2003 YAMAHA TTR125 light

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 - 31
ENG

VALVES AND VALVE SPRINGS
3. Install:

Valve cotters
1

NOTE:

While compressing the valve spring with a
valve spring compressor
2
, install the valve
cotters.
Valve spring compressor:
YM-4019/90890-04019
4. To secure the valve cotters onto the
valve stem, lightly tap the valve tip with a
piece of wood.
CAUTION:

Hitting the valve tip with excessive force
could damage the valve.

4 - 69
ENGCRANKCASE, CRANKSHAFT AND BALANCER
REMOVAL POINTS
Crankcase
1. Remove:
Bolt (crankcase)
Lead guide 1
Clutch cable holder 2
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove them.
2. Remove:
Right crankcase 1
Use the crankcase separating tool 2.
NOTE:
Fully tighten the tool holding bolts, but make
sure the tool body is parallel with the case. If
necessary, one screw may be backed out
slightly to level tool body.
As pressure is applied, alternately tap on the
front engine mounting boss and transmission
shafts.
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If one end “hangs
up”, take pressure off the push screw, re-
align, and start over. If the cases do not
separate, check for a remaining case screw
or fitting. Do not force.
Crankcase separating tool:
YU-1135-A/90890-01135

4 - 73
ENGCRANKCASE, CRANKSHAFT AND BALANCER
2. Install:
Balancer
NOTE:
Align the punched mark a on the balancer
drive gear with the punched mark b on the
balancer driven gear.
Crankcase
1. Apply:
Sealant
On the right crankcase 1.
NOTE:
Clean the contacting surface of crankcase (left
and right) before applying the sealant.
Quick gasket®:
ACC-QUICK-GS-KT
YAMAHA Bond No.1215:
90890-85505
2. Install:
Dowel pin 1
Right crankcase
On left crankcase.
NOTE:
Fit the right crankcase onto the left crank-
case. Tap lightly on the case with soft ham-
mer.
When installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).

4 - 76
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
REMOVAL POINTS
Transmission
1. Remove:
Main axle 1
Drive axle 2
NOTE:
Tap lightly on the transmission drive axle
with a soft hammer to remove.
Remove assembly carefully. Note the posi-
tion of each part. Pay particular attention to
the location and direction of shift forks.
EC4H4000
INSPECTION
EC4H4200
Gears
1. Inspect:
Matching dog a
Gear teeth b
Shift fork groove c
Wear/damage → Replace.
2. Check:
Gears movement
Unsmooth movement → Repair or
replace.
Push rod
1. Inspect:
Push rod 2 1
Wear/damage/bend → Replace.

5 - 4
CHAS

FRONT WHEEL AND FRONT BRAKE (TT-R125E)
Drum brake
1. Inspect:

Brake shoe lining surface
Glazed areas
→
Polish.
Use coarse sand paper.
NOTE:

After polishing, wipe the polished particles with
a cloth.
2. Measure:

Brake shoe lining thickness
a

Out of specification
→
Replace.
NOTE:

Replace the brake shoes and springs as a set
if either is worn to the limit.
Brake shoe lining thickness:
Standard
40 mm
(0.16 in)2.0 mm
(0.08 in)
3. Measure:

Brake drum inside diameter
a

Out of specification
→
Replace.
Brake drum inside diameter:
Standard
110 mm
(4.33 in)111 mm
(4.37 in)
4. Inspect:

Brake drum inner surface
Oil/scratches
→
Remove.
OilUse a rag soaked in lac-
quer thinner or a solvent.
ScratchesUse a emery cloth (lightly
and evenly polishing).

5 - 20
CHAS
Brake master cylinder
1. Install:
Brake master cylinder 1
Brake master cylinder bracket 2
Bolt (brake master cylinder bracket) 3
NOTE:
Install the brake master cylinder bracket so
that the arrow mark a face upward.
First tighten the bolts on the upper side of the
brake master cylinder bracket, and then
tighten the bolts on the lower side.
2. Install:
Brake lever 1
Spring 2
Bolt (brake lever) 3
Nut (brake lever) 4
NOTE:
Apply the lithium soap base grease on the
bolt and brake lever sliding surface.
Apply the molybdenum disulfide grease on
the tip of the adjuster bolt.
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)
U P2 1
3 3
a
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
Brake hose
1. Install:
Copper washer 1
Brake hose 2
Union bolt 3
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as show and lightly touches
the projection b on the brake caliper.
New
T R..26 Nm (2.6 m · kg, 19 ft · lb)
FRONT BRAKE (TT-R125LWE)

5 - 28
CHASREAR WHEEL AND REAR BRAKE
4. Inspect:
Brake drum inner surface.
Oil/scratches → Remove.
OilUse a rag soaked in lac-
quer thinner or a solvent.
ScratchesUse a emery cloth (lightly
and evenly polishing).
ASSEMBLY AND INSTALLATION
Brake shoe plate assembly
1. Install:
Brake camshaft 1
NOTE:
Apply the lithium soap base grease on the
brake camshaft.
2. Check:
Brake camshaft operation
Unsmooth operation → Repair.
3. Install:
Wear indicator plate 1
NOTE:
When installing the wear indicator plate to the
brake camshaft align the projection a on the
wear indicator plate with the slots b on the
brake camshaft.
4. Install:
Brake camshaft lever 1
NOTE:
Install the brake camshaft lever in relation to
the punch mark a as shown.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)