KTM 50 SX 2020 Owner's Manual
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KTM 50 SX 2020 Owner's Manual

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OWNER'S MANUAL
2020
50 SX
50 SX Mini
Art. no. 3213996en

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Summary of Contents for KTM 50 SX 2020

  • Page 1 OWNER'S MANUAL 2020 50 SX 50 SX Mini Art. no. 3213996en...
  • 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 Running in the engine ...... 21 TABLE OF CONTENTS MEANS OF REPRESENTATION ...... 5 RIDING INSTRUCTIONS......22 Symbols used ........5 Formats used........5 Checks and maintenance measures when preparing for use ..... 22 SAFETY ADVICE..........6 Starting the vehicle ......
  • Page 5 TABLE OF CONTENTS 11.2 Removing the motorcycle from the 12.2 Adjusting the play of the hand brake lift stand ......... 41 lever ..........71 11.3 Bleeding the fork legs....... 41 12.3 Adjusting the basic position of the hand brake lever ......71 11.4 Cleaning the dust boots of the fork legs ..........
  • Page 6 TABLE OF CONTENTS 16 SERVICE WORK ON THE ENGINE ....105 16.1 Checking oil level (50 SX Mini) ..105 16.2 Bleeding the oil pump (50 SX Mini) ......... 105 16.3 Checking the gear oil level ....106 16.4 Changing the gear oil ....

  • Page 7: Means Of Representation 1

    All work marked with this symbol requires specialist knowledge and technical understanding. In the interest of the safety of your child, have these jobs performed in an authorized KTM work- shop. There, your motorcycle will be optimally cared for by specially trained experts using the specialist tools required.

  • Page 8: Safety Advice

    2 SAFETY ADVICE Use definition – intended use This vehicle has been designed and built to withstand the normal stresses and strains of racing. This vehicle com- plies 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

    – When you ride a motorcycle, set an example for your child and wear suitable protective clothing. In the interest of your own safety, KTM recommends that you only operate the vehicle while wearing suitable pro- tective clothing. Work rules Special tools are necessary for certain tasks.
  • Page 11 SAFETY ADVICE 2 The Owner's Manual is also available for download from your authorized KTM dealer and on the KTM website. International KTM Website: http://www.ktm.com...

  • Page 12: Important Notes

    Manufacturer and 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 13: View Of Vehicle 4

    VIEW OF VEHICLE 4 View of vehicle, front left (example) F02182-10 Fuel tank filler cap Quick release of seat Chain guide Plug-in stand ( p. 18) Choke Fuel tap ( p. 17)

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

    4 VIEW OF VEHICLE View of vehicle, rear right (example) F02183-10 Kill switch ( p. 15) Throttle grip ( p. 15) Hand brake lever ( p. 15) Vehicle identification number ( p. 13) Kick starter lever ( p. 18) Foot brake lever ( p.

  • Page 15: Serial Numbers 5

    SERIAL NUMBERS 5 Vehicle identification number The vehicle identification number is stamped on the right side of the steering head. 401945-10 Type label (50 SX) The type label is located on the front frame tube. 402154-10 (50 SX Mini) Type label is fixed to the front of the steering head.

  • Page 16: Fork Part Number

    5 SERIAL NUMBERS Fork part number The fork part number is stamped on the outside of the axle clamp. 401947-10 Shock absorber article number (50 SX) The shock absorber article number is stamped on the bot- tom of the shock absorber toward the right-hand side. H01186-10 (50 SX Mini) The shock absorber article number...

  • Page 17: Controls 6

    CONTROLS 6 Hand brake lever Hand brake lever is fitted on the right side of the handlebar. The hand brake lever is used to activate the front brake. K01119-11 Throttle grip Throttle grip is fitted on the right side of the handlebar. K01119-10 Kill switch Kill switch...

  • Page 18: Closing The Fuel Tank Filler Cap

    6 CONTROLS Warning Danger of poisoning Fuel is poisonous and a health hazard. – Avoid skin, eye and clothing contact with fuel. – Immediately consult a doctor if you swallow fuel. – Do not inhale fuel vapors. – In case of skin contact, rinse the affected area with plenty of water. –...

  • Page 19: Closing Oil Tank Cap (50 Sx Mini)

    CONTROLS 6 Closing oil tank cap (50 SX Mini) – Put the oil tank cap on and turn it clockwise. Info Run the oil tank breather hose without kinks. V00253-11 Fuel tap Fuel tap is on the left of the fuel tank. Possible states Fuel tap is closed –...

  • Page 20: Kick Starter Lever

    6 CONTROLS Possible states Choke function activated – The choke lever is pushed up all • the way to the stop. Choke function deactivated – The choke lever is pushed down • all the way to the stop. 6.11 Kick starter lever Kick starter lever is fitted on the right side of the engine.

  • Page 21: Preparing For Use 7

    PREPARING FOR USE 7 Advice on preparing for first use Warning Danger of accidents A lack of physical and mental readiness on the part of the child poses a major risk. Children often underestimate or fail to recognize dangerous situations. – Your child must already be able to ride a bicycle.
  • Page 22 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 23: Running In The Engine

    PREPARING FOR USE 7 Running in the engine – During the running-in phase, do not exceed the specified engine performance. Guideline Maximum engine performance During the first 3 operating hours < 70 % During the first 5 operating hours < 100 % –...

  • Page 24: 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 25: Starting Off

    Open the throttle carefully. Riding Info If unusual noises occur while riding, stop immediately, switch off the engine and contact an authorized KTM workshop. – If the choke function has been activated, deactivate it after the engine has warmed up. –...

  • Page 26: 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 allow your child to 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 27: Transporting

    RIDING INSTRUCTIONS 8 Transporting Note Danger of damage The parked vehicle can roll away or fall over. – Park the vehicle on a firm and level surface. Note Fire hazard Hot vehicle components pose a fire hazard and explosion risk. – Do not park the vehicle near to materials which are highly flammable or explosive. –...

  • Page 28: Filling Up With Oil (50 Sx Mini)

    8 RIDING INSTRUCTIONS – Fill the fuel tank with fuel up to measurement Guideline 35 mm (1.38 in) Measurement of Fuel tank capacity, 2.1 l (2.2 qt.) Super unleaded approx. (50 SX Mini) (ROZ 95/RON 95/PON 91) p. 131) Fuel tank capacity, 2.3 l (2.4 qt.) Super unleaded 400214-10...

  • Page 29: Service Schedule 9

    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 30: Recommended Work

    ● ● Final check: Check the vehicle for safe operation and take a test ride. ○ ● ● ● Make a service entry in the KTM Dealer.net. ○ One-time interval ● Periodic interval Recommended work Every 80 operating hours Once after 20 operating hours / Every 20 operating hours...

  • Page 31: Tuning The Chassis 10

    – As delivered, KTM offroad motorcycles are adjusted for an average rider's weight (with full protective clothing). Guideline Standard rider weight 25 …...

  • Page 32: Compression Damping Of The Shock Absorber (50 Sx)

    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 33: Adjusting The High-Speed Compression Damping Of The Shock Absorber (50 Sx)

    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 34 10 TUNING THE CHASSIS Guideline Rebound damping Comfort 17 clicks Standard 15 clicks Sport 13 clicks Info Turn clockwise to increase the damping; turn coun- terclockwise to reduce the damping. (50 SX Mini) – Raise the motorcycle with a lift stand. ( p.

  • Page 35: Measuring The Rear Wheel Dimension Unloaded

    TUNING THE CHASSIS 10 – Position the shock absorber and rear wheel. – Mount and tighten screw and nut Guideline Screw, bottom 45 Nm (33.2 lbf ft) Loctite ® 243™ shock absorber – Remove the motorcycle from the lift stand. ( p.

  • Page 36: Checking The Riding Sag 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.) Preparatory work (50 SX) –...
  • Page 37 TUNING THE CHASSIS 10 – Tighten the spring to the specified measurement by turn- ing adjusting ring Guideline Spring preload 3 mm (0.12 in) Info The spring preload is the difference between the relaxed spring length and the tensioned spring length.

  • Page 38: Adjusting The Riding Sag

    10 TUNING THE CHASSIS 10.11 Adjusting the riding sag Preparatory work (50 SX) – Raise the motorcycle with a lift stand. ( p. 41) (50 SX Mini) – Raise the motorcycle with a lift stand. ( p. 41) – Remove the rear wheel. p.

  • Page 39: Checking The Basic Setting Of The Fork

    TUNING THE CHASSIS 10 10.12 Checking the basic setting of the fork Info For various reasons, no exact riding sag can be determined for the fork. (50 SX) – Smaller differences in the rider's weight can be compen- sated for by the fork air pressure. –...

  • Page 40: Adjusting The Rebound Damping Of The Fork (50 Sx)

    10 TUNING THE CHASSIS 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...

  • Page 41: Handlebar Position

    TUNING THE CHASSIS 10 Info Turn clockwise to increase the damping; turn counter- clockwise to reduce the damping. 10.15 Handlebar position On the upper triple clamp, there are 2 holes at a distance of each other. 15 mm (0.59 in) Hole distance The holes on the handlebar support are placed at a distance of from the center.

  • Page 42: Adjusting The Seat Height

    10 TUNING THE CHASSIS Info Make sure the installed gaps are even. 10.17 Adjusting the seat height Warning Danger of accidents Modifications to the suspension setting may seriously alter the handling characteris- tic. – Ride slowly to start with after making adjustments to get the feel of the new handling characteristic. Preparatory work –...

  • Page 43: Service Work On The Chassis 11

    SERVICE WORK ON THE CHASSIS 11 11.1 Raising the motorcycle with a lift stand Note Danger of damage The parked vehicle can roll away or fall over. – Park the vehicle on a firm and level surface. – Raise the motorcycle at the frame underneath the engine. Lift stand (78929955100) Neither wheel is in contact with the ground.

  • Page 44: Cleaning The Dust Boots Of The Fork Legs

    11 SERVICE WORK ON THE CHASSIS (50 SX Mini) – Release bleeder screws Any excess pressure escapes from the interior of the fork. – Tighten the bleeder screws. F02192-10 Finishing work – Remove the motorcycle from the lift stand. ( p.

  • Page 45: Removing The Fork Protector

    SERVICE WORK ON THE CHASSIS 11 11.5 Removing the fork protector – Remove screws and take off the clamp. – Remove screws on the left fork leg. Take off the fork pro- tector. V00266-10 – Remove screws on the right fork leg. Take off the fork pro- tector.

  • Page 46: Removing The Fork Legs

    11 SERVICE WORK ON THE CHASSIS 11.7 Removing the fork legs Preparatory work – Raise the motorcycle with a lift stand. ( p. 41) – Remove the front wheel. p. 87) Main work – Remove screws and take off the clamp. –...
  • Page 47 SERVICE WORK ON THE CHASSIS 11 – Tighten screws Guideline Screw, top triple 20 Nm clamp (14.8 lbf ft) – Tighten screws Guideline Screw, bottom 15 Nm triple clamp (11.1 lbf ft) V00269-11 (50 SX Mini) – Position the fork legs. Bleeder screws are positioned toward the rear.

  • Page 48: Removing The Lower Triple Clamp

    11 SERVICE WORK ON THE CHASSIS 11.9 Removing the lower triple clamp Preparatory work – Raise the motorcycle with a lift stand. ( p. 41) – Remove the front wheel. p. 87) – Remove the fork legs. p. 44) – Remove the start number plate.
  • Page 49 SERVICE WORK ON THE CHASSIS 11 – Position the upper triple clamp with the handlebar. – Mount nut , but do not tighten it yet. V00282-10 (50 SX) – Position the fork legs. Bleeder screws are positioned toward the rear. Info The second milled groove (from the top) must be flush with the upper edge of the upper triple clamp.
  • Page 50 11 SERVICE WORK ON THE CHASSIS (50 SX Mini) – Position the fork legs. Bleeder screws are positioned toward the rear. Info The second milled groove (from the top) must be flush with the upper edge of the upper triple clamp. F02192-11 –...

  • Page 51: Checking The 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 52: Adjusting The Steering Head Bearing Play

    11 SERVICE WORK ON THE CHASSIS 11.12 Adjusting the steering head bearing play Preparatory work – Raise the motorcycle with a lift stand. ( p. 41) Main work (50 SX) – Pull fuel tank breather out of the steering stem. –...

  • Page 53: Greasing The Steering Head Bearing

    SERVICE WORK ON THE CHASSIS 11 11.13 Greasing the steering head bearing – Remove the lower triple clamp. p. 46) – Install the lower triple clamp. p. 46) H02387-01 11.14 Removing 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 54: Installing The Fuel Tank

    11 SERVICE WORK ON THE CHASSIS – Raise the fuel tank. – Pull off fuel hose Info Remaining fuel may flow out of the fuel hose. – Pull fuel tank breather out of the steering stem. – Take off the fuel tank. R00531-10 11.15 Installing the fuel tank...

  • Page 55: Removing The Start Number Plate

    SERVICE WORK ON THE CHASSIS 11 – Position the fuel tank. – Make sure that no cables or throttle cables are trapped or dam- aged. – Mount and tighten screw Guideline Remaining screws, 10 Nm (7.4 lbf ft) chassis – Position the fuel tank breather in the steering stem.

  • Page 56: Removing Front Fender

    11 SERVICE WORK ON THE CHASSIS 11.18 Removing front fender – Remove screws . Take off the front fender. H01428-10 11.19 Installing front fender – Position the fender with drill holes in the holding lugs on the start number plate. H00064-10 –...

  • Page 57: Installing The Shock Absorber

    SERVICE WORK ON THE CHASSIS 11 – Remove screw , push splash protector to the side, and remove the shock absorber. F02196-10 (50 SX Mini) – Remove nut V00279-10 – Remove screw and lower the link fork carefully. – Remove screw , push splash protector to the side, and remove the shock absorber.

  • Page 58: Removing The Seat

    11 SERVICE WORK ON THE CHASSIS – Raise the link fork, mount and tighten the shock absorber with screw Guideline Screw, bottom 45 Nm (33.2 lbf ft) Loctite ® 243™ shock absorber – Mount nut and tighten the fitting. Guideline Screw, top 45 Nm (33.2 lbf ft) F02195-11...

  • Page 59: Mounting The Seat

    SERVICE WORK ON THE CHASSIS 11 11.23 Mounting the seat – Hook the seat onto screw , lower the seat at the rear, and push it forward. Holding lug hooks into the fuel tank. H01431-10 – Close quick release H00066-11 11.24 Removing the air filter Note...

  • Page 60: Installing The Air Filter

    11 SERVICE WORK ON THE CHASSIS 11.25 Installing the air filter Main work – Position the clean air filter. – Position the rear holding lug. Lower the air filter box cover and allow the front holding lug to snap in. Info If the air filter is not mounted correctly, dust and dirt may enter the engine and result in damage.

  • Page 61: Removing The Main Silencer

    SERVICE WORK ON THE CHASSIS 11 11.27 Removing 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. –...

  • Page 62: Removing The Engine Sprocket Cover

    11 SERVICE WORK ON THE CHASSIS Main work – Remove screws with toothed washers from the silencer – Remove end cap and outer tube – Remove glass fiber yarn filling from the inner tube. – Clean the parts that need to be reinstalled and check for dam- age.

  • Page 63: Installing The Engine Sprocket Cover

    SERVICE WORK ON THE CHASSIS 11 11.31 Installing the engine sprocket cover Main work (50 SX) – Position the engine sprocket cover. Mount screws , but do not tighten yet. – Mount and tighten screw Guideline Screw, engine 12 Nm (8.9 lbf ft) sprocket cover H01437-10 –...

  • Page 64: Cleaning The Chain

    11 SERVICE WORK ON THE CHASSIS 11.33 Cleaning the chain Warning Danger of accidents Lubricants on the tires reduces the road grip. – Remove lubricants from the tires using a suitable cleaning agent. Warning Danger of accidents Oil or grease on the brake discs reduces the braking effect. –...

  • Page 65: Adjusting The Chain Tension

    SERVICE WORK ON THE CHASSIS 11 Main work (50 SX) – Press the chain upward at the end of the chain sliding piece and determine chain tension Info The top part of chain must be taut. Chain wear is not always even, so you should repeat this measurement at different chain positions.
  • Page 66 11 SERVICE WORK ON THE CHASSIS Main work (50 SX) – Loosen nut – Loosen nuts – Adjust the chain tension by turning adjusting screws left and right. Guideline Chain tension 5 … 8 mm (0.2 … 0.31 in) F02198-10 Turn the adjusting screws on the left and right so that the markings on the left and right chain...

  • Page 67: Checking The Chain, Rear Sprocket, Engine Sprocket, And Chain Guide

    SERVICE WORK ON THE CHASSIS 11 11.36 Checking the chain, rear sprocket, engine sprocket, and chain guide Preparatory work – Raise the motorcycle with a lift stand. ( p. 41) – Remove the engine sprocket cover. p. 60) Main work –...
  • Page 68 11 SERVICE WORK ON THE CHASSIS (50 SX) – Check the chain sliding guard for wear. » If the ridge is worn down to the level of the main cor- pus: – Change the chain sliding guard. – Check that the chain sliding guard is firmly seated. »...
  • Page 69 SERVICE WORK ON THE CHASSIS 11 – Check that the chain guide is firmly seated. » If the chain guide is loose: – Tighten the screws on the chain guide. Guideline Remaining 10 Nm screws, chassis (7.4 lbf ft) F02201-01 (50 SX Mini) –...

  • Page 70: Adjusting The Chain Guide

    11 SERVICE WORK ON THE CHASSIS – Check the chain guide for wear. Info Wear can be seen on the front of the chain guide. » If the light part of the chain guide is worn: – Change the chain guide. 400985-01 –...

  • Page 71: Checking The Frame

    If the link fork shows signs of damage, cracking, or deformation: – Change the link fork. Info Always replace a damaged link fork. Repair- ing the link fork is not authorized by KTM. F02202-01 (50 SX Mini) – Check the link fork for damage, cracking, and deformation. »...

  • Page 72: Checking The Rubber Grip

    11 SERVICE WORK ON THE CHASSIS Main work – Check the throttle cable routing. The throttle cable must be routed to the carburetor behind the handlebars and above the fuel tank bracket. » If the throttle cable routing is not as specified: –...

  • Page 73: Brake System 12

    BRAKE SYSTEM 12 12.1 Checking play of handbrake lever Warning Danger of accidents The brake system fails in the event of overheating. If there is no free travel on the hand brake lever, pressure builds up on the front brake circuit. –...

  • Page 74: 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.) – Check the front and rear brake disc thickness at multiple...

  • Page 75: 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.) Note Environmental hazard Hazardous substances cause environmental damage.

  • Page 76: Adding The 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 77: 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 78 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 79 BRAKE SYSTEM 12 – Remove screw – Press back the brake linings by slightly tilting the brake caliper laterally on the brake disc. Carefully pull the brake caliper backward from 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 80: Checking The Free Travel Of The Foot Brake Lever

    12 BRAKE SYSTEM Guideline Screw, front M8x60 20 Nm (14.8 lbf ft) Loctite ® 243™ brake caliper – Tighten screw Guideline Screw, front M8x40 20 Nm (14.8 lbf ft) Loctite ® 243™ brake caliper – Remove the locking piece of the hand brake lever. –...

  • Page 81: Adjusting The Free Travel Of The Foot Brake Lever

    BRAKE SYSTEM 12 12.10 Adjusting the free travel of the 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 82: 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.) – Stand the vehicle upright.
  • Page 83 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 84: 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.) (50 SX) – Check the brake linings for minimum thickness ≥...
  • Page 85 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 86 12 BRAKE SYSTEM – Remove screws – Take off cover with washer and membrane – Press the brake piston back into the basic position and ensure that brake fluid does not flow out of the brake fluid reservoir; extract some if necessary. F02208-10 –...
  • Page 87 BRAKE SYSTEM 12 – Take off the brake caliper and pull the brake line out of holder Info Do not kink or damage the brake line. – Remove the brake linings. – Clean the brake caliper and the brake caliper bracket. –...
  • Page 88 12 BRAKE SYSTEM – Operate the foot brake lever repeatedly until the brake lin- ings are in contact with the brake disc and there is a pressure point. – Add brake fluid up to level Guideline 10 mm (0.39 in) Level (brake fluid level below reservoir rim)

  • Page 89: Wheels, Tires 13

    WHEELS, TIRES 13 13.1 Removing the front wheel Preparatory work – Raise the motorcycle with a lift stand. ( p. 41) Main work – Remove screw – Loosen screws H01451-10 Warning Danger of accidents Damaged brake discs reduce the braking effect. –...

  • Page 90: Removing The Rear Wheel

    13 WHEELS, TIRES – Check the wheel bearing for damage and wear. » If the wheel bearing is damaged or worn: – Change front wheel bearing. – Clean and grease the contact surfaces of the spacers. Long-life grease ( p. 132) –...
  • Page 91 WHEELS, TIRES 13 – Pull out wheel spindle far enough to allow the rear wheel to be pushed forward. – Push the rear wheel forward as far as possible. Remove the chain from the rear sprocket. Info Cover the components to protect them against dam- age.

  • Page 92: Installing The Rear Wheel

    13 WHEELS, TIRES Info Do not operate the foot brake lever when the rear wheel is removed. – Remove spacers F02175-11 13.4 Installing the rear wheel Warning Danger of accidents Oil or grease on the brake discs reduces the braking effect. –...

  • Page 93: Checking The Tire Condition

    Checking the tire condition Info Only mount tires approved and/or recommended by KTM. Other tires could have a negative effect on handling characteristics. The type, condition, and pressure of the tires all have a major impact on the handling characteristic of the motorcycle.

  • Page 94: Checking Tire Pressure

    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 H01144-10 wear.

  • Page 95: 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 96: 14 Cooling System

    14 COOLING SYSTEM 14.1 Cooling system The water pump in the engine forces the coolant to flow. The pressure resulting from the warming of the cooling system is regulated by a valve in the radiator cap . This ensures that operating the vehicle at the specified coolant temperature will not result in a risk of malfunctions.

  • Page 97: Checking The Coolant Level

    COOLING SYSTEM 14 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 98: Refilling With Coolant

    14 COOLING SYSTEM 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 99 COOLING SYSTEM 14 – Move the vehicle into the position shown and prevent it from rolling away. Height difference must be reached. Guideline 50 cm (19.7 in) Height difference Info For all of the air to be able to escape from the cooling system, the vehicle must be raised at the front.

  • Page 100: 15 Tuning The Engine

    15 TUNING THE ENGINE 15.1 Checking the installation position of the throttle grip Warning Danger of accidents The throttle cable may slip out of the guide if the throttle grip installation position is incorrect. The throttle slide will then no longer be closed and the speed can no longer be controlled. –...

  • Page 101: Adjusting The Throttle Cable Play

    TUNING THE ENGINE 15 15.3 Adjusting the throttle cable play Preparatory work – Check the installation position of the throttle grip. ( p. 98) – Remove the seat. ( p. 56) – Turn the knurled screw on the fuel tap all the way clockwise. –...

  • Page 102: Carburetor - Idle Setting

    15 TUNING THE ENGINE Carburetor – idle setting (50 SX Mini) 15.5 The idle setting of the carburetor has a big influence on the start- ing behavior, stable idle speed, and the response to throttle open- ing. This means that an engine with a correctly set idle speed will be easier to start than one with an incorrectly set idle speed.

  • Page 103: (50 Sx Mini)

    TUNING THE ENGINE 15 Info If there is a big engine speed rise, reduce the idle speed to a normal level and repeat the above steps. If the procedure described here does not lead to sat- isfactory results, the cause may be a wrongly dimen- sioned idling jet.

  • Page 104: Checking The Clutch Setting

    15 TUNING THE ENGINE Info If there is a big engine speed rise, reduce the idle speed to a normal level and repeat the above steps. If the procedure described here does not lead to sat- isfactory results, the cause may be a wrongly dimen- sioned idling jet.

  • Page 105: Removing The Clutch Cover

    TUNING THE ENGINE 15 15.9 Removing the clutch cover Note Environmental hazard Improper handling of fuel is a danger to the environment. – Do not allow fuel to enter the groundwater, the soil, or the sewage system. Info Fuel can emerge via the carburetor. Capture emerging fuel using a suitable container.

  • Page 106: Installing The Clutch Cover

    15 TUNING THE ENGINE Guideline 1 click increases the slip 250 … 350 rpm speed by Info The springs may not be pretensioned by more than 17 clicks from the stop using the adjusting screws. Condition If the slip speed is too high: –...

  • Page 107: Service Work On The Engine 16

    SERVICE WORK ON THE ENGINE 16 16.1 Checking oil level (50 SX Mini) Preparatory work – Stand the motorcycle upright on a horizontal surface. Main work – Check the oil level in the oil tank. For a full fuel tank, the oil tank must be filled up toMIN mark at a minimum.

  • Page 108: Checking The Gear Oil Level

    16 SERVICE WORK ON THE ENGINE – Remove screws – Take off the oil pump. – Pull off oil line from the carburetor. 300651-10 – Turn oil pump gear wheel counterclockwise until oil flows out of oil line without bubbles. V00276-10 –...

  • Page 109: Changing The Gear Oil

    SERVICE WORK ON THE ENGINE 16 (50 SX Mini) – Remove screw – Check the gear oil level. A small quantity of gear oil must run out of the drilled hole. » If no gear oil runs out: – Add the gear oil. p.

  • Page 110: Adding The Gear Oil

    16 SERVICE WORK ON THE ENGINE (50 SX Mini) – Place an appropriate container under the engine. – Remove oil drain plug with the magnet. – Let the gear oil drain fully. – Thoroughly clean the oil drain plug with magnet. –...
  • Page 111 SERVICE WORK ON THE ENGINE 16 Main work (50 SX) – Remove gear oil level monitoring screw H00083-10 (50 SX Mini) – Remove gear oil level monitoring screw S00882-10 – Remove filler plug with the O-ring. – Add gear oil until it flows out of the hole of the gear oil level plug.

  • Page 112: 17 Carburetor

    17 CARBURETOR 17.1 Removing the carburetor (50 SX Mini) 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 113: Removing The Carburetor (50 Sx)

    CARBURETOR 17 – Loosen hose clip – Loosen hose clip – Pull the carburetor out of the intake flange. – Pull the carburetor forward out of the inlet sleeve. T00392-10 – Remove screw – Take off the throttle slide cover and pull the throttle slide out of the carburetor.
  • Page 114 17 CARBURETOR Preparatory work – Turn the knurled screw on the fuel tap all the way clockwise. Main work – Pull off fuel hose Info Remaining fuel may flow out of the fuel hose. R00564-10 – Loosen hose clip – Loosen hose clip R04489-10 –...

  • Page 115: Installing The Carburetor (50 Sx Mini)

    CARBURETOR 17 17.3 Installing the carburetor (50 SX Mini) Main work – Attach throttle cable wire 300903-10 – Position spring retainer – Position the throttle slide spring. 300902-11 – Position the throttle slide and throttle slide cover. – Mount and tighten screw Guideline Screw, throttle slide 3 Nm (2.2 lbf ft)

  • Page 116: Installing The Carburetor (50 Sx)

    17 CARBURETOR – Connect fuel hose T00390-11 Finishing work – Bleed the oil pump. p. 105) – Check the throttle cable play. ( p. 98) – Carburetor – adjust the idle speed. p. 101) 17.4 Installing the carburetor (50 SX) Main work –...
  • Page 117 CARBURETOR 17 – Mount the carburetor. – Mount the engine breather hose and position clamp R00566-11 – Mount the inlet sleeve. – Position and tighten hose clip – Position and tighten hose clip R04489-11 – Mount fuel hose R00564-11 Finishing work –...

  • Page 118: 18 Cleaning, Care

    18 CLEANING, CARE 18.1 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 119 CLEANING, CARE 18 Info The heat produced causes water at inaccessible loca- tions in the engine and on the brake system to evapo- rate. – Push back the protection caps on the handlebar controls to allow water to evaporate. – After the motorcycle has cooled off, lubricate all moving parts and pivot points.

  • Page 120: 19 Storage

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

  • Page 121: Preparing For Use After Storage

    STORAGE 19 19.2 Preparing for use after storage – Remove the motorcycle from the lift stand. ( p. 41) – Perform checks and maintenance measures when preparing for use. ( p. 22) – Take a test ride. 401059-01...

  • Page 122: 20 Troubleshooting

    20 TROUBLESHOOTING Faults Possible cause Action – Engine turns but does not start Operating error Carry out the start procedure. p. 22) – Motorcycle was out of use for a Empty the carburetor float chamber. long time and there is old fuel in the float chamber –...
  • Page 123 TROUBLESHOOTING 20 Faults Possible cause Action Engine does not speed up The carburetor is flowing over (50 SX) – Check/set the carburetor compo- because the float needle is nents. dirty or worn (50 SX Mini) – Check/set the carburetor compo- nents.
  • Page 124 20 TROUBLESHOOTING Faults Possible cause Action – Engine overheats Bent radiator hose Change the radiator hose. – White smoke emission (steam Damaged cylinder head or Check the cylinder head or cylinder in exhaust gas) cylinder head gasket head gasket. – Gear oil exits at the vent hose Too much gear oil added Check the gear oil level.

  • Page 125: Technical Data 21

    TECHNICAL DATA 21 21.1 Engine Design 1-cylinder 2-stroke engine, water-cooled, with reed intake Displacement 49.0 cm³ (2.99 cu in) Stroke 40 mm (1.57 in) Bore 39.5 mm (1.555 in) Crankshaft bearing 2 grooved ball bearings Conrod bearing Needle bearing Piston pin bearing Needle bearing Pistons Aluminum cast...

  • Page 126: Carburetor With Carburetor Tuning

    21 TECHNICAL DATA Screw, ignition coil 4 Nm (3 lbf ft) Loctite ® 243™ Screw, intake flange 5 Nm (3.7 lbf ft) Loctite ® 243™ Screw, pressure plate 10 Nm (7.4 lbf ft) Loctite ® 243™ Screw, water pump cover 10 Nm (7.4 lbf ft) Screw, cylinder head 18 Nm (13.3 lbf ft)

  • Page 127: Capacities

    TECHNICAL DATA 21 21.4 Capacities 21.4.1 Gear oil Gear oil 0.20 l (0.21 qt.) Gear oil (ATF Dexron 3) ( p. 131) 21.4.2 Coolant Coolant 0.7 l (0.7 qt.) Coolant ( p. 130) 21.4.3 Fuel Fuel tank capacity, approx. 2.3 l (2.4 qt.) Super unleaded (95 octane) mixed (50 SX) with 2-stroke engine oil (1:60)

  • Page 128: Tires

    2.75 - 10 38J TT Maxxis MAXX CROSS SI Maxxis MAXX CROSS SI The tires specified represent one of the possible series production tires. Additional information is available in the Service section under: http://www.ktm.com 21.7 Fork 21.7.1 50 SX Fork article number 07.18.6T.02...

  • Page 129: Shock Absorber

    TECHNICAL DATA 21 Weight of rider: 15 … 25 kg (33 … 55 lb.) 1.8 N/mm (10.3 lb/in) Weight of rider (standard): 25 … 35 kg (55 … 2.0 N/mm (11.4 lb/in) 77 lb.) Weight of rider: 35 … 45 kg (77 … 99 lb.) 2.2 N/mm (12.6 lb/in) Spring length with preload spacer(s) 337.5 mm (13.287 in)

  • Page 130: Chassis Tightening Torques

    21 TECHNICAL DATA Standard 5 mm (0.2 in) Spring rate Weight of rider: 15 … 25 kg (33 … 55 lb.) 65 N/mm (371 lb/in) Weight of rider (standard): 25 … 35 kg (55 … 75 N/mm (428 lb/in) 77 lb.) Weight of rider: 35 …...
  • Page 131 TECHNICAL DATA 21 Screw, front brake caliper M8x60 20 Nm (14.8 lbf ft) Loctite ® 243™ Screw, front brake caliper M8x40 20 Nm (14.8 lbf ft) Loctite ® 243™ Screw, handlebar clamp 20 Nm (14.8 lbf ft) Screw, rear sprocket 25 Nm (18.4 lbf ft) Loctite ®...

  • Page 132: 22 Substances

    22 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 133 SUBSTANCES 22 Gear oil (ATF Dexron 3) Standard/classification – Dexron III (ATF Dexron 3) Guideline – Use only ATF gear oils that comply with the specified standards (see specifications on the container) and that possess the necessary properties. Recommended supplier MOTOREX ®...

  • Page 134: 23 Auxiliary Substances

    23 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 135 Preserving materials for paints, metal and rubber Recommended supplier MOTOREX ® – Moto Protect Rubber grip adhesive (00062030051) Recommended supplier KTM AG – GRIP GLUE Special cleaner for glossy and matte paint finishes, metal and plastic surfaces Recommended supplier MOTOREX ® –...

  • Page 136: 24 Standards

    24 STANDARDS JASO FD JASO FD is a classification for a 2-stroke engine oil that was specifically developed for the extreme demands of racing. Thanks to first-rate synthetic esters and specially designed additives, superb combustion is achieved even under extreme operating conditions. The SAE viscosity classes were defined by the Society of Automotive Engineers and are used for classifying oils according to their viscosity.

  • Page 137: List Of Abbreviations 25

    LIST OF ABBREVIATIONS 25 Art. no. Article number circa compare e.g. for example etc. et cetera i.a. inter alia number poss. possibly...

  • Page 138: Index

    INDEX Choke ......17 INDEX Cleaning ......116-117 Accessories .
  • Page 139 INDEX Front fender removing ......59 installing ......54 Manufacturer warranty .
  • Page 140 INDEX Service ......10 Service hour counter ..... 18 Vehicle identification number .
  • Page 141 *3213996en* 3213996en 03/2019 KTM Sportmotorcycle GmbH 5230 Mattighofen/Austria Photo: Mitterbauer/KISKA/KTM http://www.ktm.com...

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