm (1.9 m•kg, 13 ft•lb)
Engine :
△Engine and frame (front) M10 1 64 Nm (6.4 m•kg, 46 ft•lb)
△Engine and frame (lower) M10 1 64 Nm (6.4 m•kg, 46 ft•lb)
△Engine bracket and frame M8 2 34 Nm (3.4 m•kg, 24 ft•lb)
△Engine bracket and engine M8 1 34 Nm (3.4 m•kg, 24 ft•lb)
△Pivot shaft and nut M16 1 85 Nm (8.5 m•kg, 61 ft•lb)
△Relay arm and swingarm M14 1 70 Nm (7.0 m•kg, 50 ft•lb)
△Relay arm and connecting rod M14 1 80 Nm (8.0 m•kg, 58 ft•lb)
△Connecting rod and frame M14 1 80 Nm (8.0 m•kg, 58 ft•lb)
△Rear shock absorber and frame M10 1 56 Nm (5.6 m•kg, 40 ft•lb)
△Rear shock absorber and relay arm M10 1 53 Nm (5.3 m•kg, 38 ft•lb)
△Rear frame and frame (upper) M8 1 32 Nm (3.2 m•kg, 23 ft•lb)
△Rear frame and frame (lower) M8 2 29 Nm (2.9 m•kg, 21 ft•lb)
△Swingarm and brake hose holder M54 3 Nm (0.3 m•kg, 2.2 ft•lb)
Swingarm and patch M4 4 2 Nm (0.2 m•kg, 1.4 ft•lb)
Drive chain tensioner M8 2 16 Nm (1.6 m•kg, 11 ft•lb)
Drive chain support and swingarm M6 37 Nm (0.7 m•kg, 5.1 ft•lb)
Seal guard and swingarm M5 4 6 Nm (0.6 m•kg, 4.3 ft•lb)
Cable guide and frame M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
△Fuel tank boss and frame M10 2 20 Nm (2.0 m•kg, 14 ft•lb)
△Fuel tank M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
△Fuel tank and fuel cock M6 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Fuel tank and seat set bracket M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Fuel tank and hooking screw (fitting band) M6 1 7 Nm (0.7 m•kg, 5.1 ft•lb)
Fuel tank and fuel tank bracket M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Air scoop and fuel tank M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Air scoop and radiator guard (lower) M6 2 6 Nm (0.6 m•kg, 4.3 ft•lb)
△Front fender M6 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Rear fender (front) M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Rear fender (rear) M6 2 12 Nm (1.2 m•kg, 8.7 ft•lb)
△Side cover M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Seat M8 2 19 Nm (1.9 m•kg, 13 ft•lb)ItemThread
sizeQ'ty Tightening torque Remarks

2-13
CABLE ROUTING DIAGRAM
CABLE ROUTING DIAGRAM
1. "ENGINE STOP" button lead
2. Throttle cable
3. Clutch cable
4. Ground lead
5. High tension cord
6. Clamp
7. Air vent hose
8. Radiator breather hose
9. CDI magneto lead10. YPVS breather hose
11. Engine bracket (right)
12. Engine bracket (left)
13. Crankcase breather hose
14. Overflow hose
15. Connector cover
A. Pass the clutch cable on the out-
side of the throttle cable and
"ENGINE STOP" button lead.B. Align the throttle cable locating
tape with the cable guide.
C. Pass the throttle cable, clutch
cable and "ENGINE STOP" but-
ton lead above the radiator
hose.

2-14
CABLE ROUTING DIAGRAM
D. Install the ignition coil, side core
and ground lead together to the
frame. Take care to fasten the
ground lead so that its terminal
is within the indicated range.
E. Clamp the throttle cable and
high tension cord to the frame.
F. Clamp the clutch cable to the left
engine bracket. Clamp the
clutch cable below the position-
ing grommet.
G. Pass the air vent hose back of
the throttle cable.
H. Pass the air vent hose, overflow
hose and crankcase breather
hose between the frame and
connecting rod.
I. Pass the radiator breather hose
and YPVS breather hose out-
side the engine bracket and in-
side the down tube. Then pass
the radiator breather hose inside
the YPVS breather hose.
J. Clamp the CDI magneto lead,
radiator breather hose and
YPVS breather hose to the
frame.
K. Clamp to the frame the CDI
magneto lead and radiator
breather hose. Take care to
clamp them above the projection
on the frame.
L. Locate the clamp ends in the ar-
rowed range.
M. Direct the clip with its finger grip
facing forward.
N. Tighten the clamp with its bolt
head facing the left side of the
chassis (on both sides of the
carburetor joint and the air filter
joint).
O. Pass the air vent hose, overflow
hose and crankcase breather
hose so that they do not contact
the rear shock absorber.
P. Bring the connector cover into
contact with the coupler.