Yamaha XT 125R 2005 Operating and installation instructions

IDM C144600300.fm
2005
XT 125R
XT 125X
SERVICE
INFORMATION

3
IDM C144600300.fm
WARNING
This Manual has been written by Yamaha Motor and is addressed to Yamaha vendors and their qualified
engineers. This Manual cannot cover any aspect of mechanical knowledge; therefore, anyone who will refer to this
manual is expected to have a basic knowledge of the mechanical skills required for servicing and repairing Yamaha
motorcycles. Repairing performed by unskilled personnel may cause motorcycles to be unserviceable and
dangerous.
Yamaha Motor is constantly searching for enhancing all its motorcycle models. Authorized Yamaha distributors will
be informed of substantial changes and improvements made to specifications or mounting procedures; these ones
will be stated in the following issues of this Manual, when required.
NOTE: The motorcycle model and specifications are subject to changes without prior notice.
IMPORTANT INFORMATION
Particularly important information is highlighted as follows:
The symbol of danger means CAUTION! BEWARE! YOUR SAFETY DEPENDS ON THIS!
The non-observance of WARNINGS can cause serious injury or the death of the
motorcyclist, of the people standing near the motorcycle or the repairer of the motorcycle.
A CAUTION notice implies particular care to be taken not to damage the motorcycle.
A NOTE contains important information for a better comprehension of the described
procedures.
WARNING:
CAUTION:
NOTE:

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IDM C144600300.fm
GRAPHIC SYMBOLS
Symbols to are drawn as tabs to indicate the
chapter number and its content.
General Information
Technical Specifications
Scheduled Servicing and Adjustment
Engine
Carburetion
Frame
Electrical System
Troubleshooting
Symbols to are used to identify technical
specifications stated in this Manual.
Repairing Possible with Engine in Place
Filling Up
Lubricant
Special Components
Tightening
Wear Limit, Distance
Engine RPM
Ω, V, A (to be measured with a tester)
Symbols to illustrated in the diagram indicate the
types of lubricant to be used and the greasing points.
Use Engine Oil
Use Oil for Spare Parts
Use Molybdenum-Bisulphide Oil
Use Grease for Bearings
Use Grease Made of Light Lithium Soap
Use Molybdenum-Bisulphide Grease
Symbols - illustrated in the diagram indicate where
to apply the high-resistance sealer and where to
install new Component Parts .
Apply High-Resistance Sealer (LOCTITE®)
Use a New Component Part
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IDM C144600300.fm
INDEX
GENERAL INFORMATION ......................................................................................................6
IDENTIFICATION OF THE MOTORCYCLE .........................................................................6
SPECIAL COMPONENTS ....................................................................................................7
TECHNICAL SPECIFICATIONS ..............................................................................................9
GENERAL FEATURES ........................................................................................................9
SERVICING TECHNICAL DATA ...........................................................................................12
ENGINE ..............................................................................................................................12
LUBRICATION DIAGRAMS ................................................................................................15
ENGINE TIGHTENING TORQUES ....................................................................................17
FRAME ...............................................................................................................................18
FRAME TIGHTENING TORQUES .....................................................................................20
ELECTRICAL SYSTEM ......................................................................................................21
WIRING ...................................................................................................................................24
WIRING (1) .........................................................................................................................24
WIRING (2) ......................................................................................................................... 26
SCHEDULED SERVICING AND ADJUSTMENT ...................................................................28
SCHEDULED MAINTENANCE AND GREASING...............................................................28
WIRING DIAGRAM ................................................................................................................30

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IDM C144600300.fm
GENERAL INFORMATION
GEN
INFO
GENERAL INFORMATION
IDENTIFICATION OF THE MOTORCYCLE
Serial Number of the Frame
The Serial Number of the frame is
marked on the metal tube of the
handlebar.
NOTE: The Serial Number of the
frame is used for the motorcycle
identification and registration.
Serial Number of the Engine
The Serial Number of the Engine is
marked on the right side of the
crankcase.
NOTE: The first three figures of this
Serial Number identify the
motorcycle model; the remaining
figures indicate the production
number of the unit.
NOTE: Technical specifications and
drawings can be changed without
prior notice.
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IDM-44600300300.tif
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IDM-44600300200.tif

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IDM C144600300.fm
GENERAL INFORMATION
GEN
INFO
SPECIAL COMPONENTS
The special components listed below are required for a complete and accurate tuning and assembly of the
motorcycle. The use of proper special instruments prevents damages caused by improper instruments or made-
up techniques.
When ordering a special component, please refer to the list below to avoid any mistake.
Component N. Description Picture
90890-01312 Fuel Indicator
The fuel indicator is used to measure the fuel level in the
carburettor float chamber.
90890-06760 Rev Counter
The rev counter is used to measure the engine RPM.
90890-04086/09 All-purpose Clutch Support
This support is used to lock the clutch when assembling
or disassembling the clutch locking nut.
90890-01701 Pulley Lock
The pulley lock is used to lock the secondary pulley.
90890-01862 Flywheel Puller
This is used to pull out the flywheel.
90890-01304 Pin Puller
The pin puller is used to pull out the piston pin.
90890-01135 Tool for Drive Shaft Remover
This tool is used to remove the drive shaft or to separate
the crankcase.

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IDM C144600300.fm
GENERAL INFORMATION
GEN
INFO
(*) Indications from Yamaha are required about the compatibility of the components above. If they are not compatible, ID codes and drawings
of new components are required. Otherwise, Yamaha should state which components are to be excluded from this Manual.
90890-01274 (1)
90890-01275 (2)
90890-01278 (3)
Tool for Drive Shaft Installation
Drive Shaft Pin
Adaptor (M12)
(*) 90890-01326 T-tool
The T-tool is used to hold the shock absorber rod when it
is removed or installed.
(*) 90890-01367
(*) 90890-01381
Fork Clamp
Fork Clamp Fitting
The fork clamp fitting is used to install the fork cross.
(*) 90890-01403 Nut Ring Wrench
This wrench is used to loosen and tighten the nut ring of
the handlebar.
90890-03112 Pocket Tester
The pocket tester is required to check the electrical
system.
Component N. Description Picture

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IDM C144600300.fm
TECHNICAL SPECIFICATIONS SPEC
TECHNICAL SPECIFICATIONS
GENERAL FEATURES
Model XT 125R XT 125X
Dimensions:
Overall Length 2110 mm 2040 mm
Overall Width 860 mm 860 mm
Overall Height 1130 mm 1090 mm
Saddle Height 860 mm 830 mm
Pitch 1340 mm 1340 mm
Min. Distance from the Ground 300 mm 271 mm
Min. Turning Radius 2100 mm 2016 mm
Net Weight:
Oil and Fuel Included 120 kg 120 kg
Engine:
Type of Engine: 4-stroke, air-cooling
Feeding System Carburettor
Cylinder Arrangement Tilted forward, single-cylinder
Displacement 123.7 cm3
Diameter per Stroke 54.0x54.0
Compression Ratio 10:1 ±0.5
Max. Power 7.3 kW / 8500 RPM
Max. Torque 9.5 N*m / 5500 RPM
Min. Speed 1600~1800 RPM
Starting System Electrical and manual starter
Lubrication System Yamaha Autolube
Oil Type or Grade:
Motor Oil YAMALUBE 4, SAE 10W30/SH or equivalent
Total Quantity 1.2 L
Scheduled Oil Change 1.0 L
Air Filter: Humid-element type
Fuel:
Type Unleaded
Fuel Tank:
Capacity 10 L
Low Fuel 2.0 L

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IDM C144600300.fm
TECHNICAL SPECIFICATIONS SPEC
Carburettor:
Type/Quantity VM20SS
Manufacturer MIKUNI
Spark Plugs:
Type CR7HSA
Manufacturer NGK
Distance between Electrodes 0.6 mm (0.0236 in)
Type of Clutch: Oil-bath, multiple disc
Gear:
Primary Step-down System Worm gear
Primary Step-down Ratio 68/20 (1/3,4)
Secondary Step-down Ratio Drive chain
Secondary Step-down Ratio 50/14 (3.5715) 48/14 (3.4286)
Type of Gear Continuous gear, 5-speed
Operation Left foot
Drive Ratio:
First Gear 14/37 (2.64)
Second Gear 18/32 (1.78)
Third Gear 19/25 (1.32)
Fourth Gear 22/23 (1.05)
Fifth Gear 24/21 (0.88)
Frame:
Type of Frame Semi double cradle Semi double cradle
Front Axle Angle 28° 26.7°
Angle Base 114.4 mm 78.33 mm
Tyres:
Type With inner tube With inner tube
Front 90/90-21 54S 100/80-17 52S
Rear 120/80-18 62S 130/70-17 62S
Pressure with Cold Wheels:
Front 0~90kg 1.8 bars (26.1 psi)
Rear 0~90kg 1.9 bars (27.6 psi)
Front 90~178kg 2.0 bars (29.0 psi)
Rear 90~178kg 2.1 bars (30.5 psi)
Model XT 125R XT 125X

11
IDM C144600300.fm
TECHNICAL SPECIFICATIONS SPEC
Brakes:
Type of Front Brake Disc brake with hydraulic drive
Front Brake Operation Right hand
Type of Rear Brake Disc brake with hydraulic drive
Rear Brake Operation Right foot
Suspensions:
Front Hydraulic fork
Rear Swinging arm with hydraulic shock absorber
Shock Absorbing System:
Front Coil spring / Oil damper
Rear Coil spring / Oil damper
Wheel Stroke:
Front Wheel Stroke 170 mm (6.69 in) 170 mm (6.69 in)
Rear Wheel Stroke 190 mm (7.48 in) 190 mm (7.48 in)
Electrical System:
Starting System CDI
Generator System Magnetic AC
Battery Capacity 12V-6.5Ah
Headlight: Bulb
Headlight Power:
Headlight 12V 35/35W
Rear Light/Stop Light 12V P21/5W
Front/Rear Indicators 12V 10Wx4
Plate Light 12V 5W
Dashboard Warning Light LED
Warning Lights:
"FUEL LEVEL" LED
"DIRECTION" LED
"NEUTRAL" LED
"HEADLIGHTS ON FULL BEAM" LED
"PARKING LIGHTS" LED
Amperage:
Main Fuse 10A
Model XT 125R XT 125X

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
SERVICING TECHNICAL DATA
ENGINE
Picture Description Standard Limit
Cylinder Head:
Planarity Error
The lines indicate the
points for the planarity
measures.
0.03 mm
Cylinder:
Hole size 54.00~54.020 mm -
Cylinder:
Hole size 54.00~54.020 mm
Piston:
Piston Diameter (D) 53.977~53.996 mm -
Measure Point (H) 4.5 mm -
Piston/Cylinder Clearance 0.020~0.028 mm 0.15 mm
Hole diameter (F) 15.002~15.013 mm -
Pin Diameter 14.991~15.000 mm -
Timing System:
Type of Drive Chain drive -
Timing Cams:
Inlet Cam Height (A) 25.881~25.981 mm 25.851 mm
Exhaust Cam Height (A) 25.841~25.941 mm 25.811 mm
Inlet Cam Width (B) 21.195~21.295 mm 21.165 mm
Exhaust Cam Width (B) 21.05~21.15 mm 21.02 mm
Inlet Cam Height (C) 4.391 mm -
Timing Shaft Eccentricity -0.03 mm
Compensators:
Bearing Inner Diameter 10.000~10.015 mm 10.03 mm
Bearing Outer Diameter 9.981~9.991 mm 9.95 mm
Timing Chain:
Type Bush chain/P -
Pitch per Link Number 6.35 x 88 -
Adjustment Automatic -
Valves, Housings and Guides:
Inlet Valve Clearance (Cold Operation) 0.08~0.12 mm -
Exhaust Valve Clearance (Cold
Operation) 0.10~0.14 mm -
Inlet Valve Diameter (A) 25.9~26.1 mm -
Exhaust Valve Diameter (A) 21.9~22.1 mm -
Inlet Valve Width (B) 1.1~3.0 mm -

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
Exhaust Valve Width (B) 1.7~2.8 mm -
Valve Housing Width (C) 0.9~1.1 mm 1.6 mm
Inlet Valve Thickness (D) 0.4~0.8 mm -
Exhaust Valve Thickness (D) 0.8~1.2 mm -
Diameter of Inlet Valve Stem 4.975~4.990 mm 4.950 mm
Diameter of Exhaust Valve Stem 4.960~4.975 mm 4.935 mm
Diameter of Inlet Valve Guides 5.000~5.012 mm 5.042 mm
Clearance of Inlet valve Guide/Stem 0.010~0.037 mm 0.08 mm
Clearance of Exhaust Valve Guide/Stem 0.025~0.052 mm 0.10 mm
Valve Stem Eccentricity -0.010 mm
Valve Springs:
Free Length 38.78 mm 37.0 mm
Spring Length when the Valve is
Closed 25.6 mm -
Compression 13.2~15.5 kgf
(132~155 N) -
Winding Direction (from top) Clockwise -
Upper Piston Ring:
Type Barrel -
Dimensions (BxT) 1.0x2.1 mm -
Distance between Ends (when installed) 0.15~0.30 mm 0.4 mm
Side Clearance 0.03~0.07 mm 0.12 mm
Intermediate Piston Ring:
Type Tap er -
Dimensions (BxT) 1.0x2.1 mm -
Distance between Ends (when installed) 0.15~0.30 mm 0.4 mm
Side Clearance 0.02~0.06 mm 0.12 mm
Lower Piston Ring:
Dimensions (BxT) 2.0x2.2 mm -
Distance between Ends (when installed) 0.2~0.7 mm -
Drive Shaft:
Crank Width (A) 46.95~47.00 mm -
Eccentricity (C) -0.03 mm
Side Clearance of Big End of the
Connecting Rod (D) 0.15~0.45 mm -
Side Clearance of Small End of the
Connecting Rod (E) -0.8 mm
Picture Description Standard Limit

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
Clutch:
Clutch Disc Thickness (conductors) 2.92~3.08 mm 2.80 mm
Quantity 5 pcs -
Clutch Disc Thickness (conduced) 1.05~1.35 mm 0.05 mm
Quantity 4 pcs -
Clutch Spring Free Length 31 mm -
Quantity 4 pcs -
Min. Free Length 29 mm -
Carburettor:
ID Mark 3D6 -
Main Jet #105 -
Main Air Jet 1.2 -
Jet Pin 5EJ9-2 -
Jet Needle N-7M(913) -
Min. Output f1.05 -
Min. Jet #12.5 -
Bypass 1.6 -
Adjusting Screw Rev 1 -
Valve Housing Dimensions 1.8 -
Starter Jet 22.5 -
Jet Power #60 -
Fuel Level 7.5 mm -
Float Height 18.9 mm -
Min. Speed 1600~1800 RPM -
Picture Description Standard Limit

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
LUBRICATION DIAGRAMS
IDM-44600300900.tif
Compensator Arm
(Suction)
Compensator Arm
(Exhaust)
Compensator
Shaft
Cam Shaft
Crankcase (right)
Clutch Lever
Oil Suction
Filter
Oil Pump
Centrifugal Filter
Motor Oil in
Crankcase
Motor Axis
Main Axis
Do not damage the crankcase surface to avoid oil leakage.
CAUTION:

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
IDM-44600301000.tif
Cam Shaft
Centrifugal Filter
Crankcase
Main Axis
Clutch
Cover (Right)
Chain Guard
(Right)
Cover (Left)
Motor Axis
Chain Guard
(Left)
To enhance performance,always use “Yamalube” oil.
CAUTION:
Cylinder Head
Cylinder

17
IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
ENGINE TIGHTENING TORQUES
Components To Be Tightened Type Q.ty Thread Tightening Torque Notes
Kg*m N*m
Cylinder Head Screw
Screw
4
2
M8
M6
2.2
1.0
22
10 Oil check
Plug -1M10 1.25 12.5
Cylinder Head Side Guard Screw 2M6 1.0 10
Valve Cap -2M45 1.75 17.5
Magnet Rotor Screw 1M12 7.0 70
Chain Guide Screw 1M6 1.0 10
Adjusting Screw Nut 2M5 0.75 7.5
Timing Chain Pinion Screw 1M8 2.0 20
Camshaft Locking Plate Screw 1M6 1.0 10
Plug (Turnbuckle) Plug 1M8 0.75 7.5
Turnbuckle Unit Screw 2M6 1.0 10
Oil Pump Screw 2M6 0.7 7
Drain Plug Screw 1M12 2.0 20
Manifold Screw 2M6 1.0 10
Carburettor/Manifold Clamp Screw 1M4 0.2 2
Carburettor/Air Filter Clamp Screw 1M4 0.2 2
Silencer Screw 2M6 1.0 10
Oil Sump Torque
Screw
Screw
Screw
2
7
1
M6
M6
M6
1.0
1.0
1.0
10
10
10
Flywheel Side Cap
Screw
Screw
Screw
4
2
1
M6
M6
M6
1.0
1.0
1.0
10
10
10
Clutch Side Cap
Screw
Screw
Screw
6
2
1
M6
M6
M6
1.0
1.0
1.0
10
10
10
Plate Screw 1M6 0.7 7
Ignition Stage Control Plug Screw 1M14 0.7 7
Main Plug Screw 1M32 0.7 7
Starting Pedal Crank Base Nut 1M12 5.0 50
Engine Pinion Nut 1M12 7.0 70
Disc Pusher Screw 4M5 0.6 6
Clutch Hub Nut 1M12 6.0 60
Clutch Disc Pusher Rod Nut 1M6 0.8 8With locking
washer
Locking Plate Screw 2M6 1.0 10
Engine Pinion Screw 2M8 1.0 10
Gear Indicator Lever Screw 1M6 1.0 10
Desmodronic Pulling Cam Screw 1M6 1.2 12
Pick-up Screw 2M6 1.0 10
Idling Light Sensor -1M10 0.4 4
Stator Screw 3M6 1.0 10
Oil Pressure Checkscrew Screw 1 - 0.7 7

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
FRAME
Detail Standard Limit
XT 125R XT 125X XT 125R XT 125X
Front Wheel:
Type Spoked wheel Spoked wheel
Rim Dimensions 21x1.85 17x2.50
Rim Material Aluminium Aluminium
Stroke 170 mm (6.69’’) 170 mm (6.69’’)
Max. Radial Clearance 1 mm 1 mm
Max. Side Clearance 0.5 mm 0.5 mm
Rear Wheel:
Type Spoked wheel Spoked wheel
Rim Dimensions 18x2.50 17x3.00
Rim Material Aluminium Aluminium
Stroke 190 mm (7.48") 190 mm (7.48”)
Max. Radial Clearance 1 mm (0.04") 1 mm (0.04")
Max. Side Clearance 0.5 mm (0.02") 0.5 mm (0.02")
Front Disc Brake:
Disc Dimensions 245.0x3.5 mm 260.0x3.5 mm
Inside Pad Lining Thickness 3 mm 3 mm 0.8 mm 0.8 mm
Inside Pad Lining Thickness 3 mm 3 mm 0.8 mm 0.8 mm
Pump Piston Diameter 11 mm 11 mm
Piston Pliers Diameter 32 mm 25 mm
Recommended Fluid DOT 4 DOT 4
Rear Disk Brake:
Disc Dimensions 218x3.5 mm
Inside Pad Lining Thickness 4 mm 1.0 mm
Inside Pad Lining Thickness 4 mm 1.0 mm
Pump Piston Diameter 12.7 mm
Piston Pliers Diameter 32 mm
Recommended Fluid DOT 4
Steering System:
Type of Steering System Conical roller bearing
Bearing Quantity 1 upper/1 lower

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IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
Front Suspension:
Fork Free Length 575 mm
Spring Stiffness K1 4.8 N/mm
Spring Stroke K1 (Packed Spring) 250 mm
Available Optional Spring NO
Recommended Oil SAE10
Quantity 285 cc/Rod
Level 180 mm (limit stop, with no spring)
Rear Suspension:
Type Swinging Arm
Rear Shock Absorber Compression 45 mm
Spring Free Length 163 mm
Spring Length when Installed 158 mm
Spring Preload Hard/Soft (5 mm)
Spring Stiffness (K) 17.7 daN/mm
Spring Stroke 55 mm
Available Optional Spring YES
Gas/Air Pressure Included 12.5±3 bars
Drive Chain:
Type/Manufacturer 428H G&G/DID 428H G&G/DID
Articulated Joint N. 128 126
Front Brake Lever/Rear Brake Pedal:
Front Brake Lever Clearance 2~5 mm
Brake Pedal Clearance 15 mm
Detail
Standard Limit
XT 125R XT 125X XT 125R XT 125X

20
IDM C144600300.fm
SERVICING TECHNICAL DATA SPEC
FRAME TIGHTENING TORQUES
Components To Be Tightened Type Q.ty Thread Tightening Torque Notes
kg*m N*m
Front Wheel Pin Screw 1M14x1.5 4.5 45
Front Wheel Pin Locking Screw 1M8x25 2.0 20
Front Brake Pliers Screw 2M8 3.0 30
Muffler Side Connection Screw 3M6 0.8 8
Engine Rear Connection Screw 2M8 2.3 23
Fork Pin Screw 1M14x1.5 6.0 60
Engine Front Connection Screw 2M8 2.3 23
Front Pump Clamp Screw 2M6 0.6 6
Rear Wheel Screw 1M14x1.5 8.5 85
Command Clamp Screw 2M6 0.3 3
Rear Shock Absorber Screw 2M10 4.5 45
Upper Cross Screw 2M8 1.95 19.5
Handlebar U-bolt Screw 4M8 2.15 21.5
Steering System Nut 1M25x1 3.0 30
Rear Frame Screw 4M8 2.0 20
Silencer Screw 1M8 2.3 23