steering YAMAHA TTR125 2002 Owners Manual

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 - 2
GEN
INFO

MACHINE IDENTIFICATION
EC120001
MACHINE IDENTIFICATION
There are two significant reasons for knowing
the serial number of your machine:
1. When ordering parts, you can give the
number to your Yamaha dealer for positive
identification of the model you own.
2. If your machine is stolen, the authorities
will need the number to search for and
identify your machine.
EC121001
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number
1
is
stamped on the right of the steering head pipe.
EC123001
ENGINE SERIAL NUMBER
The engine serial number
1
is stamped into
the elevated part of the right-side of the
engine.
EC124000
MODEL LABEL
The model label
1
is affixed to the frame
under the rider’s seat. This information will be
needed to order spare parts.

1 - 7
GEN
INFO
SPECIAL TOOLS
YM-1312-A, 90890-01312Fuel level gauge
This gauge is used to measure the fuel level in the
float chamber.YM-1312-A 90890-01312
YU-33270-B, 90890-01362 Flywheel puller
This tool is used to remove the rotor.YU-33270-B 90890-01362
YM-33963, 90890-01367
YM-33281, 90890-01400Fork seal driver weight
Fork seal driver attachment
These tools are used to installing the fork oil seal.YM-33963
YM-3328190890-01367
90890-01400
YU-33975, 90890-01403 Steering nut wrench
This tool is used when tighten the steering ring nut to
specification.YU-33975 90890-01403
YS-1880-A, 90890-01701 Sheave holder
This tool is used for when loosening or tightening the
flywheel magneto securing nut.YS-1880-A 90890-01701
YU-3112-C, 90890-03112 Pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.YU-3112-C 90890-03112
YU-8036-B
90890-03113Inductive tachometer
Engine tachometer
This tool is needed for observing engine rpm.YU-8036-B 90890-03113
YM-4019, 90890-04019 Valve spring compressor
This tool is needed to remove and install the valve
assemblies.YM-4019 90890-04019
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.YM-91042 90890-04086
Part number Tool name/How to use Illustration

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
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
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 - 15
MAINTENANCE SPECIFICATIONS
EC212201
CHASSIS
TT-R125
Item Standard Limit
Steering system:
Steering bearing type (upper) Angular bearing ----
(lower) Taper roller bearing ----
Front suspension:
Front fork travel 180 mm (7.09 in) ----
Fork spring free length 327 mm (12.87 in) 322 mm (12.68 in)
Spring rate, STD K = 3.00 N/mm
(0.310 kg/mm, 17.4 lb/in)----
Optional spring/spacer No ----
Oil capacity 159 cm
3
(5.60 Imp oz, 5.38 US oz)----
Oil level 122 mm (4.80 in) ----
Oil grade Fork oil 10W or equivalent ----
Inner tube outer diameter 30 mm (1.18 in) ----
Front fork top end Zero mm (Zero in) ----
Rear suspension:
Shock absorber travel 65 mm (2.56 in) ----
Spring free length 175 mm (6.89 in) ----
Fitting length 165 mm (6.50 in) ----
Spring rate, STD K = 48.1 N/mm
(4.9 kg/mm, 274 lb/in)----
Optional spring No ----
Enclosed gas pressure 1,500 kPa
(15 kg/cm
2, 213 psi)----
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/material 17 ´ 1.40/Steel ----
Rear rim size/material 14 ´ 1.60/Steel ----
Rim runout limit:
Radial ---- 2.0 mm (0.08 in)
Lateral ---- 2.0 mm (0.08 in)
Drive chain:
Type/manufacturer DID428HD/DAIDO ----
Number of links 116 links ----
Chain slack 35 ~ 50 mm (1.4 ~ 2.0 in) ----
Chain length (10 links) ----121.4 mm
(4.78 in)

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 - 19
MAINTENANCE SPECIFICATIONS
TT-R125LW
Item Standard Limit
Steering system:
Steering bearing type (upper) Angular bearing ----
(lower) Taper roller bearing ----
Front suspension:
Front fork travel 180 mm (7.09 in) ----
Fork spring free length 339 mm (13.35 in) 334 mm (13.15 in)
Spring rate, STD K = 3.20 N/mm
(0.330 kg/mm, 18.5 lb/in)----
Optional spring/spacer No ----
Oil capacity 156 cm
3
(5.49 Imp oz, 5.27 US oz)----
Oil level 130 mm (5.12 in) ----
Oil grade Fork oil 10W or equivalent ----
Inner tube outer diameter 30 mm (1.18 in) ----
Front fork top end Zero mm (Zero in) ----
Rear suspension:
Shock absorber travel 65 mm (2.56 in) ----
Spring free length 178 mm (7.01 in) ----
Fitting length 165 mm (6.50 in) ----
Spring rate, STD K = 58.9 N/mm
(6.0 kg/mm, 336 lb/in)----
Optional spring No ----
Enclosed gas pressure 1,500 kPa
(15 kg/cm
2, 213 psi)----
Wheel:
Front wheel type Spoke wheel ----
Rear wheel type Spoke wheel ----
Front rim size/material 19 ´ 1.40/Steel ----
Rear rim size/material 16 ´ 1.60/Steel ----
Rim runout limit:
Radial ---- 2.0 mm (0.08 in)
Lateral ---- 2.0 mm (0.08 in)
Drive chain:
Type/manufacturer DID428HD/DAIDO ----
Number of links 122 links ----
Chain slack 35 ~ 50 mm (1.4 ~ 2.0 in) ----
Chain length (10 links) ----121.4 mm
(4.78 in)
Front disc brake:
Disc outside dia. ´ Thickness 220 ´ 3.0 mm (8.66 ´ 0.12 in)220 ´ 2.5 mm
(8.66 ´ 0.10 in)
Deflection limit ----0.15 mm (0.006 in)
Pad thickness 4.0 mm (0.16 in)0.8 mm (0.03 in)
Master cylinder inside dia. 11.0 mm (0.433 in) ----
Caliper cylinder inside dia. 22.22 mm (0.875 in) ´ 2 ----
Brake fluid type DOT #4 ----

SPEC
2 - 21
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 hose holder M6 ´ 1.0 2 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
Front brake master cylinder M6 ´ 1.0 2 9 0.9 6.5
Front brake master cylinder 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 adjuster and locknut M6 ´ 0.75 1 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 brake master cylinder and joint M10 ´ 1.25 1 26 2.6 19
Front brake hose and joint M10 ´ 1.25 1 14 1.4 10
Front brake hose union bolt M10 ´ 1.25 1 26 2.6 19
Front brake caliper and front fork M8 ´ 1.25 2 30 3.0 22
Brake caliper support bolt M8 ´ 1.25 1 22 2.2 16
Front brake caliper and bleed screw M7 ´ 1.0 1 6 0.6 4.3
Front wheel axle and axle nut M12 ´ 1.25 1 45 4.5 32
Front brake disc and wheel hub M6 ´ 1.0 4 12 1.2 8.7
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

3 - 1
INSP
ADJ

MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
Dealer
NoteItem Checks and maintenance jobsInitial Every
10 hours
(1 month)60 hours
(6 months)120 hours
(12 months)
*
Fuel lineCheck fuel hoses for cracks or damage.
Replace if necessary.
Spark plugCheck condition.
Clean, regap or replace if necessary.
*
ValvesCheck valve clearance.
Adjust if necessary.
Air filter Clean or replace element if necessary.
*
CarburetorCheck engine idling speed and starter operation.
Adjust if necessary.
Exhaust systemsCheck for leakage.
Retighten if necessary.
Replace gasket if necessary.
Engine oilCheck oil level and vehicle for oil leakage.
Correct if necessary.
Change. (Warm engine before draining.)
ClutchCheck operation.
Adjust or replace cable.
*
Front brakeCheck operation.
Adjust brake lever free play.
Check fluid level and leakage. (TT-R125LW only)Every ride
*
Rear brakeCheck operation.
Adjust brake pedal free play and replace brake
shoes if necessary.Every ride
*
WheelsCheck balance, runout, spoke tightness and for
damage.
Tighten spokes and rebalance, replace if
necessary.
*
TiresCheck tread depth and for damage.
Replace if necessary.
Check air pressure.
Correct if necessary.
*
Wheel bearingsCheck bearing for looseness or damage.
Replace if necessary.
*
SwingarmCheck swingarm pivoting point for play.
Correct if necessary.
Lubricate with molybdenum disulfide grease.
Drive chainCheck chain slack.
Adjust if necessary. Make sure that the rear wheel
is properly aligned.
Clean and lubricate.Every ride
*
Steering bearingsCheck bearing play and steering for roughness.
Correct accordingly.
Lubricate with lithium soap base grease every 120
hours.
SidestandCheck operation.
Lubricate and repair if necessary.
3