length YAMAHA TTR125 2003 User Guide

2 - 25
SPEC

GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS
EC220001
GENERAL TORQUE SPECIFICATIONS
This chart specifies torque for standard fasten-
ers with standard I.S.O. pitch threads. Torque
specifications for special components or
assemblies are included in the applicable sec-
tions of this book. To avoid warpage, tighten
multi-fastener assemblies in a crisscross fash-
ion, in progressive stages, until full torque is
reached. Unless otherwise specified, torque
specifications call for clean, dry threads. Com-
ponents should be at room temperature.
A
(Nut)B
(Bolt)TORQUE
SPECIFICATION
Nm m•kg ft•lb
10 mm
12 mm
14 mm
17 mm
19 mm
22 mm6 mm
8 mm
10 mm
12 mm
14 mm
16 mm6
15
30
55
85
1300.6
1.5
3.0
5.5
8.5
134.3
11
22
40
61
94
A: Distance between flats
B: Outside thread diameter
EC230000
DEFINITION OF UNITS
Unit Read Definition Measure
mm
cmmillimeter
centimeter10
-3

meter
10
-2

meterLength
Length
kg kilogram 10
3

gram Weight
N Newton 1 kg
×
m/sec
2

Force
Nm
m • kgNewton meter
Meter kilogramN
×
m
m
×
kgTorque
Torque
Pa Pascal N/m
2

Pressure
N/mm Newton per millimeter N/mm Spring rate
L
cm
3

Liter
Cubic centimeter—
—Volume or capacity
Volume or capacity
r/min Revolution per minute—Engine speed

3 - 21
INSP
ADJ
DRIVE CHAIN INSPECTION
EC369002
DRIVE CHAIN INSPECTION
1. Remove:
Master link clip
Joint 1
Drive chain 2
2. Clean:
Drive chain
Place it in kerosene, and brush off as
much dirt as possible. Then remove the
chain from the kerosene and dry the
chain.
3. Measure:
Drive chain length (10 links) a
Out of specification → Replace.
Drive chain length (10 links):
: 121.4 mm (4.78 in)
4. Check:
Drive chain stiffness a
Clean and oil the chain and hold as
illustrated.
Stiff → Replace drive chain.
5. Install:
Drive chain 1
Joint 2
Master link clip 3
CAUTION:
Be sure to install the master link clip to the
direction as shown.
aTurning direction
New

3 - 24
INSP
ADJ
REAR SHOCK ABSORBER ASSEMBLY
INSPECTION
1. Inspect:
Swingarm smooth action
Abnormal noise/unsmooth action →
Grease the pivoting points or repair the
pivoting points.
Damage/oil leakage → Replace.
REAR SHOCK ABSORBER SPRING
PRELOAD ADJUSTMENT
1. Elevate the rear wheel by placing the
suitable stand under the engine.
2. Remove:
Left side cover
3. Loosen:
Locknut 1
4. Adjust:
Spring preload
By turning the adjuster 2.
NOTE:
Be sure to remove all dirt and mud from
around the locknut and adjuster before
adjustment.
The length of the spring (installed) changes
1.5 mm (0.06 in) per turn of the adjuster.
CAUTION:
Never attempt to turn the adjuster beyond
the maximum or minimum setting.Stiffer →Increase the spring preload.
(Turn the adjuster 2 in.)
Softer →Decrease the spring preload.
(Turn the adjuster 2 out.)
Spring length (installed) a:
Standard length Extent of adjustment
TT-R125E:
165 mm
(6.50 in)
TT-R125LWE:
160.5 mm
(6.32 in)TT-R125E:
155 ~ 175 mm
(6.10 ~ 6.89 in)
TT-R125LWE:
147.5 ~ 167.5 mm
(5.81 ~ 6.59 in)
REAR SHOCK ABSORBER ASSEMBLY INSPECTION/
REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT

4 - 21
ENGCAMSHAFT AND ROCKER ARMS
REMOVAL POINTS
Rocker arm shaft
1. Remove:
Rocker arm shafts
NOTE:
Use a slide hammer bolt 1 and weight 2 to
slide out the rocker arm shafts.
Small slide hammer set:
YU-1083-A
Slide hammer bolt:
90890-01085
Weight:
90890-01084
Camshaft
1. Remove:
Camshaft 1
Camshaft bearing 2
NOTE:
Screw in a suitable length of 8 mm bolt 3 into
the threaded end of the camshaft and pull out
the camshaft.
INSPECTION
Camshaft
1. Inspect:
Cam lobes
Pitting/scratches/blue discoloration →
Replace.
2. Measure:
Cam lobes length a and b
Out of specification → Replace.
Cam lobes length limit:
Intake:
a 25.851 mm (1.0178 in)
b 21.165 mm (0.8333 in)
Exhaust:
a 25.811 mm (1.0162 in)
b 21.020 mm (0.8276 in)

4 - 29
ENGVALVES AND VALVE SPRINGS
Install the valve into the cylinder head.
Turn the valve until the valve face and
valve seat are evenly polished, then clean
off all of the compound.
NOTE:
For best lapping results, lightly tap the valve
seat while rotating the valve back and forth
between your hands.
Apply a fine lapping compound to the
valve face and repeat the above steps.
NOTE:
After every lapping operation be sure to
clean off all of the compound from the valve
face and valve seat.
Apply Mechanic’s blueing dye (Dykem) to
the valve face.
Install the valve into the cylinder head.
Press the valve through the valve guide
and onto the valve seat to make a clear
pattern.
Measure the valve seat width again. If the
valve seat width is out of specification,
reface and re-lap the valve seat.
Valve spring
1. Measure:
Valve spring free length a
Out of specification → Replace.
Free length (valve spring):
Intake:
32.55 mm (1.28 in)
: 31.2 mm (1.23 in)
Exhaust:
32.55 mm (1.28 in)
: 31.2 mm (1.23 in)

4 - 30
ENGVALVES AND VALVE SPRINGS
2. Measure:
Compressed spring force a
Out of specification → Replace.
bInstalled length
3. Measure:
Spring tilt a
Out of specification → Replace.
Compressed spring force:
Intake:
14.0 ~ 16.1 kg at 25.6 mm
(30.86 ~ 35.49 lb at 1.01 in)
Exhaust:
14.0 ~ 16.1 kg at 25.6 mm
(30.86 ~ 35.49 lb at 1.01 in)
Spring tilt limit:
Intake:
2.5˚/1.4 mm (0.06 in)
Exhaust:
2.5˚/1.4 mm (0.06 in)
ASSEMBLY AND INSTALLATION
Valve
1. Apply:
Molybdenum disulfide oil
(onto the valve stem and valve stem
seal)
2. Install:
Valve spring seats 1
Valve stem seals 2
Valves 3
Valve springs 4
Valve spring retainers 5
NOTE:
Make sure that each valve is installed in its
original place.
Install the valve springs with the larger pitch
a facing upwards.
bSmaller pitch
New

4 - 44
ENGCLUTCH AND PRIMARY DRIVEN GEAR
EC484400
Clutch spring
1. Measure:
Clutch spring free length a
Out of specification → Replace springs
as a set.
Clutch spring free length:
33 mm (1.30 in)
: 31 mm (1.22 in)
EC484500
Friction plate
1. Measure:
Friction plate thickness
Out of specification → Replace friction
plate as a set.
Measure at all four points.
EC484600
Clutch plate
1. Measure:
Clutch plate warpage
Out of specification → Replace clutch
plate as a set.
Use a surface plate 1 and thickness
gauge 2.
Push lever
1. Inspect:
Push lever 1
Wear/damage → Replace.
Friction plate thickness:
2.92 ~ 3.08 mm
(0.115 ~ 0.121 in)
: 2.8 mm (0.110 in)
Warp limit:
0.2 mm (0.008 in)

5 - 35
CHASFRONT FORK
Damper rod holder:
YM-1300/90890-01294
T-handle:
YM-1326/90890-01326
3. Remove:
Oil seal 1
Using slotted-hand screwdriver.
CAUTION:
Take care not to scratch the outer tube.
EC554000
INSPECTION
Damper rod
1. Inspect:
Damper rod
Bend/damage → Replace damper rod.
CAUTION:
The front fork with a built-in piston rod has
a very sophisticated internal construction
and is particularly sensitive to foreign
material.
Use enough care not to allow any foreign
material to come in when the oil is replaced
or when the front fork is disassembled and
reassembled.
EC554400
Fork spring
1. Measure:
Fork spring free length a
Out of specification → Replace.
Fork spring free length:
Standard
TT-R125E:
327 mm (12.9 in)
TT-R125LWE:
453.6 mm
(17.86 in)TT-R125E:
322 mm (12.7 in)
TT-R125LWE:
448.6 mm
(17.66 in)

6 - 14
–+ELEC
5. Measure:
Brush length a
Out of specification → Replace.
Brush length wear limit:
3.5 mm (0.14 in)
6. Measure:
Brush spring force
Fatigue/out of specification → Replace
as a set.
Brush spring force:
5.52 ~ 8.28 N
(560 ~ 840 g, 19.8 ~ 29.7 oz)
ASSEMBLY
1. Install:
Brush spring 1
Brush 2
212
2. Install:
Armature assembly 1
Install while holding down the brush
using a thin screw driver.
CAUTION:
Be careful not to damage the brush during
installation.
ELECTRIC STARTING SYSTEM