2003 YAMAHA TTR125 warning

5 - 9
CHASFRONT WHEEL (TT-R125LW)
REMOVAL POINTS
EC513201
Wheel bearing (if necessary)
1. Remove:
Bearing 1
NOTE:
Remove the bearing using a general bearing
puller 2.
INSPECTION
EC514100
Wheel
1. Measure:
Wheel runout
Out of limit → Repair/replace.
2. Inspect:
Bearing
Rotate inner race with a finger.
Rough spot/seizure → Replace.
NOTE:
Replace the bearings, oil seal and wheel collar
as a set.
Wheel runout limit:
Radial 1: 2.0 mm (0.08 in)
Lateral 2: 2.0 mm (0.08 in)
EC514200
Wheel axle
1. Measure:
Wheel axle bends
Out of specification → Replace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
WARNING
Do not attempt to straighten a bent axle.
Wheel axle bending limit:
0.5 mm (0.020 in)

5 - 12
CHAS
FRONT BRAKE (TT-R125LW)
Extent of removal:1 Brake hose removal 2 Brake caliper removal
3 Brake master cylinder removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT BRAKE REMOVAL
Hold the machine by placing the
suitable stand under the engine.
Drain the brake fluid.
WARNING
Support the machine securely so there is nodanger of it falling over.
Refer to “REMOVAL POINTS”.
1 Brake hose holder 2
2 Union bolt 1
3 Brake hose 1
4 Joint 1
5 Brake caliper support bolt 1
6 Brake caliper 1 Refer to “REMOVAL POINTS”.
7 Brake lever 1
8 Brake master cylinder bracket 1
9Brake master cylinder
1
3
12
2
3
FRONT BRAKE (TT-R125LW)

5 - 13
CHASFRONT BRAKE (TT-R125LW)
BRAKE CALIPER AND BRAKE MASTER CYLINDER DISASSEMBLY
Extent of removal:1 Brake caliper disassembly2 Brake master cylinder disassembly
Extent of removal Order Part name Q’ty Remarks
Preparation for removalBRAKE CALIPER AND BRAKE
MASTER CYLINDER DISAS-
SEMBLY
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is no
danger of it falling over.
1Brake pad 2
2Brake caliper bracket 1
3Brake caliper piston 2 Refer to “REMOVAL POINTS”.
4Brake caliper dust seal 2
Refer to “REMOVAL POINTS”.
5Brake caliper piston seal 2
6Pin boot 1
7Sleeve boot 1
8Brake master cylinder cap 1
9Diaphragm 1
0Brake master cylinder boot 1
ACirclip 1
BWasher 1
CBrake master cylinder kit 1
2
1

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CHASFRONT BRAKE (TT-R125LW)
REMOVAL POINTS
Brake fluid
1. Remove:
Brake master cylinder cap 1
NOTE:
Do not remove the diaphragm.
2. Connect the transparent hose 2 to the
bleed screw 1 and place a suitable con-
tainer under its end.
3. Loosen the bleed screw and drain the
brake fluid while pulling in the lever.
CAUTION:
Do not reuse the drained brake fluid.
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled
fluid immediately.
Brake caliper
1. Remove:
Brake caliper 1
NOTE:
Turn the brake caliper counterclockwise and
pull out it from the guide pin 2 on the brake
caliper bracket.
Brake caliper piston
1. Remove:
Brake caliper piston
Use compressed air and proceed care-
fully.
WARNING
Cover piston with rag and use extreme
caution when expelling piston from cylin-
der.
Never attempt to pry out piston.
Brake caliper piston removal steps:
Insert a piece of rag into the brake caliper
to lock one brake caliper.
Carefully force the piston out of the brake
caliper cylinder with compressed air.

5 - 15
CHAS
Brake caliper piston seal kit
1. Remove:
Brake caliper dust seal 1
Brake caliper piston seal 2
NOTE:
Remove the brake caliper piston seals and
brake caliper dust seals by pushing them with
a finger.
CAUTION:
Never attempt to pry out brake caliper pis-
ton seals and brake caliper dust seals.
WARNING
Replace the brake caliper piston seals and
brake caliper dust seals whenever a brake
caliper is disassembled.
INSPECTION
Brake master cylinder
1. Inspect:
Brake master cylinder inner surface a
Wear/scratches → Replace brake mas-
ter cylinder assembly.
Stains → Clean.
WARNING
Use only new brake fluid.
2. Inspect:
Diaphragm 1
Crack/damage → Replace.
3. Inspect:
Brake master cylinder piston 1
Brake master cylinder cup 2
Wear/damage/score marks → Replace
brake master cylinder kit.
FRONT BRAKE (TT-R125LW)

5 - 16
CHAS
Brake caliper
1. Inspect:
Brake caliper cylinder inner surface a
Wear/score marks → Replace brake
caliper assembly.
2. Inspect:
Brake caliper piston 1
Wear/score marks → Replace brake
caliper piston assembly.
WARNING
Replace the brake caliper piston seals and
brake caliper dust seals 2 whenever a
brake caliper is disassembled.
3. Inspect:
Brake caliper bracket 1
Cracks/damage → Replace the brake
caliper assembly.
Guide pin 2
Rust/damage → Replace the brake cal-
iper assembly.
Sleeve boot 3
Pin boot 4
Wear/damage → Replace.
4. Inspect:
Brake caliper support bolt 1
Scorches/rust/damage → Replace.
Brake hose
1. Inspect:
Brake hose 1
Crack/damage → Replace.
FRONT BRAKE (TT-R125LW)

5 - 17
CHASFRONT BRAKE (TT-R125LW)
ASSEMBLY AND INSTALLATION
WARNING
All internal parts should be cleaned in
new brake fluid only.
Internal parts should be lubricated with
brake fluid when installed.
Replace the brake caliper piston seals
and brake caliper dust seals whenever a
brake caliper is disassembled.
Brake caliper piston
1. Clean:
Brake caliper
Brake caliper piston seal
Brake caliper dust seal
Brake caliper piston
Clean them with brake fluid.
2. Install:
Brake caliper piston seal 1
Brake caliper dust seal 2
WARNING
Always use new brake caliper piston seals
and brake caliper dust seals.
NOTE:
Fit the brake caliper piston seals and brake
caliper dust seals onto the slot on brake cali-
per correctly.
New
New
3. Install:
Brake caliper piston 1
NOTE:
Apply the brake fluid on the brake caliper pis-
ton wall.
CAUTION:
Install the brake caliper piston with its
shallow depressed side a facing the
brake caliper.
Never force to insert.
Brake caliper
1. Install:
Sleeve boot 1.
On brake caliper bracket 2.

5 - 19
CHASFRONT BRAKE (TT-R125LW)
2. Install:
Brake master cylinder cup (primary) 1
Brake master cylinder cup (secondary) 2
On brake master cylinder piston 3.
NOTE:
Apply the brake fluid on the brake master cyl-
inder cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
3. Install:
Spring 1
On brake master cylinder piston 2.
NOTE:
Install the spring at the smaller diameter side.
4. Install:
Brake master cylinder kit 1
Washer 2
Circlip 3
Brake master cylinder boot 4
On brake master cylinder 5
NOTE:
Apply the brake fluid on the brake master
cylinder kit.
When installing the circlip, use a long nose
circlip pliers.