KTM 125 SX 2019 Owner's Manual
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KTM 125 SX 2019 Owner's Manual

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OWNER'S MANUAL
2019
125 SX
150 SX
Art. no. 3213847en

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Summary of Contents for KTM 125 SX 2019

  • Page 1 OWNER'S MANUAL 2019 125 SX 150 SX Art. no. 3213847en...
  • Page 3 DEAR KTM CUSTOMER Congratulations on your decision to purchase a KTM motorcycle. You are now the owner of a state-of-the-art DEAR KTM CUSTOMER sports motorcycle that will give you enormous pleasure if you service and maintain it properly. We hope you enjoy riding this motorcycle! Enter the serial numbers of your vehicle below.

  • Page 4: Table Of Contents

    TABLE OF CONTENTS Preparing the vehicle for difficult TABLE OF CONTENTS MEANS OF REPRESENTATION ...... 5 operating conditions......21 Symbols used ........5 Preparing vehicle for rides on dry Formats used........5 sand ..........22 Preparing vehicle for rides on wet SAFETY ADVICE..........
  • Page 5 TABLE OF CONTENTS 10.14 Adjusting the compression damping 11.38 Checking the frame ...... 72 of the fork ........42 11.39 Checking the swingarm ....72 10.15 Adjusting the rebound damping of 11.40 Checking the throttle cable routing ..72 the fork........... 43 11.41 Checking the rubber grip ....
  • Page 6 TABLE OF CONTENTS 15.2 Adjusting the play in the throttle 20.7.2 125/150 SX US......125 cable ......... 100 20.8 Shock absorber ......125 15.3 Carburetor setting ......101 20.8.1 125/150 SX EU......125 Carburetor – idle ......103 15.4 20.8.2 125/150 SX US......

  • Page 7: Means Of Representation 1

    All work marked with this symbol requires specialist knowledge and technical understanding. In the interest of your own safety, have these jobs performed by an authorized KTM workshop! Your motorcycle will be optimally cared for there by specially trained experts using the auxiliary tools required.

  • Page 8: Safety Advice

    2 SAFETY ADVICE Use definition – intended use This vehicle is designed and built to withstand the normal stresses and strains of competitive use. 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

    Only operate the vehicle when it is in perfect technical condition, in accordance with its intended use, and in a safe and environmentally compatible manner. The vehicle should only be used by trained persons. Have malfunctions that impair safety promptly eliminated by an authorized KTM workshop. Adhere to the information and warning labels on the vehicle.

  • Page 10: Protective Clothing

    – 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. Work rules Special tools are necessary for certain tasks.

  • Page 11: Important Notes 3

    Manufacturer and implied warranty The work specified in the service schedule may only be performed in an authorized KTM workshop and must be recorded in both the Service & Warranty Booklet and in KTM Dealer.net, otherwise any warranty coverage will become void.
  • Page 12 3 IMPORTANT NOTES A list of authorized KTM dealers can be found on the KTM website. International KTM Website: http://www.ktm.com...

  • Page 13: View Of Vehicle 4

    VIEW OF VEHICLE 4 View of vehicle, front left (example) K01145-10 Hand brake lever ( p. 15) Kill switch ( p. 15) Clutch lever ( p. 15) Air filter box cover Plug-in stand Shift lever ( p. 17) Choke ( p.

  • Page 14: View Of Vehicle, Rear Right (Example)

    4 VIEW OF VEHICLE View of vehicle, rear right (example) K01146-10 Seat Filler cap Throttle grip ( p. 15) Kick starter ( p. 18) Foot brake lever ( p. 18) Shock absorber compression adjustment Level viewer for brake fluid, rear Shock absorber rebound adjustment...

  • Page 15: Serial Numbers 5

    SERIAL NUMBERS 5 Chassis number The chassis number is stamped on the right side of the steer- ing head. 401945-10 Type label The type label is fixed to the front of the steering head. 401946-10 Engine number The engine number is stamped on the left side of the engine under the engine sprocket.

  • Page 16: Shock Absorber Article Number

    5 SERIAL NUMBERS 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. 0 0 1 401948-10...

  • Page 17: Controls 6

    CONTROLS 6 Clutch lever Clutch lever is fitted on the handlebar on the left. The clutch is activated hydraulically and adjusts itself automati- cally. F00009-10 Hand brake lever Hand brake lever is fitted on the right side of the handlebar. The front brake is engaged using the hand brake lever.

  • Page 18: Opening The Filler Cap

    6 CONTROLS Opening the filler cap Danger Fire hazard Fuel is highly flammable. The fuel in the fuel tank expands when warm and can escape if overfilled. – Do not refuel the vehicle in the vicinity of open flames or lit cigarettes. –...

  • Page 19: Fuel Tap

    CONTROLS 6 Fuel tap The fuel tap is on the left side of the fuel tank. Open or close the fuel supply to the carburetor using tap han- on the fuel tap. Possible states Fuel supply closed OFF – Fuel cannot flow from the fuel tank •...

  • Page 20: Kick Starter

    6 CONTROLS The gear positions can be seen in the photograph. The neutral or idle position is between the first and second gears. 401950-11 6.10 Kick starter Kick starter is fitted on the right side of the engine. The top part of the kick starter pivots. Info 0 0 1 Before riding, swing the top part of the kick starter inward...

  • Page 21: Service Hour Counter

    CONTROLS 6 6.13 Service hour counter The service hour counter is fitted in front of the handlebar. It shows the total number of service hours of the engine. The service hour counter begins counting when the engine is started and stops when the engine is switched off. Info It is not possible to delete or adjust anything on the service hour counter.

  • Page 22: Preparing For Use

    When using your motorcycle, remember that others may feel disturbed by excessive noise. – Make sure that the pre-delivery inspection work has been carried out by an authorized KTM workshop. You receive a delivery certificate and the Service and Warranty Booklet at vehicle handover.

  • Page 23: Running In The Engine

    PREPARING FOR USE 7 – Adjust the basic position of the foot brake lever. p. 83) – Set the basic position of the shift lever. p. 105) – Get used to handling the motorcycle on a suitable surface before undertaking a more challenging trip. Info Your motorcycle is not approved for use on public roads.

  • Page 24: Preparing Vehicle For Rides On Dry Sand

    In the event of scalding, rinse the area affected immediately with lukewarm water. – Change the radiator cap. – Mount a dust cover on the air filter. Dust cover for air filter (79006920000) Info Observe fitting instructions for KTM PowerParts. M01104-01...

  • Page 25: Preparing Vehicle For Rides On Wet Sand

    Sand cover for air filter (79006922000) Info Observe fitting instructions for KTM PowerParts. M01105-01 – Adjust the carburetor jetting and setting. Info Your authorized KTM workshop can recommend the right carburetor tuning. M01107-01 – Clean the chain. Chain cleaner ( p. 131) –...
  • Page 26 Waterproofing device for air filter (79006921000) Info Observe fitting instructions for KTM PowerParts. M01106-01 – Adjust the carburetor jetting and setting. Info Your authorized KTM workshop can recommend the right carburetor tuning. M01107-01 – Clean the chain. Chain cleaner ( p. 131) –...

  • Page 27: Preparing Vehicle For Rides On Wet And Muddy Circuits

    Waterproofing device for air filter (79006921000) Info Observe fitting instructions for KTM PowerParts. M01106-01 – Adjust the carburetor jetting and setting. Info Your authorized KTM workshop can recommend the right carburetor tuning. M01107-01 – Mount the steel sprocket. – Clean the motorcycle. ( p.

  • Page 28: Preparing Vehicle For Low Temperatures Or Snow

    Fit a rain cover on the air filter. Waterproofing device for air filter (79006921000) Info Observe fitting instructions for KTM PowerParts. M01106-01 – Adjust the carburetor jetting and setting. Info Your authorized KTM workshop can recommend the right carburetor tuning. M01107-01...

  • Page 29: Riding Instructions 8

    RIDING INSTRUCTIONS 8 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 30: Starting Off

    Do not change into a low gear at high engine speed. Info If you hear unusual noises while riding, stop immediately, switch off the engine, and contact an autho- rized KTM workshop. First gear is used for starting off and for steep inclines. –...

  • Page 31: Applying The Brakes

    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 32: Transporting

    8 RIDING INSTRUCTIONS 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 33: Refueling

    RIDING INSTRUCTIONS 8 Refueling Danger Fire hazard Fuel is highly flammable. The fuel in the fuel tank expands when warm and can escape if overfilled. – Do not refuel the vehicle in the vicinity of open flames or lit cigarettes. – Switch off the engine for refueling.

  • Page 34: Service Schedule

    Different service intervals may apply in your country, depending on the local operating conditions. 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 35: Recommended Work

    Final check: Check the vehicle for operating safety and take a test ride. ○ ● ● ● ● Make the service entry in the KTM Dealer.net and in the Service and Warranty Booklet. ○ One-time interval ● Periodic interval Recommended work...

  • Page 36: 10 Tuning The Chassis

    – As delivered, KTM offroad motorcycles are adjusted for an average rider's weight (with full protective clothing). Guideline Standard rider weight 75 …...

  • Page 37: 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 low-speed setting can be seen in slow to normal compression of the shock absorber.

  • Page 38: 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 setting can be seen in fast compression of the shock absorber.

  • Page 39: Measuring The Rear Wheel Dimension Unloaded

    TUNING THE CHASSIS 10 – Turn adjusting screw clockwise up to the last perceptible click. – Turn counterclockwise by the number of clicks corresponding to the shock absorber type. Guideline Rebound damping (125/150 SX EU) Comfort 17 clicks Standard 15 clicks K01131-10 Sport 13 clicks...

  • Page 40: Checking The Static Sag Of The Shock Absorber

    10 TUNING THE CHASSIS 10.8 Checking the static sag of the shock absorber – Measure dimension of rear wheel unloaded. ( p. 37) – Hold the motorcycle upright with the aid of an assistant. – Again measure the distance between the rear axle and mark- ing SAG on the rear fender using the sag gauge.

  • Page 41: 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 42: Adjusting The Riding Sag

    10 TUNING THE CHASSIS 10.11 Adjusting the riding sag Preparatory work – Raise the motorcycle with a lift stand. ( p. 46) – Remove the shock absorber. p. 55) – After removing the shock absorber, clean it thoroughly. Main work –...

  • Page 43: 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 pump or the fork. Read the accompanying KTM PowerParts instructions. – Adjust the air pressure as specified. Guideline Air pressure 8.3 bar (120 psi)

  • Page 44: Adjusting The Compression Damping Of The Fork

    10 TUNING THE CHASSIS Info Never adjust the air pressure to a value outside the stated range. – Disconnect the fork pump from the left fork leg. When disconnecting, excess pressure will escape from the hose – the fork leg itself does not lose any air. The fork pump indicator switches off automatically after 80 seconds.

  • Page 45: Adjusting The Rebound Damping Of The Fork

    TUNING THE CHASSIS 10 10.15 Adjusting the rebound damping of the fork Info The hydraulic rebound damping determines the fork suspension behavior. – Remove protection cap – Turn adjusting screw clockwise all the way. Info Adjusting screw is located at the lower end of the right fork leg.

  • Page 46: 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. Preparatory work –...
  • Page 47 TUNING THE CHASSIS 10 Finishing work – Mount the handlebar cushion.

  • Page 48: 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 49: Cleaning The Dust Boots Of The Fork Legs

    SERVICE WORK ON THE CHASSIS 11 Main work – Release bleeder screws Any excess pressure escapes from the interior of the fork. – Tighten the bleeder screws. H01182-12 Finishing work – Remove the motorcycle from the lift stand. ( p. 46) 11.4 Cleaning the dust boots of the fork legs Preparatory work...

  • Page 50: Removing The Fork Legs

    11 SERVICE WORK ON THE CHASSIS 11.5 Removing the fork legs Preparatory work – Raise the motorcycle with a lift stand. ( p. 46) – Remove the front wheel. p. 89) Main work – Remove screws and take off the clamp. –...

  • Page 51: Removing The Fork Protector

    SERVICE WORK ON THE CHASSIS 11 – Position the brake caliper. Mount and tighten screws Guideline Screw, front 25 Nm (18.4 lbf ft) Loctite ® 243™ brake caliper – Position the brake line and clamp. Mount and tighten screws K01143-11 Finishing work –...

  • Page 52: Installing The Lower Triple Clamp

    11 SERVICE WORK ON THE CHASSIS Main work – Remove screw – Remove screw – Pull off the upper triple clamp with the handlebar and hang to the side. Info Protect the components against damage by covering them. K01149-10 Do not kink the cables and lines. –...
  • Page 53 SERVICE WORK ON THE CHASSIS 11 – Position the fork legs. Air release screw of the right fork leg is positioned to the front. Valve of the left fork leg faces the front. Info The air suspension AER valve is located in the left fork leg.

  • Page 54: Checking The Play Of The Steering Head Bearing

    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 55: Adjusting The Steering Head Bearing Play

    SERVICE WORK ON THE CHASSIS 11 Finishing work – Remove the motorcycle from the lift stand. ( p. 46) 11.12 Adjusting the steering head bearing play Preparatory work – Raise the motorcycle with a lift stand. ( p. 46) – Remove the handlebar cushion.

  • Page 56: Removing The Start Number Plate

    11 SERVICE WORK ON THE CHASSIS 11.14 Removing the start number plate – Remove screw – Disconnect the brake line at the start number plate. Take off the start number plate. F00012-10 11.15 Installing the start number plate – Connect the brake line at the start number plate. –...

  • Page 57: Removing The Shock Absorber

    SERVICE WORK ON THE CHASSIS 11 11.18 Removing the shock absorber Preparatory work – Raise the motorcycle with a lift stand. ( p. 46) Main work – Remove the cable ties. – Remove screws with the washers. – Remove screw –...

  • Page 58: Installing The Shock Absorber

    11 SERVICE WORK ON THE CHASSIS – Remove nut and pull out the swingarm pivot. – Push the swingarm back and secure it against falling over. K01138-10 – Hold the shock absorber and remove screw K01139-10 – Remove the shock absorber carefully at the bottom. K01140-10 11.19 Installing the shock absorber...
  • Page 59 SERVICE WORK ON THE CHASSIS 11 – Position the swingarm and mount the swingarm pivot. Info Pay attention to flat area – Mount and tighten nut Guideline Nut, swingarm pivot M16x1.5 100 Nm (73.8 lbf ft) K01147-10 – Mount the chain. –...

  • Page 60: Removing The Seat

    11 SERVICE WORK ON THE CHASSIS – Position left frame protector. – Insert right frame protector from below and push to the rear. – Mount and tighten screws with the washers. Guideline Screw, frame protec- 3 Nm (2.2 lbf ft) –...

  • Page 61: Removing The Air Filter Box Cover

    SERVICE WORK ON THE CHASSIS 11 – Mount and tighten screw Guideline Remaining screws, 10 Nm (7.4 lbf ft) chassis K01133-10 11.22 Removing the air filter box cover Condition The air filter box cover is secured. – Remove the seat. ( p.

  • Page 62: Installing The Air Filter Box Cover

    11 SERVICE WORK ON THE CHASSIS 11.23 Installing the air filter box cover Condition The air filter box cover is secured. – Insert the air filter box cover in area and clip it into area K01154-11 – Mount and tighten screw Guideline Screw, air filter box EJOT PT...

  • Page 63: Cleaning The Air Filter And Air Filter Box

    SERVICE WORK ON THE CHASSIS 11 Main work – Detach retaining tab . Remove air filter with air filter sup- port. – Take off air filter from air filter support. K01156-10 11.25 Cleaning the air filter and air filter box Note Environmental hazard Hazardous substances cause environmental damage.

  • Page 64: Installing The Air Filter

    11 SERVICE WORK ON THE CHASSIS 11.26 Installing the air filter Main work – Mount the clean air filter on the air filter support. – Grease the air filter in area Long-life grease ( p. 131) 102178-10 – Insert the air filter and position the top retaining pin bushing The air filter is correctly positioned.

  • Page 65: Installing The Main Silencer

    SERVICE WORK ON THE CHASSIS 11 – Remove screws with the washers. – Pull off the main silencer from the manifold at rubber sleeve K01187-10 11.29 Installing the main silencer – Position the main silencer with rubber sleeve – Mount and tighten screws with the washers.

  • Page 66: Removing The Fuel Tank

    11 SERVICE WORK ON THE CHASSIS Main work – Remove screws . Pull out inner tube – Remove the glass fiber yarn filling from the inner tube. – Clean the parts that need to be reinstalled and check for dam- age.

  • Page 67: Installing The Fuel Tank

    SERVICE WORK ON THE CHASSIS 11 Main work – Pull off the fuel hose. Info Remaining fuel may flow out of the fuel hose. – Remove screws K01189-10 – Remove screw with the rubber bushing. – Pull the fuel tank breather hose off the tank lid. K01190-10 –...

  • Page 68: Checking The Chain For Dirt

    11 SERVICE WORK ON THE CHASSIS Main work – Check the throttle cable routing. ( p. 72) – Position the fuel tank and fit the two spoilers to the sides of the radiator bracket. – Make sure that no cables or throttle cables are trapped or dam- aged.

  • Page 69: Cleaning The Chain

    SERVICE WORK ON THE CHASSIS 11 11.34 Cleaning the chain Warning Danger of accidents Oil or grease on the tires reduces the road grip. – Remove the lubricant from the tires using a suitable cleaning agent. Warning Danger of accidents Oil or grease on the brake discs reduces the braking effect. –...

  • Page 70: Adjusting The Chain Tension

    11 SERVICE WORK ON THE CHASSIS Main work – Pull the chain at the end of the chain sliding piece upward to measure chain tension Guideline The lower chain section must be taut. Info Chain wear is not always even, so you should repeat this measurement at different chain positions.

  • Page 71: Checking The Chain, Rear Sprocket, Engine Sprocket, And Chain Guide

    SERVICE WORK ON THE CHASSIS 11 Main work – Loosen nut – Loosen nuts – Adjust the chain tension by turning adjusting screws to the left and right. Guideline Chain tension 55 … 58 mm (2.17 … 2.28 in) Turn adjusting screws on the left and right so that the markings on the left and right chain adjusters are in the same position relative to reference marks...
  • Page 72 11 SERVICE WORK ON THE CHASSIS – Pull at the top part of the chain with the specified weight Guideline Weight, chain wear measure- 10 … 15 kg (22 … 33 lb.) ment – Measure distance of 18 chain rollers in the lower chain section.
  • Page 73 SERVICE WORK ON THE CHASSIS 11 – Check the chain sliding piece for wear. » If the lower edge of the chain pins is in line with or below the chain sliding piece: – Change the chain sliding piece. – Check that the chain sliding piece is firmly seated.

  • Page 74: Checking The Frame

    – Change the swingarm. Info Always change a damaged swingarm. Repair of the swingarm is not authorized by KTM. S02305-01 11.40 Checking the throttle cable routing Warning Danger of accidents The throttle cable may slip out of the guide if routed incorrectly.

  • Page 75: Checking The Rubber Grip

    SERVICE WORK ON THE CHASSIS 11 Main work – Check the throttle cable routing. The throttle cable must be routed along the back of the handlebar, to the right of the frame, above the fuel tank bracket, and to the carburetor. The throttle cable must be fixed on the fuel tank bracket with a rubber band.

  • Page 76: Adjusting Basic Position Of Clutch Lever

    11 SERVICE WORK ON THE CHASSIS 11.42 Adjusting basic position of clutch lever – Adjust the basic setting 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 77: Changing The Hydraulic Clutch Fluid

    SERVICE WORK ON THE CHASSIS 11 Info Clean up overflowed or spilled brake fluid immediately with water. 11.44 Changing the hydraulic clutch fluid Warning Skin irritation Brake fluid causes skin irritation. – Keep brake fluid out of the reach of children. –...
  • Page 78 11 SERVICE WORK ON THE CHASSIS – Now inject the liquid into the system until it emerges from the drill hole of the master cylinder without bubbles. – Now and then, extract fluid from the master cylinder reservoir to prevent overflow. –...

  • Page 79: 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 80: 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 81: 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 82: Checking The Front Brake Linings

    Checking the front brake linings 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 minimum thickness ≥...
  • Page 83 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 84 12 BRAKE SYSTEM Info Make sure that you do not press the brake caliper against the spokes when pushing back the brake pistons. – Remove cotter pin , pull out pin , and remove the brake linings. – Clean the brake caliper and brake caliper support. 101737-10 –...

  • Page 85: Checking The Free Travel Of Foot Brake Lever

    BRAKE SYSTEM 12 12.8 Checking the free travel of foot brake lever Warning Danger of accidents The brake system fails in the event of overheating. If there is no free travel on the foot brake lever, pressure builds up in the brake system on the rear brake.

  • Page 86: 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 87 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 88: Checking The Brake Linings Of The Rear Brake

    Checking the brake linings of the rear brake 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 minimum thickness ≥...
  • Page 89 BRAKE SYSTEM 12 Info Never use DOT 5 brake fluid. It is silicone-based and purple in color. Oil seals and brake lines are not designed for DOT 5 brake fluid. Avoid contact between brake fluid and painted parts. Brake fluid attacks paint. Only use clean brake fluid from a sealed container.
  • Page 90 12 BRAKE SYSTEM – Add brake fluid to level Brake fluid DOT 4 / DOT 5.1 ( p. 129) – Mount and tighten screw cap with membrane and the O-ring. Info Clean up overflowed or spilled brake fluid immediately with water. K01185-10...

  • Page 91: Wheels, Tires 13

    WHEELS, TIRES 13 13.1 Removing the front wheel Preparatory work – Raise the motorcycle with a lift stand. ( p. 46) Main work – Press the brake caliper onto the brake disc by hand in order 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...

  • Page 92: 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 93: Installing The Rear Wheel

    WHEELS, TIRES 13 Main work – Press the brake caliper onto the brake disc by hand in order to push back the brake piston. Info Make sure when pushing back the brake piston that you do not press the brake caliper against the spokes. –...
  • Page 94 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 surface of the spacers. Long-life grease ( p.

  • Page 95: 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 96: 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 97: 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 98: Removing The Radiator Cover

    14 COOLING SYSTEM – Position the matching radiator cover ( p. 95). The larger catch is located at the top left. Info Do not use both radiator covers at the same time. H01341-10 – Position radiator shield – Mount and tighten screws Guideline Remaining screws, 10 Nm (7.4 lbf ft)

  • Page 99: Checking The Coolant Level

    COOLING SYSTEM 14 Warning Danger of poisoning Coolant is toxic and a health hazard. – 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 100: Draining The Coolant

    14 COOLING SYSTEM Condition The engine is cold. – Stand the motorcycle upright on a horizontal surface. – Remove the radiator cap. – Check the coolant level in the radiator. 10 mm (0.39 in) Coolant level above the radiator fins »...

  • Page 101: Refilling With Coolant

    COOLING SYSTEM 14 14.8 Refilling with coolant Warning Danger of poisoning Coolant is toxic and a health hazard. – Keep coolant out of the reach of children. – Do not allow coolant to come into contact with the skin, the eyes and clothing. –...

  • Page 102: 15 Tuning The Engine

    15 TUNING THE ENGINE 15.1 Checking the play in the throttle cable – Check the throttle grip for smooth operation. – Move the handlebar to the straight-ahead position. Move the throttle grip back and forth slightly to determine the play in throttle cable Play in throttle cable 2 …...

  • Page 103: Carburetor Setting

    TUNING THE ENGINE 15 – Turn barrel adjuster so that there is play in the throttle cable at the throttle grip. Guideline Play in throttle cable 2 … 3 mm (0.08 … 0.12 in) – Tighten nut – Slide on sleeve 400192-11 Finishing work –...
  • Page 104 15 TUNING THE ENGINE Idling jet IJ The idling jet has the greatest influence in the low to mid throttle slide range. If the engine stutters when idling or accelerating with a partially open throttle slide, a smaller idling jet must be used.

  • Page 105: Carburetor - Idle

    TUNING THE ENGINE 15 402674-01 Column 2 corresponds to a needle in the standard position. Column 1 corresponds to a needle which is half a clip leaner. Column 3 corresponds to a needle which is half a clip richer. Column 4 specifies the diameter of the first cylindrical part of the needle. The smaller the diameter of the first cylindrical part of the needle, the richer the carburation.
  • Page 106 15 TUNING THE ENGINE Carburetor – adjusting the idle speed 15.5 – Screw in idle air adjusting screw all the way and turn it to the specified basic position. Info The basic adjustment is shown under the respective model. – Run the engine until warm.

  • Page 107: Plug-In Connector Of Ignition Timing

    TUNING THE ENGINE 15 15.6 Plug-in connector of ignition timing map adjustment Plug-in connector of the ignition timing map adjustment is located on the frame under the fuel tank. Possible states Soft – The plug-in connector of the ignition timing map •...
  • Page 108 15 TUNING THE ENGINE – Clean gear teeth of the shift lever and shift shaft. – Mount the shift lever on the shift shaft in the required position and engage the gearing. Info The range of adjustment is limited. The shift lever must not come into contact with any other vehicle components during the shift procedure.

  • Page 109: Service Work On The Engine 16

    SERVICE WORK ON THE ENGINE 16 16.1 Emptying the carburetor float chamber Danger Fire hazard Fuel is highly flammable. The fuel in the fuel tank expands when warm and can escape if overfilled. – Do not refuel the vehicle in the vicinity of open flames or lit cigarettes. –...

  • Page 110: Checking The Gear Oil Level

    16 SERVICE WORK ON THE ENGINE 16.2 Checking the gear oil level Info The gear oil level must be checked when the engine is cold. Preparatory work – Stand the motorcycle upright on a horizontal surface. Main work – Remove screw for checking gear oil level –...

  • Page 111: Adding Gear Oil

    SERVICE WORK ON THE ENGINE 16 Main work – Remove the gear oil drain plug with magnet – Remove gear oil drain plug – Let the gear oil drain fully. – Clean the gear oil drain plug thoroughly. – Clean the sealing surface on the engine. –...
  • Page 112 16 SERVICE WORK ON THE ENGINE Main work – Remove screw for checking gear oil level K01182-10 – Remove filler plug with O-ring. – Add gear oil until it emerges from the drill hole of the gear oil monitoring screw. Engine oil (15W/50) ( p.

  • Page 113: Cleaning, Care 17

    CLEANING, CARE 17 17.1 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 114 17 CLEANING, CARE – Treat bare metal parts (except for brake discs and exhaust sys- tem) with anti-corrosion materials. Preserving materials for paints, metal and rubber p. 132) – Treat all plastic parts and powder-coated parts with a mild cleaning and care product. Special cleaner for glossy and matte paint finishes, metal and plastic surfaces ( p.

  • Page 115: Storage 18

    93) – 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. 46) – Cover the vehicle with a tarp or similar cover that is permeable to air.

  • Page 116: Preparing For Use After Storage

    18 STORAGE 18.2 Preparing for use after storage – Remove the motorcycle from the lift stand. ( p. 46) – Perform checks and maintenance measures when preparing for use. ( p. 27) – Take a test ride. 401059-01...

  • Page 117: Troubleshooting 19

    TROUBLESHOOTING 19 Faults Possible cause Action – Engine turns but does not start Operating error Carry out the start procedure. p. 27) – Motorcycle was out of use for a Empty the carburetor float chamber. long time and there is old fuel p.
  • Page 118 19 TROUBLESHOOTING Faults Possible cause Action – Engine stalls or is popping into Engine takes in bad air Check the intake flange and carburetor the carburetor for tightness. – The connector or ignition coil is Clean the connector and treat it with loose or oxidized contact spray.

  • Page 119: Technical Data 20

    TECHNICAL DATA 20 20.1 Engine 20.1.1 All 125 models 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) Crankshaft bearing 1 grooved ball bearing/1 roller bearing Conrod bearing Needle bearing Piston pin bearing...

  • Page 120: Engine Tightening Torques

    20 TECHNICAL DATA Gearbox 6-gear, claw shifted Transmission ratio First gear 14:32 Second gear 15:30 Third gear 17:28 Fourth gear 19:27 Fifth gear 19:23 Sixth gear 22:24 Ignition Contactless controlled fully electronic ignition with digital ignition adjustment, type Kokusan Spark plug NGK BR9 ECMVX Spark plug electrode gap 0.60 mm (0.0236 in)
  • Page 121 TECHNICAL DATA 20 Screw, intermediate clutch cover M6x25 10 Nm (7.4 lbf ft) Screw, intermediate clutch cover M6x30 10 Nm (7.4 lbf ft) Screw, kick starter stop plate 10 Nm (7.4 lbf ft) Screw, outer clutch cover M6x20 8 Nm (5.9 lbf ft) Screw, outer clutch cover M6x50 8 Nm (5.9 lbf ft)

  • Page 122: Carburetor

    20 TECHNICAL DATA 20.3 Carburetor 20.3.1 All 125 models Carburetor type MIKUNI TMX 38 Carburetor identification number TMX 38 87 Needle position 2nd position from top Jet needle 6BFY43‑71 (6BFY42‑71) Main jet 500 (480, 490, 520, 540, 560) Idling jet 35 (30 / 32.5 / 37.5 / 40) Starting jet Needle jet...

  • Page 123: Carburetor - Basic Setting For Sandy Surfaces (All 125 Models)

    TECHNICAL DATA 20 TEMP Temperature Idle air adjusting screw open Idling jet Needle Needle position from top Main jet Info Do not use on sandy terrain. 20.3.3 Carburetor - basic setting for sandy surfaces (All 125 models) Idle air adjusting screw Open 2 turns Idling jet...

  • Page 124: All 150 Models

    20 TECHNICAL DATA 20.3.4 All 150 models Carburetor type MIKUNI TMX 38 Carburetor identification number TMX 38 88 Needle position 3rd position from top Jet needle 6BFY42‑71 (6BFY43‑71) Main jet 470 (460, 480, 490, 500, 520) Idling jet 30 (25 / 27.5 / 32.5 / 35) Starting jet Needle jet S‑4...

  • Page 125: Basic Carburetor Setting For Sandy Surfaces (All 150 Models)

    TECHNICAL DATA 20 Idling jet Needle Needle position from top Main jet Info Do not use on sandy terrain. 20.3.6 Basic carburetor setting for sandy surfaces (All 150 models) Idle air adjusting screw Open 2 turns Idling jet 37.5 Jet needle 6BFY42‑71 Needle position 3rd position from top...

  • Page 126: Tires

    100/90 - 19 57M TT Dunlop GEOMAX MX3S Dunlop GEOMAX MX3S The tires specified represent one of the possible series production tires. Additional information is available in the Service section under: http://www.ktm.com 20.7 Fork 20.7.1 125/150 SX EU Fork article number 34.18.8S.01...

  • Page 127: 125/150 Sx Us

    TECHNICAL DATA 20 Oil capacity external mechanism 210 ± 30 ml (7.1 ± 1.01 fl. oz.) Fork oil (SAE 4) (48601166S1) right p. 130) Grease capacity, left cartridge 5 g (0.18 oz) Multi-purpose grease (00062010051) ( p. 131) Oil capacity, right cartridge 380 ml (12.85 fl.

  • Page 128: 125/150 Sx Us

    20 TECHNICAL DATA 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 129: Carburetor - Adjusting The Idle Chassis Tightening Torques

    TECHNICAL DATA 20 20.9 Chassis tightening torques Screw, kill switch 1 Nm (0.7 lbf ft) Screw, fixed grip 5 Nm (3.7 lbf ft) Loctite ® 243™ Screw, service hour counter 1 Nm (0.7 lbf ft) Spoke nipple, front wheel M4.5 6 Nm (4.4 lbf ft) Spoke nipple, rear wheel M4.5...
  • Page 130 20 TECHNICAL DATA Remaining nuts, chassis 45 Nm (33.2 lbf ft) Remaining screws, chassis 45 Nm (33.2 lbf ft) Screw, bottom shock absorber 60 Nm (44.3 lbf ft) Loctite ® 2701™ Screw, handlebar support 40 Nm (29.5 lbf ft) Loctite ®...

  • Page 131: Substances

    SUBSTANCES 21 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 132 21 SUBSTANCES Recommended supplier Motorex ® – Cross Power 2T Fork oil (SAE 4) (48601166S1) Standard/classification – SAE ( p. 133) (SAE 4) Guideline – Use only oils that comply with the specified standards (see specifications on the container) and that exhibit the corresponding properties.

  • Page 133: Auxiliary Substances

    AUXILIARY SUBSTANCES 22 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 134 22 AUXILIARY SUBSTANCES Preserving materials for paints, metal and rubber Recommended supplier Motorex ® – Moto Protect Special cleaner for glossy and matte paint finishes, metal and plastic surfaces Recommended supplier Motorex ® – Quick Cleaner Universal oil spray Recommended supplier Motorex ®...

  • Page 135: Checking The Basic Position Of The

    STANDARDS 23 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 136: List Of Abbreviations

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

  • Page 137: Index

    INDEX Chain tension INDEX adjusting ......68 Accessories ......9 checking .
  • Page 138 INDEX article number ..... . 13 basic setting, checking ....40 Lower triple clamp Fork legs installing .
  • Page 139 INDEX removing ......58 Tire condition checking ......93 Service .
  • Page 140 *3213847en* 3213847en 03/2018 KTM Sportmotorcycle GmbH 5230 Mattighofen/Austria Photo: Mitterbauer/KTM http://www.ktm.com...

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