2003 YAMAHA TTR125 Cylinder head

CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS
................................. 4-1
MUFFLER
................................................. 4-2
CARBURETOR
......................................... 4-3
CYLINDER HEAD
................................... 4-12
CAMSHAFT AND ROCKER ARMS
....... 4-20
VALVES AND VALVE SPRINGS
........... 4-24
CYLINDER AND PISTON
....................... 4-32
CLUTCH AND PRIMARY
DRIVEN GEAR
........................................ 4-40
OIL PUMP
............................................... 4-49
KICK AXLE AND SHIFT SHAFT
............ 4-53
CDI MAGNETO
....................................... 4-58
ENGINE REMOVAL
................................ 4-61
CRANKCASE, CRANKSHAFT
AND BALANCER
.................................... 4-65
TRANSMISSION, SHIFT CAM
AND SHIFT FORK
.................................. 4-73
CHAPTER 5
CHASSIS
FRONT WHEEL AND FRONT BRAKE
(TT-R125)
.................................................. 5-1
FRONT WHEEL (TT-R125LW)
................. 5-8
FRONT BRAKE (TT-R125LW)
............... 5-12
REAR WHEEL AND REAR BRAKE
....... 5-24
FRONT FORK
......................................... 5-32
HANDLEBAR
.......................................... 5-41
STEERING
.............................................. 5-49
SWINGARM
............................................ 5-55
REAR SHOCK ABSORBER
ASSEMBLY
............................................. 5-62
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS
AND WIRING DIAGRAM
.......................... 6-1
IGNITION SYSTEM
................................... 6-2

1 - 15
GEN
INFO
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
TT-R125
Engine mounting
Muffler
Steering Steering stem to
handlebar
Suspension Front Steering stem to
front fork
Rear For link type
Rear Installation of shock
absorber
Rear Installation of swing-
arm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel systemFrame to engine
Frame to engine bracket
Engine bracket to engine
Muffler to cylinder head
Muffler to rear fender bracket
Muffler to seat pillar tube
Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of wheel axle
Wheel to sprocket
Camshaft lever to camshaft
Camshaft lever to camshaft
Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.

1 - 16
GEN
INFO
TORQUE-CHECK POINTS
TT-R125LW
Engine mounting
Muffler
Steering Steering stem to
handlebar
Suspension Front Steering stem to
front fork
Rear For link type
Rear Installation of shock
absorber
Rear Installation of swing-
arm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel systemFrame to engine
Frame to engine bracket
Engine bracket to engine
Muffler to cylinder head
Muffler to rear fender bracket
Muffler to seat pillar tube
Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Front fork to upper bracket
Front fork to lower bracket
Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Shock absorber to frame
Tightening of pivot shaft
Tightening of wheel axle
Tightening of wheel axle
Wheel to sprocket
Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to joint
Brake hose to joint
Brake master cylinder to handlebar
Tightening of bleed screw
Brake camshaft lever to brake camshaft
Fuel tank to fuel cock
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.

SPEC
2 - 7
MAINTENANCE SPECIFICATIONS
EC212000
MAINTENANCE SPECIFICATIONS
EC212100
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.03 mm
(0.0012 in)
Cylinder:
Bore size 54.000 ~ 54.019 mm
(2.1260 ~ 2.1267 in)----
Out of round limit ---- 0.05 mm
(0.0020 in)
Camshaft:
Drive method Chain drive (left) ----
Cam dimensions
Intake“A”25.881 ~ 25.981 mm
(1.0189 ~ 1.0229 in)25.851 mm
(1.0178 in)
“B”21.195 ~ 21.295 mm
(0.8344 ~ 0.8384 in)21.165 mm
(0.8333 in)
Exhaust“A”25.841 ~ 25.941 mm
(1.0174 ~ 1.0213 in)25.811 mm
(1.0162 in)
“B”21.050 ~ 21.150 mm
(0.8287 ~ 0.8327 in)21.020 mm
(0.8276 in)
Camshaft runout limit ---- 0.03 mm
(0.0012 in)

SPEC
2 - 13
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Spark plug M10 × 1.0 1 13 1.3 9.4
Cylinder head bolt M8 × 1.25 4 22 2.2 16
Cylinder head bolt M6 × 1.0 2 10 1.0 7.2
Oil pressure check bolt M6 × 1.0 1 7 0.7 5.1
Cylinder head side cover M6 × 1.0 2 10 1.0 7.2
Tappet cover M45 × 1.5 2 18 1.8 13
Timing chain guide M6 × 1.0 1 10 1.0 7.2
Adjusting screw (valve) and locknut M5 × 0.5 2 8 0.8 5.8
Camshaft sprocket M8 × 1.25 1 20 2.0 14
Bearing plate cover (camshaft) M6 × 1.0 1 10 1.0 7.2
Timing chain tensioner cap bolt M6 × 1.0 1 8 0.8 5.8
Timing chain tensioner M6 × 1.0 2 10 1.0 7.2
Oil pump assembly M6 × 1.0 2 7 0.7 5.1
Oil pump cover M5 × 0.8 1 5 0.5 3.6
Engine oil drain bolt M12 × 1.5 1 20 2.0 14
Carburetor joint M6 × 1.0 2 10 1.0 7.2
Carburetor joint clamp (air filter) M4 × 0.7 1 2 0.2 1.4
Coasting enricher cover M4 × 0.7 2 2 0.2 1.4
Air filter case M6 × 1.0 3 7 0.7 5.1
Muffler M6 × 1.0 2 10 1.0 7.2
Muffler M10 × 1.25 1 60 6.0 43
Muffler M8 × 1.25 1 30 3.0 22
Muffler guard M6 × 1.0 7 10 1.0 7.2
Spark arrester M6 × 1.0 3 10 1.0 7.2
Crankcase M6 × 1.0 10 10 1.0 7.2
Left crankcase cover M6 × 1.0 7 10 1.0 7.2
Drive sprocket cover M6 × 1.0 2 12 1.2 8.7
Right crankcase cover M6 × 1.0 9 10 1.0 7.2
Lead guide (CDI magneto lead) M6 × 1.0 1 7 0.7 5.1
Timing mark accessing screw M14 × 1.5 1 7 0.7 5.1
Crankshaft end accessing screw M32 × 1.5 1 7 0.7 5.1
Kickstarter crank M12 × 1.0 1 50 5.0 36
Primary drive gear M12 × 1.0 1 70 7.0 50
Clutch spring M5 × 0.8 4 6 0.6 4.3
Clutch boss M12 × 1.0 1 60 6.0 43
Adjusting screw (push rod) and locknut M6 × 1.0 1 8 0.8 5.8
Bearing plate cover (main axle) M6 × 1.0 2 7 0.7 5.1
Drive sprocket M5 × 0.8 2 6 0.6 4.3
Shift arm M6 × 1.0 1 10 1.0 7.2
Shift rod and shift pedal M6 × 1.0 1 7 0.7 5.1
Shift rod and shift arm M6 × 1.0 1 7 0.7 5.1
Shift pedal M6 × 1.0 1 12 1.2 8.7
Segment M6 × 1.0 1 12 1.2 8.7
Stopper lever M6 × 1.0 1 10 1.0 7.2

SPEC
2 - 14
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each ride.
Cylinder head tightening sequence

SPEC
2 - 17
MAINTENANCE SPECIFICATIONS
NOTE:
1. First, tighten the ring nut approximately 38 Nm (3.8 m • kg, 27 ft • lb) by using the ring nut
wrench and turn the steering right and left a few times; then loosen the ring nut one turn.
2. Retighten the ring nut 20 Nm (2.0 m • kg, 14 ft • lb). Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Upper bracket and inner tube M8 × 1.25 2 25 2.5 18
Lower bracket and inner tube M10 × 1.25 2 60 6.0 43
Upper bracket and steering stem M22 × 1.0 1 110 11.0 80
Handlebar upper holder and upper bracket M8 × 1.25 4 23 2.3 17
Steering stem and ring nut M25 × 1.0 1 Refer to NOTE.
Front fork and cap bolt M25 × 1.0 2 23 2.3 17
Front fork and damper rod M10 × 1.0 2 23 2.3 17
Front fork and brake cable holder M6 × 1.0 1 7 0.7 5.1
Number plate M6 × 1.0 1 7 0.7 5.1
Starter knob M11 × 1.25 1 1 0.1 0.7
Starter knob stay M6 × 1.0 2 10 1.0 7.2
Grip cap upper and lower M5 × 0.8 2 4 0.4 2.9
Throttle cable cap M4 × 0.7 2 2 0.2 1.4
Brake lever mounting (bolt) M6 × 1.0 1 7 0.7 5.1
Brake lever mounting (nut) M6 × 1.0 1 7 0.7 5.1
Brake lever holder M5 × 0.8 2 4 0.4 2.9
Clutch lever mounting (bolt) M6 × 1.0 1 7 0.7 5.1
Clutch lever mounting (nut) M6 × 1.0 1 7 0.7 5.1
Clutch lever holder M5 × 0.8 2 4 0.4 2.9
Front wheel axle and axle nut M12 × 1.25 1 45 4.5 32
Front brake camshaft lever and camshaft M6 × 1.0 1 10 1.0 7.2
Rear wheel axle and axle nut M12 × 1.25 1 60 6.0 43
Rear brake camshaft lever and camshaft M6 × 1.0 1 10 1.0 7.2
Brake pedal mounting M10 × 1.25 1 30 3.0 22
Brake pedal position locknut M6 × 1.0 1 7 0.7 5.1
Front wheel nipple (spoke)—36 2 0.2 1.4
Rear wheel nipple (spoke)—36 3 0.3 2.2
Driven sprocket (nut) M10 × 1.25 4 43 4.3 31
Driven sprocket (stud) M10 × 1.25 4 30 3.0 22
Sidestand mounting (nut) M10 × 1.25 1 44 4.4 32
Engine mounting:
Engine bracket (front) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (front) and engine M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and cylinder head M8 × 1.25 1 40 4.0 29
Engine and frame (rear) M8 × 1.25 2 40 4.0 29
Pivot shaft and nut M12 × 1.25 1 53 5.3 38
Relay arm and swingarm M12 × 1.25 1 53 5.3 38

SPEC
2 - 22
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each ride.Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Bead stopper M8 × 1.25 1 3 0.3 2.2
Driven sprocket (nut) M10 × 1.25 4 43 4.3 31
Driven sprocket (stud) M10 × 1.25 4 30 3.0 22
Sidestand mounting (nut) M10 × 1.25 1 44 4.4 32
Engine mounting:
Engine bracket (front) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (front) and engine M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and frame M8 × 1.25 2 40 4.0 29
Engine bracket (upper) and cylinder head M8 × 1.25 1 40 4.0 29
Engine and frame (rear) M8 × 1.25 2 40 4.0 29
Pivot shaft and nut M12 × 1.25 1 53 5.3 38
Relay arm and swingarm M12 × 1.25 1 53 5.3 38
Relay arm and connecting arm M10 × 1.25 1 35 3.5 25
Connecting arm and frame M10 × 1.25 1 35 3.5 25
Rear shock absorber assembly and frame M12 × 1.25 1 53 5.3 38
Rear shock absorber assembly and relay arm M10 × 1.25 1 35 3.5 25
Rear shock absorber and locknut (preload) M46 × 1.5 1 42 4.2 30
Drive chain tensioner (upper) M8 × 1.25 1 23 2.3 17
Drive chain tensioner (lower) M6 × 1.0 1 7 0.7 5.1
Drive chain support and swingarm M6 × 1.0 2 7 0.7 5.1
Drive chain guide and swingarm M6 × 1.0 2 7 0.7 5.1
Drive chain guard mounting M6 × 1.0 2 7 0.7 5.1
Fuel tank mounting M6 × 1.0 2 10 1.0 7.2
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
Front fender mounting M6 × 1.0 4 7 0.7 5.1
Rear fender mounting M6 × 1.0 4 7 0.7 5.1
Flap guard mounting M6 × 1.0 2 4 0.4 2.9
Left side cover mounting M6 × 1.0 2 7 0.7 5.1
Seat mounting M6 × 1.0 2 7 0.7 5.1