KTM 125 SX 2023 Owner's Manual
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KTM 125 SX 2023 Owner's Manual

KTM 125 SX 2023 Owner's Manual

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OWNER'S MANUAL
2023
125 SX
125 XC
Art. no. 3214638en

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Summary of Contents for KTM 125 SX 2023

  • Page 1 OWNER'S MANUAL 2023 125 SX 125 XC Art. no. 3214638en...
  • Page 3 KTM accepts no liability for delivery options, deviations from fig- ures and descriptions, misprints, and other errors. The models portrayed partly contain special equipment that does not belong to the regular scope of supply.

  • Page 4: Table Of Contents

    TABLE OF CONTENTS 6.15 Foot brake lever ....... 20 TABLE OF CONTENTS MEANS OF REPRESENTATION ...... 5 6.16 Plug-in stand (125 SX EU) ....20 Symbols used ........5 6.17 Side stand (125 XC US) ....21 Formats used........5 PREPARING FOR USE.........
  • Page 5 TABLE OF CONTENTS 10.9 Adjusting the spring preload of the 11.32 Removing the main silencer ....67 shock absorber ......40 11.33 Installing the main silencer....67 10.10 Adjusting the riding sag ....41 11.34 Changing the glass fiber yarn filling 10.11 Air suspension XACT ......
  • Page 6 TABLE OF CONTENTS 14 COOLING SYSTEM ........99 23.3.2 Coolant ........131 23.3.3 Fuel ......... 131 14.1 Cooling system ........ 99 23.4 Chassis ......... 131 14.2 Checking the antifreeze and coolant 23.5 Electrical system......132 level ..........99 23.6 Tires ..........132 14.3 Checking the coolant level ....

  • Page 7: Means Of Representation 1

    Indicates work that requires expert knowledge and technical understanding. In the interest of your own safety, have these jobs performed by an authorized KTM workshop! Your motorcycle will be cared for there to the highest degree by specially trained experts using the special tools required.

  • Page 8: Safety Advice

    2 SAFETY ADVICE Use definition – intended use (125 SX EU) This vehicle has been designed and built to withstand the normal stresses and strains of racing. This vehicle complies with the currently valid regulations and categories of the top international motorsports organizations. Info Only operate this vehicle in closed-off areas remote from public road traffic.

  • Page 9: Tampering Warning

    Wear appropriate protective clothing such as helmet, boots, gloves as well as trousers and a jacket with protectors on all rides. – Always wear protective clothing that is in good condition and meets the legal regulations. In the interest of your own safety, KTM recommends that you only operate the vehicle while wearing protective clothing.

  • Page 10: Work Rules

    The Owner's Manual can be downloaded several times using the QR code or the link on the delivery certificate. The Owner's Manual is also available for download from your authorized KTM dealer and on the KTM website. A printed copy can also be ordered from your authorized KTM dealer.

  • Page 11: Important Notes 3

    Manufacturer warranty, implied warranty The work prescribed in the service schedule must only be carried out in an authorized KTM workshop and con- firmed in the KTM Dealer.net, as otherwise all warranty claims will be void. Damage or secondary damage caused by tampering with and/or conversions on the vehicle are not covered by the manufacturer warranty.

  • Page 12: View Of Vehicle

    4 VIEW OF VEHICLE View of vehicle, front left (example) S05533-10 Hand brake lever ( p. 14) Clutch lever ( p. 14) Air filter box cover Engine number ( p. 12) Shift lever ( p. 20)

  • Page 13: View Of Vehicle, Rear Right (Example)

    VIEW OF VEHICLE 4 View of vehicle, rear right (example) S05534-10 Shock absorber compression adjuster Combination switch ( p. 16) Stop button ( p. 15) Start button ( p. 16) Throttle grip ( p. 15) Fork compression adjuster Vehicle identification number ( p.

  • Page 14: Serial Numbers

    5 SERIAL NUMBERS Vehicle identification number The vehicle identification number is stamped on the right side of the steering head. 401945-10 Type label The type label is fixed to the front of the steering head. 401946-10 Engine number Engine number is embossed on the left side of the engine above the engine sprocket.

  • Page 15: Shock Absorber Article Number

    SERIAL NUMBERS 5 Shock absorber article number Shock absorber article number is stamped on the top of the shock absorber above the adjusting ring towards the engine side. 401948-10...

  • Page 16: Controls

    6 CONTROLS Clutch lever (125 SX EU) Clutch lever is fitted on the handlebar on the left. The clutch is activated hydraulically and adjusts itself auto- matically. S05507-10 (125 XC US) Clutch lever is fitted on the handlebar on the left. The clutch is activated hydraulically and adjusts itself auto- matically.

  • Page 17: Throttle Grip

    CONTROLS 6 Throttle grip (125 SX EU) The throttle grip is fitted on the right side of the handle- bar. S05509-11 (125 XC US) The throttle grip is fitted on the right side of the handle- bar. S05510-11 Stop button (125 SX EU) The stop button is located on the right side of the handle-...

  • Page 18: Start Button

    6 CONTROLS Start button (125 SX EU) Start button is fitted on the right side of the handlebar. S05511-11 (125 XC US) Start button is fitted on the right side of the handlebar. Possible states • The start button is in the basic position is pressed –...

  • Page 19: Overview Of Indicator Lights (125 Xc Us)

    CONTROLS 6 Overview of indicator lights (125 XC US) Possible states Malfunction indicator lamp lights up/flashes orange – The OBD has detected a malfunction in the vehicle electronics. lights up white – Lean mapping is Indicator lamp activated. This mapping is recommended for firm/hard surfaces.

  • Page 20: Closing The Fuel Tank Filler Cap

    6 CONTROLS Warning Danger of poisoning Fuel is harmful to health. – Avoid skin, eye and clothing contact with fuel. – Immediately consult a doctor if you swallow fuel. – Do not inhale fuel vapors. – Rinse the affected area immediately with plenty of water in the event of contact with the skin. –...

  • Page 21: Cold Start Button

    CONTROLS 6 (125 XC US) – Mount filler cap and turn it clockwise until the release button engages. Info Route fuel tank breather hose without kinks. S05374-11 6.12 Cold start button The cold start button is fitted to the bottom of the throttle valve body.

  • Page 22: Shift Lever

    6 CONTROLS 6.14 Shift lever Shift lever is mounted on the left of the engine. 401950-10 The gear positions can be seen in the figure. The neutral or idle position is between the first and second gears. 401950-11 6.15 Foot brake lever Foot brake lever is located in front of the right footrest.

  • Page 23: Side Stand (125 Xc Us)

    CONTROLS 6 6.17 Side stand (125 XC US) The side stand is located on the left of the vehicle. 401943-10 The side stand is used for parking the motorcycle. Info When you are riding, side stand must be folded up and secured with rubber strap 401944-10...

  • Page 24: Preparing For Use

    When using the motorcycle, remember that others may be disturbed by excessive noise. – Ensure that the pre-sales inspection work has been carried out by an authorized KTM workshop. You will receive a delivery certificate when the vehicle is handed over.

  • Page 25: Running In The Engine

    PREPARING FOR USE 7 – Adjust the basic position of the foot brake lever. p. 87) – Adjust the basic position of the shift lever. p. 116) – Get used to the handling characteristic of the motorcycle on suitable terrain before undertaking a more chal- lenging ride.

  • Page 26: Starting Power Of Lithium-Ion Batteries At Low Temperatures

    7 PREPARING FOR USE Starting power of lithium-ion batteries at low temperatures Lithium-ion batteries are far lighter than lead batteries, have a low self-discharge rate, and have more starting power at temperatures over 15 °C (60 °F). At low temperatures, however, the starting power of lithium-ion batteries drops to below that of lead batter- ies.

  • Page 27: Preparing The Vehicle For Rides On Dry Sand

    Preparing the vehicle for rides on dry sand – Mount the air filter dust cover. Air filter dust cover (A46006920000) Info Observe the fitting instructions for KTM PowerParts. F03669-01 – Mount the air filter sand cover. Air filter sand cover (A46006922000) Info Observe the fitting instructions for KTM PowerParts.

  • Page 28: Preparing The Vehicle For Rides On Wet And Muddy Circuits

    Preparing the vehicle for rides on wet and muddy circuits – Mount the air filter rain cover. Air filter rain cover (A46006921000) Info Observe the fitting instructions for KTM PowerParts. F03668-01 – Mount the steel sprocket. – Clean the motorcycle. ( p.

  • Page 29: Preparing The Vehicle For Low Temperatures Or Snow

    PREPARING FOR USE 7 Preparing the vehicle for low temperatures or snow – Mount the air filter rain cover. Air filter rain cover (A46006921000) Info Observe the fitting instructions for KTM PowerParts. F03668-01...

  • Page 30: Riding Instructions

    8 RIDING INSTRUCTIONS Checks and maintenance measures when preparing for use Info Before every trip, check the condition of the vehicle and ensure that it is safe to operate. The vehicle must be in perfect technical condition when it is being operated. –...

  • Page 31: Starting Off

    RIDING INSTRUCTIONS 8 (125 SX EU) – Remove plug-in stand H02629-10 (125 XC US) – Take the motorcycle off side stand and secure the side stand with rubber strap – Shift the transmission into neutral. Condition Ambient temperature: < 20 °C (< 68 °F) –...

  • Page 32: Shifting, Riding

    Danger of accidents A spongy pressure point on the front or rear brake reduces braking efficiency. – Check the brake system and do not continue riding until the problem is eliminated. (Your authorized KTM workshop will be glad to help.) Warning Danger of accidents Moisture and dirt impair the brake system.

  • Page 33: Stopping, Parking

    RIDING INSTRUCTIONS 8 – Use the braking effect of the engine on long downhill stretches. Shift back one or two gears, but do not over- rev the engine when doing so. This means that significantly less braking is required and the brake system does not overheat.

  • Page 34: Refueling

    8 RIDING INSTRUCTIONS (125 SX EU) – Switch off the engine. – Mount plug-in stand on the fork legs. Plug-in stand (A46029094000) Info The plug-in stand is included. Make sure the brake line runs in front of the plug-in stand and does not become wedged. H02628-01 –...
  • Page 35 RIDING INSTRUCTIONS 8 – Fill the fuel tank with fuel up to measurement Guideline 35 mm (1.38 in) Measurement of Total fuel tank 7.2 l Super unleaded capacity, approx. (1.9 US gal) (98 octane) mixed (125 SX EU) with 2-stroke engine oil (1:40) p.

  • Page 36: Service Schedule

    Individual service intervals and scopes may change in the course of technical developments. The most up-to-date service schedule can always be found on KTM Dealer.net. Your authorized KTM dealer will be happy to advise you.
  • Page 37 ● ● Take a test ride. ○ ● ● ● ● Read out the fault memory after the test ride using the KTM diagnostics tool. ○ ● ● ● ● Make a service entry in KTM Dealer.net. ○ One-time interval ●...

  • Page 38: 10 Tuning The Chassis

    The shock absorber is filled with highly compressed nitrogen. – Please follow the description provided. (Your authorized KTM workshop will be glad to help.) Info The effect of the low-speed compression adjuster can be seen in slow to normal compression of the shock...

  • Page 39: Adjusting The High-Speed Compression Damping Of The Shock Absorber

    The shock absorber is filled with highly compressed nitrogen. – Please follow the description provided. (Your authorized KTM workshop will be glad to help.) Info The effect of the high speed compression adjuster can be seen in the fast compression of the shock absorber.

  • Page 40: Adjusting The Rebound Damping Of The Shock Absorber

    Risk of injury Parts of the shock absorber will move around if the shock absorber is detached incorrectly. The shock absorber is filled with highly compressed nitrogen. – Please follow the description provided. (Your authorized KTM workshop will be glad to help.) – Turn adjuster clockwise up to the last perceptible click.

  • Page 41: Checking The Static Sag Of The Shock Absorber

    TUNING THE CHASSIS 10 Finishing work – Remove the motorcycle from the lift stand. ( p. 48) 10.7 Checking the static sag of the shock absorber – Measure dimension of rear wheel unloaded. ( p. 38) – Hold the motorcycle upright with aid of an assistant. –...

  • Page 42: Adjusting The Spring Preload Of The Shock Absorber

    The shock absorber is filled with highly compressed nitrogen. – Please follow the description provided. (Your authorized KTM workshop will be glad to help.) Info Before changing the spring preload, make a note of the present setting, e.g., by measuring the spring length.

  • Page 43: Adjusting The Riding Sag

    TUNING THE CHASSIS 10 – Remove the motorcycle from the lift stand. ( p. 48) 10.10 Adjusting the riding sag Preparatory work – Raise the motorcycle with a lift stand. ( p. 48) – Remove the frame protector. ( p. 61) –...

  • Page 44: Air Suspension Xact

    10 TUNING THE CHASSIS 10.11 Air suspension XACT Air suspension WP XACT is used in the fork. In this system, the suspension is located in the left fork leg and damping in the right fork leg. As fork springs are no longer required, a significant weight advantage is achieved when compared to conventional forks.

  • Page 45: Adjusting The Fork Air Pressure

    A little air escapes from the fork leg when connecting. Info This is due to the volume of the hose and not due to a defect in the fork airpump or the fork. Read the accompanying KTM PowerParts instructions. – Adjust the air pressure as specified. Guideline Air pressure (125 SX EU) 8.5 bar (123 psi)

  • Page 46: Adjusting The Compression Damping Of The Fork

    10 TUNING THE CHASSIS When disconnecting, excess pressure will escape from the hose – the fork leg itself does not lose any air. The fork airpump indicator switches off automatically after 80 seconds. – Mount the protection cap. Info Only mount the protection cap by hand. Finishing work –...

  • Page 47: Handlebar Position

    TUNING THE CHASSIS 10 – Turn adjusting screw clockwise all the way. Info Adjusting screw is located at the lower end of the right fork leg. – Turn counterclockwise by the number of clicks corresponding to the fork type. Guideline F03633-10 Rebound damping (125 SX EU) Comfort...

  • Page 48: Adjusting The Handlebar Position

    10 TUNING THE CHASSIS 10.17 Adjusting the handlebar position Warning Danger of accidents A repaired handlebar poses a safety risk. If the handlebar is bent or straightened, the material becomes fatigued. The handlebar may break as a result. – Change the handlebar if the handlebar is damaged or bent. Info The handlebar can be mounted rigidly or on a rubber bearing.
  • Page 49 TUNING THE CHASSIS 10 Adjusting the handlebar position with the handlebar clamp – Place the handlebar support in the required position. Info The handlebar support is longer and higher on one side. – Mount and tighten the screws with the bushings Guideline Screw, handle- 40 Nm (29.5 lbf ft)

  • Page 50: 11 Service Work On The Chassis

    11 SERVICE WORK ON THE CHASSIS 11.1 Raising the motorcycle with a lift stand Note Material damage The vehicle may be damaged by incorrect procedure when parking. Significant damage may be caused if the vehicle rolls away or falls over. The components for parking the vehicle are designed only for the weight of the vehicle. –...

  • Page 51: Bleeding The Fork Legs

    SERVICE WORK ON THE CHASSIS 11 11.3 Bleeding the fork legs Preparatory work – Raise the motorcycle with a lift stand. ( p. 48) Main work – Release bleeder screws Any excess pressure escapes from the interior of the fork. –...

  • Page 52: Removing The Fork Protector

    11 SERVICE WORK ON THE CHASSIS 11.5 Removing the fork protector – Remove screws on the left fork leg. Take off the clamp. – Remove screws on the left fork leg. Take off the left fork protector. – Remove screws on the right fork leg.

  • Page 53: Installing The Fork Legs

    SERVICE WORK ON THE CHASSIS 11 11.8 Installing the fork legs Main work – Position the fork legs. Air bleeder screw of the right fork leg is positioned to the front. Valve of the left fork leg faces the front. Info Grooves are milled into the side of the upper end of the fork legs.

  • Page 54: Installing The Lower Triple Clamp

    11 SERVICE WORK ON THE CHASSIS Main work – Remove screw . Detach the wiring harness. – Remove screw – Remove screw – Take off the upper triple clamp with the handlebar and place to one side. Info Cover the components to protect them against damage. S05332-10 Do not kink the cables or lines.
  • Page 55 SERVICE WORK ON THE CHASSIS 11 – Position the fork legs. Air bleeder screw of the right fork leg is positioned to the front. Valve of the left fork leg faces the front. Info Grooves are milled into the side of the upper end of the fork legs.

  • Page 56: Checking Steering Head Bearing Play

    Danger of accidents Incorrect steering head bearing play impairs the handling characteristic and dam- ages components. – Correct incorrect steering head bearing play immediately. (Your authorized KTM workshop will be glad to help.) Info If the vehicle is operated for a lengthy period with play in the steering head bearing, the bearings and the bearing seats in the frame can become damaged over time.

  • Page 57: Adjusting Steering Head Bearing Play

    SERVICE WORK ON THE CHASSIS 11 Finishing work – Remove the motorcycle from the lift stand. ( p. 48) 11.12 Adjusting steering head bearing play Preparatory work – Raise the motorcycle with a lift stand. ( p. 48) – Remove the handlebar cushion. Main work –...

  • Page 58: Removing The Start Number Plate

    11 SERVICE WORK ON THE CHASSIS 11.14 Removing the start number plate – Remove screw – Unhook the start number plate from the brake line and remove S05336-10 11.15 Installing the start number plate – Position the brake line in holders on the start number plate.

  • Page 59: Installing The Front Fender

    SERVICE WORK ON THE CHASSIS 11 11.17 Installing the front fender Main work – Position the front fender. Mount and tighten screws Guideline Screw, fender 12 Nm (8.9 lbf ft) S05339-10 Finishing work – Install the start number plate. ( p.

  • Page 60: Installing The Shock Absorber

    11 SERVICE WORK ON THE CHASSIS – Remove connecting link of the chain. – Take off the chain. Info Cover the components to protect them against damage. S05386-01 – Remove nut and the swingarm pivot. – Push the link fork back and secure it against falling over. S05538-10 –...
  • Page 61 SERVICE WORK ON THE CHASSIS 11 – Mount the chain. – Connect the chain with connecting link Guideline The closed side of the chain joint lock must face in the direction of travel. S05387-11 – Position the foot brake cylinder. Push rod engages in the foot brake cylinder.

  • Page 62: Removing The Seat

    11 SERVICE WORK ON THE CHASSIS 11.20 Removing the seat – Remove screw S05350-10 – Raise seat, pull it toward the fuel tank and take it off. S05493-10 11.21 Mounting the seat – Attach the seat to the collar bushings at the front and simulta- neously push it back.

  • Page 63: Removing The Frame Protector

    SERVICE WORK ON THE CHASSIS 11 11.22 Removing the frame protector – Remove the cable ties. – Remove screws with the bushings. – Take off the left frame protector. – Push the right frame protector to the front and take off at the bottom.

  • Page 64: Installing The Engine Guard (125 Xc Us)

    11 SERVICE WORK ON THE CHASSIS 11.25 Installing the engine guard (125 XC US) – Position the engine guard on the frame. – Mount screws , but do not tighten yet. Guideline Remaining screws, 10 Nm (7.4 lbf ft) chassis –...

  • Page 65: Installing The Air Filter Box Cover

    SERVICE WORK ON THE CHASSIS 11 11.27 Installing the air filter box cover (125 SX EU) Condition The air filter box cover is secured. – Insert the air filter box cover in area and clip it into area S05542-10 – Mount and tighten screw Guideline Screw, air filter...
  • Page 66 11 SERVICE WORK ON THE CHASSIS (125 XC US) Condition The air filter box cover is secured. – Insert the air filter box cover in area and clip it into area S05542-10 – Mount and tighten screw Guideline Screw, air filter EJOT PT ®...

  • Page 67: Removing The Air Filter

    SERVICE WORK ON THE CHASSIS 11 11.28 Removing the air filter Note Engine damage Unfiltered intake air has a negative effect on the service life of the engine. Dust and dirt will enter the engine without an air filter. – Only operate the vehicle if it is equipped with an air filter. Note Environmental hazard Hazardous substances cause environmental damage.

  • Page 68: Installing The Air Filter

    11 SERVICE WORK ON THE CHASSIS Finishing work – Install the air filter. p. 66) – Install the air filter box cover. ( p. 63) 11.30 Installing the air filter Main work – Mount the clean air filter on the air filter support. Info The marking on the air filter support must face upwards.

  • Page 69: Preparing Air Filter Box Cover For Securing

    SERVICE WORK ON THE CHASSIS 11 11.31 Preparing air filter box cover for securing Preparatory work – Remove the air filter box cover. ( p. 62) Main work – Drill a hole at marking Guideline Diameter 6 mm (0.24 in) F03679-10 Finishing work –...

  • Page 70: Changing The Glass Fiber Yarn Filling In The Main Silencer

    11 SERVICE WORK ON THE CHASSIS 11.34 Changing the glass fiber yarn filling in the main silencer Warning Danger of burns The exhaust system gets very hot when the vehicle is driven. – Allow the exhaust system to cool down before performing any work on the vehicle. Info Over time, the fibers of the rock wool escape into the air, and the main silencer “burns out”.
  • Page 71 SERVICE WORK ON THE CHASSIS 11 Warning Danger of poisoning Fuel is harmful to health. – Avoid skin, eye and clothing contact with fuel. – Immediately consult a doctor if you swallow fuel. – Do not inhale fuel vapors. – Rinse the affected area immediately with plenty of water in the event of contact with the skin. –...

  • Page 72: Installing The Fuel Tank

    11 SERVICE WORK ON THE CHASSIS – Pull both spoilers laterally off the radiator and lift off the fuel tank. S05361-10 11.36 Installing the fuel tank Danger Fire hazard Fuel is highly flammable. The fuel in the fuel tank expands when warm and can escape if overfilled. –...

  • Page 73: Checking The Chain For Dirt

    SERVICE WORK ON THE CHASSIS 11 – Mount and tighten screw with the rubber bushing. Guideline Remaining screws, 10 Nm (7.4 lbf ft) chassis S05377-11 – Plug in fuel pump connector – Remove the wash cap set and thoroughly clean the quick release coupling using compressed air.

  • Page 74: Checking The Chain Tension

    11 SERVICE WORK ON THE CHASSIS Note Environmental hazard Hazardous substances cause environmental damage. – Dispose of oils, grease, filters, fuel, cleaning agents, brake fluid, etc., correctly and in compliance with the applicable regulations. Info The service life of the chain depends largely on its maintenance. Preparatory work –...

  • Page 75: Adjusting The Chain Tension

    SERVICE WORK ON THE CHASSIS 11 Finishing work – Remove the motorcycle from the lift stand. ( p. 48) 11.40 Adjusting the chain tension Warning Danger of accidents Incorrect chain tension damages components and results in accidents. If the chain is tensioned too much, the chain, engine sprocket, rear sprocket, transmission and rear wheel bearings wear more quickly.

  • Page 76: Checking The Chain, Rear Sprocket, Engine Sprocket, And Chain Guide

    11 SERVICE WORK ON THE CHASSIS 11.41 Checking the chain, rear sprocket, engine sprocket, and chain guide Preparatory work – Raise the motorcycle with a lift stand. ( p. 48) Main work – Shift the transmission into neutral. – Check the chain, rear sprocket, and engine sprocket for wear. »...
  • Page 77 SERVICE WORK ON THE CHASSIS 11 – Check the chain sliding guard for wear. » If the lower edge of the chain pins is in line with, or below, the chain sliding guard: – Change the chain sliding guard. – Check that the chain sliding guard is firmly seated.

  • Page 78: Checking The Frame

    11 SERVICE WORK ON THE CHASSIS – Check that the chain guide is firmly seated. » If the chain guide is loose: – Tighten the screws on the chain guide. Guideline Remaining screws, 10 Nm chassis (7.4 lbf ft) Remaining nuts, 10 Nm chassis (7.4 lbf ft)

  • Page 79: Checking The Rubber Grip

    SERVICE WORK ON THE CHASSIS 11 Main work – Check the throttle cable routing. Both throttle cables must be routed, side by side, on the back of the handlebars, above the fuel tank bracket on the right of the frame to the throttle valve body. The throttle cable must be secured on the fuel tank bracket with a rub- ber strap.

  • Page 80: Adjusting The Basic Position Of The Clutch Lever

    11 SERVICE WORK ON THE CHASSIS 11.46 Adjusting the basic position of the clutch lever – Adjust the basic position of the clutch lever to your hand size by turning adjusting screw Info Turn the adjusting screw counterclockwise to decrease the distance between the clutch lever and the handle- bar.

  • Page 81: Changing The Hydraulic Clutch Fluid

    SERVICE WORK ON THE CHASSIS 11 Info Clean up overflowed or spilled brake fluid immediately with water. 11.48 Changing the hydraulic clutch fluid Warning Skin irritation Brake fluid causes skin irritation. – Keep brake fluid out of the reach of children. –...
  • Page 82 11 SERVICE WORK ON THE CHASSIS – Now press the fluid into the system until it emerges from hole of the master cylinder without bubbles. – Occasionally extract the fluid from the master cylinder reser- voir to prevent overflowing. – Remove the bleeding syringe.

  • Page 83: Brake System 12

    Do not make any adjustments while riding. 12.3 Checking the brake discs Warning Danger of accidents Worn-out brake discs reduce the braking effect. – Make sure that worn-out brake discs are replaced immediately. (Your authorized KTM workshop will be glad to help.)

  • Page 84: Checking The Front Brake Fluid Level

    Danger of accidents Old brake fluid reduces the braking effect. – Make sure that brake fluid for the front and rear brake is changed in accordance with the service schedule. (Your authorized KTM workshop will be glad to help.) Preparatory work –...

  • Page 85: Adding Front Brake Fluid

    Danger of accidents Old brake fluid reduces the braking effect. – Make sure that brake fluid for the front and rear brake is changed in accordance with the service schedule. (Your authorized KTM workshop will be glad to help.) Note Environmental hazard Hazardous substances cause environmental damage.

  • Page 86: Checking That The Brake Linings Of The Front Brake Are Secured

    Checking that the brake linings of the front brake are secured Warning Danger of accidents Worn-out brake linings reduce the braking effect. – Ensure that worn-out brake linings are replaced immediately. (Your authorized KTM workshop will be glad to help.) – Check the brake linings for lining thickness ≥...

  • Page 87: Changing The Brake Linings Of The Front Brake

    Changing the brake linings of the front brake Warning Danger of accidents Incorrect servicing will cause the brake system to fail. – Ensure that service work and repairs are performed professionally. (Your authorized KTM workshop will be glad to help.) Warning Skin irritation Brake fluid causes skin irritation.
  • Page 88 12 BRAKE SYSTEM – Remove screws – Press back the brake linings by slightly tilting the brake caliper laterally on the brake disc. Carefully pull the brake caliper up and off the brake disc. – Press the brake piston back into the basic position and ensure that brake fluid does not flow out of the brake fluid reservoir;...

  • Page 89: Checking The Free Travel Of Foot Brake Lever

    BRAKE SYSTEM 12 – Add brake fluid up to level Guideline 5 mm (0.2 in) Level (brake fluid level below reservoir rim) Brake fluid DOT 4 / DOT 5.1 ( p. 138) – Position cover with membrane – Mount and tighten screws Info Use water to immediately clean up any brake fluid that has overflowed or spilled.

  • Page 90: Checking The Rear Brake Fluid Level

    Danger of accidents Old brake fluid reduces the braking effect. – Make sure that brake fluid for the front and rear brake is changed in accordance with the service schedule. (Your authorized KTM workshop will be glad to help.) Preparatory work –...

  • Page 91: Adding Rear Brake Fluid

    Danger of accidents Old brake fluid reduces the braking effect. – Make sure that brake fluid for the front and rear brake is changed in accordance with the service schedule. (Your authorized KTM workshop will be glad to help.) Note Environmental hazard Hazardous substances cause environmental damage.

  • Page 92: Checking That The Brake Linings Of The Rear Brake Are Secured

    Checking that the brake linings of the rear brake are secured Warning Danger of accidents Worn-out brake linings reduce the braking effect. – Ensure that worn-out brake linings are replaced immediately. (Your authorized KTM workshop will be glad to help.) – Check the brake linings for lining thickness ≥...
  • Page 93 Danger of accidents Brake linings which have not been approved alter the braking efficiency. Not all brake linings are tested and approved for KTM motorcycles. The structure and friction coefficient of the brake linings, and thus their brake power, may vary greatly from that of original brake linings.
  • Page 94 12 BRAKE SYSTEM Main work – Stand the vehicle upright. – Remove screw cap with membrane and the O-ring. W00089-10 – Manually press the brake caliper toward the brake disc to push back the brake piston. Ensure that brake fluid does not flow out of the brake fluid reservoir;...

  • Page 95: Wheels, Tires 13

    WHEELS, TIRES 13 13.1 Removing the front wheel Preparatory work – Raise the motorcycle with a lift stand. ( p. 48) Main work – Manually press the brake caliper toward the brake disc to push back the brake pistons. Info Make sure that you do not press the brake caliper against the spokes when pushing back the brake pistons.

  • Page 96: Installing The Front Wheel

    13 WHEELS, TIRES 13.2 Installing the front wheel Warning Danger of accidents Oil or grease on the brake discs reduces the braking effect. – Always keep the brake discs free of oil and grease. – Clean the brake discs with brake cleaner when necessary. –...

  • Page 97: Installing The Rear Wheel

    WHEELS, TIRES 13 Main work – Manually press the brake caliper toward the brake disc to push back the brake piston. Info Make sure that you do not press the brake caliper against the spokes when pushing back the brake piston. –...
  • Page 98 13 WHEELS, TIRES Main work – Check the wheel bearing for damage and wear. » If the wheel bearing is damaged or worn: – Change the rear wheel bearing. – Clean and grease shaft seal rings and contact surfaces of the spacers. Long-life grease ( p.

  • Page 99: Checking The Tire Condition

    DOT number. The first two digits indicate the week of manufacture and the last two digits the year of manu- facture. KTM recommends that the tires be changed after 5 years at the latest, regardless of the actual state of H01144-01 wear.

  • Page 100: Checking Spoke Tension

    Other spokes will become looser as a result. – Check spoke tension regularly, and in particular on a new vehicle. (Your authorized KTM workshop will be glad to help.) –...

  • Page 101: Cooling System 14

    COOLING SYSTEM 14 14.1 Cooling system Water pump in the engine ensures forced circulation of the coolant. The pressure resulting from the warming of the cooling system is regulated by a valve in radiator cap . This ensures that operat- ing the vehicle at the specified coolant temperature will not result in a risk of malfunctions.

  • Page 102: Checking The Coolant Level

    14 COOLING SYSTEM 14.3 Checking the coolant level Warning Danger of scalding During motorcycle operation, the coolant gets very hot and is under pressure. – Do not open the radiator, the radiator hoses or other cooling system components if the engine or the cooling system are at operating temperature.

  • Page 103: Refilling With Coolant

    COOLING SYSTEM 14 Warning Danger of poisoning Coolant is harmful to health. – Keep coolant out of the reach of children. – Do not allow coolant to come into contact with the skin, the eyes and clothing. – Consult a doctor immediately if coolant is swallowed. –...
  • Page 104 14 COOLING SYSTEM – Pour coolant in up to level above the radiator fins. Guideline 10 mm (0.39 in) Coolant ( p. 138) 400243-10 – Remove screw and wait until coolant emerges without bub- bles. – Mount and tighten screw Guideline Bleeder screw, cylin- 8 Nm (5.9 lbf ft)

  • Page 105: Changing The Coolant

    COOLING SYSTEM 14 14.6 Changing the coolant Warning Danger of scalding During motorcycle operation, the coolant gets very hot and is under pressure. – Do not open the radiator, the radiator hoses or other cooling system components if the engine or the cooling system are at operating temperature.
  • Page 106 14 COOLING SYSTEM – Remove screw and wait until coolant emerges without bub- bles. – Mount and tighten screw Guideline Bleeder screw, cylin- 8 Nm (5.9 lbf ft) der head W00102-11 – Pour coolant in up to level above the radiator fins. Guideline 10 mm (0.39 in) Coolant (...

  • Page 107: Electrical System 15

    ELECTRICAL SYSTEM 15 15.1 Removing the 12-V battery Caution Danger of burns The voltage regulator gets very hot when the vehicle is driven. – Allow the voltage regulator to cool down before performing any work. Note Environmental hazard 12 V batteries contain environmentally hazardous materials. –...

  • Page 108: Installing The 12-V Battery

    15 ELECTRICAL SYSTEM 15.2 Installing the 12-V battery Main work – Pull up battery holding bracket , insert the 12-V battery into the battery compartment with the terminals facing upwards and secure with battery holding bracket 12-V battery (HJTZ5S-FP-C) ( p.

  • Page 109: Charging The 12-V Battery

    ELECTRICAL SYSTEM 15 15.3 Charging the 12-V battery Warning Risk of injury 12 V batteries contain harmful substances. – Keep 12 V batteries out of the reach of children. – Keep sparks and open flames away from 12 V batteries. – Only charge 12 V batteries in well-ventilated rooms.

  • Page 110: Changing The Main Fuse

    It is also impossible to overcharge the 12-V battery with this battery charger. The charging time may be longer at low temperatures. This battery charger is only suitable for lithium iron phosphate batteries. Read the accompanying KTM Power Parts instruc- tions. Info Never remove cover –...

  • Page 111: Changing The Fuse Of The Fuel Pump

    ELECTRICAL SYSTEM 15 Main work – Pull starter relay from the holder. S05554-10 – Take off protection caps – Remove faulty main fuse Info A faulty fuse has a burned-out fuse wire A spare fuse is located in the starter relay. –...

  • Page 112: Diagnostics Connector

    15 ELECTRICAL SYSTEM Main work – Take off protection cap – Remove the faulty fuse Info A faulty fuse has a burned-out fuse wire – Insert the new fuse for the fuel pump. Fuse (58011109105) ( p. 132) – Check that the electrical system is functioning properly. –...

  • Page 113: Exhaust Control 16

    EXHAUST CONTROL 16 16.1 Programming the end positions of the exhaust control Info If work has been carried out on the exhaust control, the end positions must be reprogrammed. Condition The engine is off. Preparatory work – Remove the seat. ( p.
  • Page 114 16 EXHAUST CONTROL – Mount diagnostics connector on the holder. S05550-10 Finishing work – Mount the seat. ( p. 60)

  • Page 115: Tuning The Engine 17

    TUNING THE ENGINE 17 17.1 Changing the mapping Info The desired engine characteristic can be altered using the combination switch. Changing the mapping also affects the response of the exhaust control. The setting most recently selected is activated again when restarting. The mapping can also be changed during the ride.

  • Page 116: Adjusting The Play In The Throttle Cable

    17 TUNING THE ENGINE Danger Danger of poisoning Exhaust gases are toxic and inhal- ing them may result in unconsciousness and death. – Always make sure there is sufficient ventilation when running the engine. – Use effective exhaust extraction when starting or running the engine in an enclosed space.

  • Page 117: Adjusting The Idle Speed

    Danger of accidents The engine may go out spontaneously if the idle speed is set too low. – Set the idle speed to the specified value. (Your authorized KTM workshop will be glad to help.) – Run the engine until warm.

  • Page 118: Adjusting The Basic Position Of The Shift Lever

    17 TUNING THE ENGINE 17.6 Adjusting the basic position of the shift lever – Remove screw with the washers and take off shift lever 401950-12 – Clean gear teeth of the shift lever and shift shaft. – Mount the shift lever on the shift shaft in the required position and engage gearing.

  • Page 119: Service Work On The Engine 18

    SERVICE WORK ON THE ENGINE 18 18.1 Changing the fuel screen Danger Fire hazard Fuel is highly flammable. The fuel in the fuel tank expands when warm and can escape if overfilled. – Do not fuel the vehicle in the vicinity of open flames or lit cigarettes. –...

  • Page 120: Checking The Gear Oil Level

    18 SERVICE WORK ON THE ENGINE Danger Danger of poisoning Exhaust gases are toxic and inhal- ing them may result in unconsciousness and death. – Always make sure there is sufficient ventilation when running the engine. – Use effective exhaust extraction when starting or running the engine in an enclosed space.

  • Page 121: Adding The Gear Oil

    SERVICE WORK ON THE ENGINE 18 (125 XC US) – Remove the engine guard. ( p. 61) Main work – Remove gear oil drain plug with magnet. – Remove filler plug with the O-ring. – Let the gear oil drain fully. –...
  • Page 122 18 SERVICE WORK ON THE ENGINE Main work – Remove gear oil level monitoring screw S05549-10 – Remove filler plug with the O-ring. – Add gear oil until it emerges from the drill hole of the gear oil level monitoring screw. Engine oil (15W/50) ( p.

  • Page 123: Cleaning, Care 19

    CLEANING, CARE 19 19.1 Cleaning the motorcycle Note Material damage Components become damaged or destroyed if a pressure cleaner is used incorrectly. The high pressure forces water into the electrical components, connectors, throttle cables, and bearings, etc. Pressure which is too high causes malfunctions and destroys components. –...
  • Page 124 19 CLEANING, CARE – Treat bare metal (except for brake discs and the exhaust sys- tem) with a corrosion inhibitor. Preserving materials for paints, metal and rubber p. 140) – Treat all plastic parts and powder-coated parts with a mild cleaning and care product.

  • Page 125: Storage 20

    – Store the vehicle in a dry location that is not subject to large fluctuations in temperature. Info KTM recommends jacking up the motorcycle. – Raise the motorcycle with a lift stand. ( p. 48) – Cover the vehicle with a tarp or a similar cover that is perme- able to air.

  • Page 126: Preparing For Use After Storage

    20 STORAGE 20.2 Preparing for use after storage – Remove the motorcycle from the lift stand. ( p. 48) – Perform checks and maintenance measures when preparing for use. ( p. 28) – Take a test ride. 401059-01...

  • Page 127: Troubleshooting 21

    – Malfunction in the electronic Read out the fault memory using the fuel injection KTM diagnostics tool. – Engine does not speed up Malfunction in the electronic Read out the fault memory using the fuel injection KTM diagnostics tool.
  • Page 128 – Read out the fault memory using the KTM diagnostics tool. – White smoke emission (steam Damaged cylinder head or Check the cylinder head and cylinder in exhaust gas) cylinder head gasket head gasket.

  • Page 129: Blink Code 22

    BLINK CODE 22 Blink code for malfunction indicator lamp 14 Malfunction indicator lamp flashes 1x long, 4x short Crankcase pressure sensor – difference too high between sensor and engine control Error level condition unit Blink code for malfunction indicator lamp 09 Malfunction indicator lamp flashes 9x short Error level condition Crankcase pressure sensor - short circuit to ground...
  • Page 130 22 BLINK CODE Blink code for malfunction indicator lamp 37 Malfunction indicator lamp flashes 3x long, 7x short Ignition coil – circuit fault Error level condition Blink code for malfunction indicator lamp 02 Malfunction indicator lamp flashes 2x short Crankshaft speed sensor – synchronization faulty Error level condition Crankshaft speed sensor –...

  • Page 131: Technical Data 23

    TECHNICAL DATA 23 23.1 Engine Design 1-cylinder 2-stroke engine, water-cooled, with reed intake and exhaust control Displacement 124.8 cm³ (7.616 cu in) Stroke 54.5 mm (2.146 in) Bore 54 mm (2.13 in) Idle speed 1,400 … 1,500 rpm Crankshaft bearing 1 grooved ball bearing/1 roller bearing Conrod bearing Needle bearing...
  • Page 132 23 TECHNICAL DATA Screw, locking lever 6 Nm (4.4 lbf ft) Loctite ® 243™ Screw, retaining bracket, rotary 6 Nm (4.4 lbf ft) valve Loctite ® 2701™ Screw, stator 6 Nm (4.4 lbf ft) Loctite ® 243™ Screw, stator 6 Nm (4.4 lbf ft) Loctite ®...

  • Page 133: Capacities

    TECHNICAL DATA 23 Nut, inner clutch hub M18x1.5 120 Nm (88.5 lbf ft) Nut, primary gear wheel M18LHx1.5 120 Nm (88.5 lbf ft) Loctite ® 243™ 23.3 Capacities 23.3.1 Gear oil Gear oil 0.80 l (0.85 qt.) Engine oil (15W/50) ( p.

  • Page 134: Electrical System

    The tires specified represent one of the possible series production tires. For alternative manufacturers, if any, contact an authorized dealer or qualified tire dealership. If local road approval regulations apply, these and the respective technical specifications must be observed. Additional information is available in the Service section under: KTM.COM 23.7 Fork 23.7.1...

  • Page 135: Xc Us

    TECHNICAL DATA 23 Oil capacity external mechanism ml (7.78 fl. oz.) Fork oil (SAE 4) (48601166S1) + 10 + 0.34 − 50 − 1.69 left p. 139) Oil capacity external mechanism ml (7.78 fl. oz.) Fork oil (SAE 4) (48601166S1) + 10 + 0.34 −...

  • Page 136: Xc Us

    23 TECHNICAL DATA Sport 13 clicks Spring preload 7 mm (0.28 in) Spring rate Weight of rider: 65 … 75 kg (143 … 165 lb.) 36 N/mm (206 lb/in) Weight of rider: 75 … 85 kg (165 … 187 lb.) 39 N/mm (223 lb/in) Weight of rider: 85 …...

  • Page 137: Chassis Tightening Torques

    TECHNICAL DATA 23 23.9 Chassis tightening torques Hose clamp, radiator 2.4 Nm (1.77 lbf ft) Hose clip, inlet sleeve to throttle 2.8 Nm (2.07 lbf ft) valve body Screw, air filter box, on subframe EJOT PT ® K60x20AL 5 Nm (3.7 lbf ft) Screw, combination switch EJOT PT ®...
  • Page 138 23 TECHNICAL DATA Screw, chain guide on link fork at M6x45 10 Nm (7.4 lbf ft) the front Screw, chain guide on link fork at 10 Nm (7.4 lbf ft) the rear Screw, chain guide on link fork at M6x16 10 Nm (7.4 lbf ft) the rear Screw, chain sliding guard...
  • Page 139 TECHNICAL DATA 23 Screw, subframe, bottom 30 Nm (22.1 lbf ft) Loctite ® 2701™ Screw, subframe, bottom 35 Nm (25.8 lbf ft) Loctite ® 2701™ Screw, top steering stem 20 Nm (14.8 lbf ft) Loctite ® 243™ Screw, top triple clamp 17 Nm (12.5 lbf ft) Engine bracket screw 60 Nm (44.3 lbf ft)

  • Page 140: 24 Substances

    24 SUBSTANCES Brake fluid DOT 4 / DOT 5.1 Standard/classification – Guideline – Use only brake fluid that complies with the specified standard (see specifications on the container) and that exhibits the corresponding properties. Recommended supplier Castrol – REACT PERFORMANCE DOT 4 MOTOREX ®...
  • Page 141 SUBSTANCES 24 Recommended supplier MOTOREX ® – Cross Power 2T Fork oil (SAE 4) (48601166S1) Standard/classification – SAE ( p. 142) (SAE 4) Guideline – Use only oils that comply with the specified standards (see specifications on the container) and that exhibit the corresponding properties.

  • Page 142: 25 Auxiliary Substances

    25 AUXILIARY SUBSTANCES Air filter cleaner Recommended supplier MOTOREX ® – Racing Bio Dirt Remover Chain cleaner Recommended supplier MOTOREX ® – Chain Clean Fuel additive Recommended supplier MOTOREX ® – Fuel Stabilizer High viscosity grease Recommended supplier ® – LGHB 2 Long-life grease Recommended supplier...
  • Page 143 AUXILIARY SUBSTANCES 25 Silicone spray Recommended supplier MOTOREX ® – Silicone Spray Special cleaner for glossy and matte paint finishes, metal and plastic surfaces Recommended supplier MOTOREX ® – Quick Cleaner Special grease (00062010053) Recommended supplier Klüber Lubrication ® – Klüberfood NH1 34‑401 Universal oil spray Recommended supplier...

  • Page 144: 26 Standards

    26 STANDARDS JASO T903 MA2 Different technical development directions required a separate specification for motorcycles – the JASO T903 MA2 standard. Earlier, engine oils from the automobile industry were used for motorcycles because there was no separate motor- cycle specification. Whereas long service intervals are demanded for automobile engines, the focus for motorcycle engines is on high performance at high engine speeds.

  • Page 145: Index Of Special Terms 27

    INDEX OF SPECIAL TERMS 27 On-board diagnosis Vehicle system, which monitors the specified parame- ters of the vehicle electronics...

  • Page 146: 28 List Of Abbreviations

    28 LIST OF ABBREVIATIONS Art. no. Article number circa compare e.g. for example etc. et cetera i.a. inter alia number poss. possibly...

  • Page 147: List Of Symbols 29

    LIST OF SYMBOLS 29 29.1 Yellow and orange symbols Yellow and orange symbols indicate an error condition that requires prompt intervention. Active driving aids are also represented by yellow or orange symbols. Malfunction indicator lamp lights up/flashes orange – The OBD has detected a malfunction in the vehicle electronics.

  • Page 148: Index

    INDEX cleaning ......71 INDEX Chain guide 12-V battery checking ......74 charging .
  • Page 149 INDEX Figures ....... 9 Hand brake lever ..... . . 14 Filling up basic position, adjusting .
  • Page 150 INDEX Plug-in stand ......20 Steering head bearing lubricating ......55 Preparing for use Steering head bearing play advice on preparing for first use .
  • Page 151 *3214638en* 3214638en 14.11.2022 KTM Sportmotorcycle GmbH 5230 Mattighofen/Austria Photo: Mitterbauer/KISKA/KTM KTM.COM...

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