KTM may stop manufactur- ing certain models without previous notice. KTM shall not be held liable for any deviations of availabil- ity and/or ability to deliver, illustrations, descriptions, printing and/or other errors. The illustrated models partly contain extra equipment, which is not applied to standard models.
IMPORTANT INFORMATION INTENDED PURPOSE KTM mini-sports motorcycles are designed and constructed to resist the usual wear and tear of normal use in competitions. The motorcycles comply with the regulations and categories currently in effect with the leading interna- tional motorcycle associations.
SPARE PARTS, ACCESSORIES For the safety of your child, only use spare parts and accessories approved by KTM. KTM shall not assume any liability for other products or consequential damage resulting from the use of such products.
IMPORTANT INFORMATION FOR PARENTS ABOUT SAFE DRIVING KTM mini motorcycles are off-road motorcycles designed for one person only. They are not allowed on public roads. The vehicle dimensions and components are designed for children from 4 to 10 years of age with a maximum weight of.
» SERIAL NUMBER LOCATIONS Chassis number The chassis number is located on the type plate on the steering head. Enter this number in the field on page no 1. Engine number The engine number is stamped into the right half of the engine case next to the kickstarter.
Install tank breather hose  without kinks. Fuel tap The fuel tap  is located at the front of the motorcycle on the left side of the tank. Opening the fuel tap: Turn the knob all the way to the left.
Moving the choke lever back closes the hole in the carburetor again. Choke Dell’Orto carburetor PHBG 19 BS (50 SX) Choke control knob  is mounted to the left side of the carburetor. If you pull the choke control knob up to the stop and turn it 90º, a hole is opened...
– Only use accessory parts recommended by KTM. – Never leave your motorcycle without supervision as long as the engine is running. – KTM mini models are designed for one person only. Passengers are not allowed. – These models do not comply with the regulations and safety standards established by the law.
If the brake fluid falls below the minimum level, the brake system is either leaking or the brake shoes are completely worn out. Have the brake system checked at a KTM workshop to avoid brake failure. Also have the condition of the brake hose and the brake lining thickness checked.
The highly inflammable components in modern fuels volatilize if left stand- ing for longer periods of time. If the motorcycle has not been used for over 1 week, the fuel should be drained from the float chamber. The engine will...
– If the resistance of the hand brake lever feels unresponsive, something is wrong with the brake system. Have the brake sys- tem checked at a KTM workshop before you let your child drive the motorcycle. Stopping Reduce the speed.
PERIODIC MAINTENANCE SCHEDULE 50 SX JUNIOR 50 SX A CLEAN MOTORCYCLE CAN BE CHECKED MORE QUICKLY WHICH SAVES MONEY! Check engine for leaks Change transmission oil Check spark plug, change it if necessary, set electrode gap Check the clutch engagement speed...
If the inspection establishes that permissible tolerances are exceeded, the respective components must be replaced. The kilometer reading for inspection intervals should not exceed 5 hours. Maintenance work performed by your authorized KTM workshop is not a substitute for care and maintenance by the driver! NOTE: A service hour counter (item no.: SXS05450600) is available from your KTM dealer for strict observance of the service...
Maintenance work and adjustments marked with an asterisk (*) must be performed by an expert. To protect your youngster, always have such work performed by a specialized KTM dealer where your motorcycle will be optimally serviced by appropriately qualified, skilled staff.
MAINTENANCE WORK ON CHASSIS AND ENGINE 3,5 mm Checking and adjusting the steering head bearing (50 SX) * The steering head bearing should be checked regularly for play. To check, support the motorcycle frame and lift the front wheel off the ground. Now try to move the fork back and forth –...
The telescopic fork must be serviced at least once a year. To service the fork, proceed as follows: Prop up the motorcycle under the frame to take the load off the front wheel. Disassemble the front wheel, remove screw  from the brake caliper and unscrew holding clamp.
MAINTENANCE WORK ON CHASSIS AND ENGINE min. 1 mm Checking the brake fluid level / refilling * The brake fluid reservoir is combined with the hand brake cylinder on the handlebar. To check the brake fluid level, press the brake pistons back into the basic position.
» MAINTENANCE WORK ON CHASSIS AND ENGINE Changing the basic position of the foot brake lever (50 SX Junior) The basic position of the foot brake lever can be changed by unscrewing screw  and then turning the retainer .
1 mm Refilling the rear brake fluid reservoir (50 SX) * Remove the screws  and take off the cover  and diaphragm .The brake pistons must be pushed back to their basic position. Fill DOT 5.1 brake fluid (e.g.
– If you don’t happen to have a torque wrench at hand, make sure you have the tightening torque corrected by a KTM dealer as soon as possible. A loose axle may lead to an unstable driving behavior of your motorcycle.
Check spoke tension, especially on a new motorcycle, at regular intervals. If necessary, have the spokes retightened and the wheel centered by a KTM dealer. – Spokes can tear if you continue to ride with them loose. This may lead to an unstable handling of your motorcycle.
Mount the silencer and check the exhaust system for tightness. Note: Glass fiber yarn packages are offered by your licensed KTM dealer. The exhaust system becomes very hot while the motorcycle is running. to avoid burns do not start work on the exhaust system until it has properly cooled down.
To adjust, loosen the counter nut  and turn the adjusting screw accord- ingly. Finally tighten counter nut and slide the protective cover back on. Adjusting the idle speed Dell’Orto PHVA 14 DS (50 SX Junior) * The idle speed can be adjusted with screw .
MAINTENANCE WORK ON CHASSIS AND ENGINE Checking the gear oil level To check the gear oil level, first remove the plug . With the motorcycle parked in an upright position, a small quantity of oil should flow out of the indicator opening .
In both cases, the engine will not seem to have enough power. Check the clutch engagement speed every 20 hours and correct if necessary or have it corrected by an authorized KTM workshop. To tune your clutch, lay the bike on the left side. To prevent oil from leaking from the transmission vent hose, run the hose upwards and fasten.
» MAINTENANCE WORK ON CHASSIS AND ENGINE CORRECTING CLUTCH WEAR: Check the clutch shoes for wear. If the surface is only slightly worn you can remount them again. NOTE: The centrifugal clutch has an outer diameter of approx. 82.5 mm when new.
Engine overheating Insufficient liquid in cooling system Radiator fins clogged Frothing in cooling system The motorcycle is being driven too slowly, the clutch keeps slipping, causing heat to develop Pinched or kinked water hoses Incorrect ignition timing because of loose stator...
– Before cleaning with water, plug the exhaust pipe to prevent water ingress. – After the motorcycle has been rinsed with a soft water jet, it should be dried by air pressure and a cloth. Then take a short drive until the engine has reached its operating temperature, and also operate the brakes.
Allan head screw-Stator Oil plug Oil drain plug Other engine screws » 50 SX JUNIOR single cylinder 2-stroke engine, with reed valve inlet 49.0 cc 39.5 / 40 mm SUPER fuel, research octane no 95, mixed with 2-stroke oil 1 : 60 when using high grade 2-stroke oil (Motorex 2T Cross Power) When in doubt,...
Air chamber length STANDARD ADJUSTMENT - SHOCK ABSORBER Rebound adjuster Spring Spring preload » 50 SX JUNIOR single downtube, split-cradle Marzocchi Ø = 32 mm 140/205 mm (5.5/8 in) Central shock absorber WP Disk brake Ø 160 mm (6.4 in) Drum brake Ø...