length YAMAHA TTR125 2002 User Guide

3 - 21
INSP
ADJ
DRIVE CHAIN INSPECTION
EC369002
DRIVE CHAIN INSPECTION
1. Remove:
lMaster link clip
lJoint 1
lDrive chain 2
2. Clean:
lDrive 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:
lDrive chain length (10 links) a
Out of specification ® Replace.
Drive chain length (10 links):
: 121.4 mm (4.78 in)
4. Check:
lDrive chain stiffness a
Clean and oil the chain and hold as
illustrated.
Stiff ® Replace drive chain.
5. Install:
lDrive chain 1
lJoint 2
lMaster link clip 3
CAUTION:
Be sure to install the master link clip to the
direction as shown.
aTurning direction
New

3 - 23
INSP
ADJ
FRONT FORK INSPECTION/
REAR SHOCK ABSORBER ASSEMBLY INSPECTION/
REAR SHOCK ABSORBER SPRING PRELOAD ADJUSTMENT
EC36C000
FRONT FORK INSPECTION
1. Inspect:
lFront fork smooth action
Operate the front brake and stroke the
front fork.
Unsmooth action/oil leakage ® Repair
or replace.
REAR SHOCK ABSORBER ASSEMBLY
INSPECTION
1. Inspect:
lSwingarm 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:
lLeft side cover
3. Loosen:
lLocknut 1
4. Adjust:
lSpring preload
By turning the adjuster 2.
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
165 mm
(6.50 in)155 ~ 175 mm
(6.10 ~ 6.89 in)

3 - 24
INSP
ADJ
TIRE PRESSURE CHECK
NOTE:
lBe sure to remove all dirt and mud from
around the locknut and adjuster before
adjustment.
lThe 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.
5. Tighten:
lLocknut
6. Install:
lLeft side cover
T R..42 Nm (4.2 m · kg, 30 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
EC36Q000
TIRE PRESSURE CHECK
1. Measure:
lTire pressure
Out of specification ® Adjust.
NOTE:
lCheck the tire while it is cold.
lLoose bead stoppers allow the tire to slip off
its position on the rim when the tire pressure
is low.
lA tilted tire valve stem indicates that the tire
slips off its position on the rim.
lIf the tire valve stem is found tilted, the tire is
considered to be slipping off its position. Cor-
rect the tire position.
Standard tire pressure:
100 kPa (1.00 kgf/cm2, 15 psi)

4 - 21
ENGCAMSHAFT AND ROCKER ARMS
REMOVAL POINTS
Rocker arm shaft
1. Remove:
lRocker 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:
lCamshaft 1
lCamshaft 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:
lCam lobes
Pitting/scratches/blue discoloration ®
Replace.
2. Measure:
lCam 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
lInstall the valve into the cylinder head.
lTurn 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.
lApply 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.
lApply Mechanic’s blueing dye (Dykem) to
the valve face.
lInstall the valve into the cylinder head.
lPress the valve through the valve guide
and onto the valve seat to make a clear
pattern.
lMeasure 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:
lValve 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:
lCompressed spring force a
Out of specification ® Replace.
bInstalled length
3. Measure:
lSpring 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:
lMolybdenum disulfide oil
(onto the valve stem and valve stem
seal)
2. Install:
lValve spring seats 1
lValve stem seals 2
lValves 3
lValve springs 4
lValve spring retainers 5
NOTE:
lMake sure that each valve is installed in its
original place.
lInstall 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:
lClutch 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:
lFriction plate thickness
Out of specification ® Replace friction
plate as a set.
Measure at all four points.
EC484600
Clutch plate
1. Measure:
lClutch plate warpage
Out of specification ® Replace clutch
plate as a set.
Use a surface plate 1 and thickness
gauge 2.
Push lever
1. Inspect:
lPush 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:
lOil seal 1
Using slotted-hand screwdriver.
CAUTION:
Take care not to scratch the outer tube.
EC554000
INSPECTION
Damper rod
1. Inspect:
lDamper 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:
lFork spring free length a
Out of specification ® Replace.
Fork spring free length:
Standard
TT-R125: 327 mm
(12.9 in)
TT-R125LW: 339 mm
(13.3 in)TT-R125: 322 mm
(12.7 in)
TT-R125LW: 334 mm
(13.1 in)