KTM 50 SX MINI, 50 SX User Manual
OWNER'S MANUAL 2010
50 SX
50 SX Mini
Art. no. 3211477en
DEAR KTM CUSTOMER 1
DEARKTM CUSTOMER
Congratulations on your decision to purchase a KTM motorcycle. You are now the owner of a state-of-the-art sports motorcycle that will
give you and your child enormous pleasure if you service and maintain it accordingly.
We wish you great pleasure riding the vehicle!
Enter the serial numbers of your vehicle below.
Chassis number ( p. 9) Dealer's stamp
Engine number ( p. 9)
The owner's manual corresponded to the latest state of this series at the time of printing. Slight deviations resulting from continuing
development and design can, however, not be completely excluded.
All specifications are non-binding. KTM Sportmotorcycle AG specifically reserves the right to modify or delete technical specifications, prices, colors, forms, materials, services, designs, equipment, etc., without prior notice and without specifying reasons, to adapt
these to local conditions, as well as to stop production of a particular model without prior notice. KTM accepts no liability for delivery options, deviations from illustrations and descriptions, as well as for printing and other errors. The models portrayed partly contain
special equipment that does not belong to the regular scope of delivery.
© 2009 by KTM-Sportmotorcycle AG, Mattighofen Austria
All rights reserved
Reproduction, even in part, is permitted only with the express written permission of the copyright owner.
ISO 9001(12 100 6061)
According to the international quality management standard ISO 9001, KTM uses quality assurance processes that lead
to the maximum possible quality of the products.
Issued by: TÜV Management Service
KTM-Sportmotorcycle AG
5230 Mattighofen, Austria
TABLE OF CONTENTS 2
TABLEOF CONTENTS
MEANS OF REPRESENTATION ............................................ 4
IMPORTANT INFORMATION ................................................ 5
VIEW OF VEHICLE............................................................... 7
View of the vehicle from the left front (example) ................. 7
View of the vehicle from the right rear (example) ................ 8
LOCATION OF SERIAL NUMBERS ........................................ 9
Chassis number............................................................... 9
Engine number................................................................ 9
Shock absorber part number ............................................. 9
CONTROLS....................................................................... 10
Throttle grip.................................................................. 10
Hand brake lever ........................................................... 10
Short circuit button ....................................................... 10
Fuel tap........................................................................ 10
Opening filler cap.......................................................... 10
Closing filler cap ........................................................... 11
Opening oil tank cap (50 SX Mini) .................................. 11
Closing oil tank cap (50 SX Mini).................................... 11
Choke (50 SX)............................................................... 11
Choke (50 SX Mini) ....................................................... 11
Kickstarter.................................................................... 12
Foot brake pedal ........................................................... 12
Plug-in stand ................................................................ 12
GENERAL TIPS AND HINTS ON PUTTING INTO
OPERATION...................................................................... 13
Advice on first use ......................................................... 13
Running in the engine.................................................... 14
RIDING INSTRUCTIONS .................................................... 15
Checks before putting into operation ............................... 15
Starting ........................................................................ 15
Starting up ................................................................... 16
Shifting, riding.............................................................. 16
Braking ........................................................................ 16
Stopping, parking .......................................................... 16
Refueling...................................................................... 17
Filling up with oil (50 SX Mini) ....................................... 17
SERVICE SCHEDULE......................................................... 18
Important maintenance work that must be done in an
authorized KTM workshop .............................................. 18
Important maintenance work that must be done in an
authorized KTM workshop (as additional order)................. 18
Performance of urgent inspection and care work by the
supervisory individual. ................................................... 19
MAINTENANCE WORK ON CHASSIS AND ENGINE .............. 20
Jacking up the motorcycle .............................................. 20
Removing the motorcycle from the work stand.................. 20
Adjusting the rebound damping of the shock absorber....... 20
Measuring rear wheel sag unloaded ................................. 20
Checking the static sag of the shock absorber .................. 21
Checking the riding sag of the shock absorber .................. 21
Adjusting the spring preload of the shock absorber x ...... 21
Adjusting the riding sag x............................................. 22
Removing the shock absorber x..................................... 22
Installing shock absorber x........................................... 23
Vehicle level ................................................................. 23
Adjusting the fork overhang x ....................................... 23
Adjusting seat height x ................................................ 24
Cleaning dust boots of fork legs ...................................... 24
Checking play of steering head bearing............................ 25
Adjusting play of steering head bearing x....................... 25
Removing the fork legs x.............................................. 26
Installing the fork legs x............................................... 27
Removing the lower triple clamp x ................................ 28
Installing the lower triple clamp x................................. 29
Greasing the steering head bearing x............................. 30
Dismounting the front fender .......................................... 30
Installing the front fender............................................... 31
Dismounting the start number plate ................................ 31
Installing the start number plate ..................................... 31
Handlebar position ........................................................ 32
Adjusting handlebar position x...................................... 32
Checking the play in the throttle cable............................. 32
Adjusting the play in the throttle cable x ....................... 33
Checking chain dirt ....................................................... 33
Cleaning the chain......................................................... 33
Checking the chain tension ............................................ 34
Checking the chain tension - installing rear wheel............. 34
Checking rear sprocket / engine sprocket for wear ............. 34
Adjusting chain tension.................................................. 35
Adjusting chain tension - after checking .......................... 35
Adjusting chain tension - installing rear wheel.................. 36
Adjusting the chain guide x.......................................... 36
Checking brake discs ..................................................... 36
Checking play of handbrake lever .................................... 37
Adjusting play of handbrake lever.................................... 37
Adjusting basic position of handbrake lever...................... 37
Checking the front brake fluid level ................................. 37
Adding front brake fluid x ............................................ 38
Checking the front brake linings...................................... 39
Removing front brake linings x ..................................... 39
Installing the front brake linings x................................. 39
Changing the front brake linings x................................. 40
Checking the free travel of the foot brake lever ................. 41
Adjusting basic position of foot brake pedal x ................ 41
Checking rear brake fluid level ........................................ 42
Adding rear brake fluid x.............................................. 42
Checking the rear brake linings ....................................... 43
Removing rear brake linings x....................................... 43
Installing the rear brake linings x.................................. 44
Changing the rear brake linings x.................................. 44
Removing front wheel x................................................ 45
Installing the front wheel x........................................... 45
Removing rear wheel x................................................. 46
Installing the rear wheel x ............................................ 46
Checking the tire condition............................................. 47
Checking tire air pressure ............................................... 47
Checking spoke tension.................................................. 47
Removing the seat ......................................................... 48
Mounting the seat ......................................................... 48
Cooling system .............................................................. 48
Checking the antifreeze and coolant level ........................ 49
Checking the coolant level.............................................. 49
Draining the coolant x.................................................. 50
Refilling coolant x ....................................................... 50
Removing main silencer ................................................. 51
Installing the main silencer ............................................ 51
Glass fiber yarn filling of main silencer ............................ 52
Removing the glass fiber yarn filling of the main
silencer x ................................................................... 52
Installing the glass fiber yarn filling of the main
silencer x ................................................................... 52
Removing the air filter x............................................... 52
Installing the air filter x ............................................... 53
TABLE OF CONTENTS 3
Cleaning air filter x...................................................... 53
Carburetor - idle (50 SX) ................................................ 53
Carburetor - idle (50 SX Mini)......................................... 54
Carburetor - adjusting idle speed x (50 SX).................... 54
Carburetor - adjusting idle speed x (50 SX Mini) ............ 55
Checking oil level (50 SX Mini)....................................... 55
Bleeding oil pump x (50 SX Mini) ................................. 56
Checking gear oil level ................................................... 57
Changing the gear oil x ................................................ 57
Draining the gear oil x ................................................. 58
Filling up with gear oil x .............................................. 58
Adding gear oil x ......................................................... 58
Checking clutch engagement speed x............................ 59
Adjust the clutch engagement speed x .......................... 59
Removing centrifugal clutch x ...................................... 60
Fitting centrifugal force clutch x................................... 61
Checking/measuring clutch x........................................ 61
Dismantling centrifugal clutch x ................................... 62
Assembling centrifugal clutch x.................................... 62
TROUBLESHOOTING......................................................... 64
CLEANING........................................................................ 66
Cleaning motorcycle ...................................................... 66
STORAGE ......................................................................... 67
Storage......................................................................... 67
Putting into operation after storage ................................. 67
TECHNICAL DATA - ENGINE .............................................. 68
Capacity - gear oil.......................................................... 68
Capacity - coolant.......................................................... 68
TECHNICAL DATA - ENGINE TIGHTENING TORQUES .......... 69
TECHNICAL DATA - CARBURETOR..................................... 70
50 SX........................................................................... 70
50 SX Mini ................................................................... 70
TECHNICAL DATA - CHASSIS ............................................ 71
Tires ............................................................................ 71
Capacity - fuel............................................................... 72
TECHNICAL DATA - FORK.................................................. 73
50 SX........................................................................... 73
50 SX Mini ................................................................... 73
TECHNICAL DATA - SHOCK ABSORBER ............................. 74
50 SX........................................................................... 74
50 SX Mini ................................................................... 74
TECHNICAL DATA - CHASSIS TIGHTENING TORQUES ........ 75
OPERATING SUBSTANCES................................................ 76
AUXILIARY SUBSTANCES.................................................. 78
STANDARDS..................................................................... 80
INDEX .............................................................................. 81
MEANS OF REPRESENTATION 4
Symbols used
The symbols used are explained in the following.
Indicates an expected reaction (e.g. of a work step or a function).
Indicates an unexpected reaction (e.g. of a work step or a function).
All work marked with this symbol requires specialist knowledge and technical understanding. In the interest of
your own safety, have these jobs done in an authorized KTM workshop! There, your motorcycle will be serviced
optimally by specially trained experts using the specialist tools required.
Identifies a page reference (more information is provided on the specified page).
Formats used
The typographical and other formats used are explained in the following.
Proper name Identifies a proper name.
®
Name
Brand™ Identifies a brand in merchandise traffic.
Identifies a protected name.
IMPORTANT INFORMATION 5
Use definition
KTM sport motorcycles are designed and built to withstand the normal stresses and strains of competitive use. The motorcycles comply with currently valid regulations and categories of the top international motorsport organizations.
Info
The motorcycle must be used only in closed off areas remote from public road traffic.
Maintenance
A prerequisite for perfect operation and prevention of wear is that the engine and chassis maintenance and adjustment work described
in the owner's manual are properly carried out. Poor adjustment and tuning of the engine and chassis can lead to damage and breakage of components.
Using the motorcycle in difficult conditions such as on sand or very muddy or wet terrain can lead to above-average wear of components such as the transmission train or the brakes. For this reason, it may be necessary to service or replace worn parts before the
limit specified in the service schedule is reached.
Pay careful attention to the prescribed running-in period, inspection and maintenance intervals. If you observe these exactly, you will
ensure a much longer service life for your motorcycle.
Warranty
The work prescribed in the service schedule must be carried out in an authorized KTM workshop only and confirmed in the customer's
service record, since otherwise no warranty claims will be honored. No warranty claims can be honored for damage resulting from
manipulations and/or alterations to the vehicle.
Fuel, oils, etc.
You should use the fuels, oils and greases according to specifications as listed in the owner's manual.
Spare parts, accessories
For your own safety, only use spare parts and accessory products that have been approved and/or recommended by KTM and have
them installed by an authorized KTM workshop. KTM accepts no liability for other products and any resulting damage or loss.
Certain spare parts and accessories are specified in parentheses in the descriptions. Your KTM dealer will be glad to advise you.
The current KTM PowerParts for your vehicle can be found on the KTM website.
International KTM Website: http://www.ktm.com
Work rules
Special tools are needed for certain tasks. They are not included with the vehicle but can be ordered under the number in parentheses. Ex.: bearing puller (15112017000)
During assembly, non-reusable parts (e.g. self-locking screws and nuts, seals, seal rings, O-rings, pins, lock washers) must be replaced
by new parts.
If a thread locker is used for the screw connections (e.g. Loctite®), follow the specific manufacturer instructions regarding its use.
Parts that are to be reused after disassembly must be cleaned and checked for damage and wear. Change damaged or worn parts.
After repair and maintenance, ensure that the vehicle is roadworthy.
Transport
Note
Danger of damage The parked vehicle can roll away or fall over.
– Always place the vehicle on a firm and even surface.
Note
Fire hazard Some vehicle components get very hot when the machine is driven.
– Do not place the vehicle where there are flammable or explosive substances. Do not place objects over the vehicle while it is still
warm from being run. Always let the vehicle cool first.
– Switch off the engine.
– Use straps or other suitable devices to secure the motorcycle against accidents or falling over.
IMPORTANT INFORMATION 6
Environment
Motorcycling is a wonderful sport and we naturally hope that you and your child will be able to enjoy it to the fullest. However, it is a
potential problem for the environment and can lead to conflicts with other persons. But if you use your motorcycle responsibly, you
can ensure that such problems and conflicts do not have to occur. To protect the future of motorcycle sport, make sure that your child
uses the motorcycle legally, display environmental consciousness, and respect the rights of others.
notes/warnings
Be sure to pay attention to the notes and warnings given here.
Info
Various notes and warning stickers are attached to the vehicle. Do not remove any notes and warning stickers. If they are missing, you or others may not recognize sources of danger and may therefore be injured.
Grades of risks
Danger
Indicates immediate danger that will invariably lead to severe or even fatal injury if the appropriate measures are not taken.
Warning
Indicates immediate danger that may lead to severe or even fatal injury if the appropriate measures are not taken.
Note
Identifies a danger that will lead to considerable machine and material damage if the appropriate measures are not taken.
Warning
Indicates immediate danger that will invariably lead to environmental damage if the appropriate measures are not taken.
Owner's manual
– Carefully read this owner's manual in its entirety together with your child before letting your child ride the motorcycle for the first
time. It contains a lot of information and tips to help you and your child operate and handle the motorcycle. Only then will you
find out how to customize the motorcycle ideally for your child's use and how to protect your child from injury. The owner's manual
also contains important information on servicing the motorcycle.
– The owner's manual is an important component of the motorcycle and should be handed over to the new owner if the vehicle is
sold.
VIEW OF VEHICLE 7
3.1View of the vehicle from the left front (example)
1 Hand brake lever
2 Filler cap
3 Fuel tap
4 Quick release for seat lock
5 Shock absorber compression adjustment
6 Chain guide
7 Plug-in stand
B00068-10
VIEW OF VEHICLE 8
3.2View of the vehicle from the right rear (example)
1 Short circuit button
2 Chassis number
3 Throttle grip
4 Level viewer for brake fluid, rear
5 Foot brake pedal
6 Kickstarter
B00069-10
LOCATION OF SERIAL NUMBERS 9
4.1Chassis number
The chassis number is stamped on right of the steering head.
700460-01
4.2Engine number
The engine number is stamped on the left side of the engine under the engine
sprocket.
4.3Shock absorber part number
700461-01
The shock absorber part number is stamped on the top of the shock absorber above
the adjusting ring towards the rear.
700469-01
CONTROLS 10
5.1Throttle grip
Throttle grip is fitted on the right side of the handlebar.
700470-01
5.2Hand 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.
5.3Short circuit button
5.4Fuel tap
700471-01
Short circuit button is fitted on the left side of the handlebar.
Possible states
• Short circuit button in basic position – In this position, the ignition circuit is
closed, and the engine can be started.
• Short circuit button pressed – In this position, the ignition circuit is interrupted,
a running engine stops, and a non-running engine will not start.
700462-01
Fuel tap is on the left of the fuel tank.
Possible states
• Fuel tap is closed – The knurled screw is turned all the way clockwise. Fuel cannot
flow out of the fuel tank.
• Fuel tap is open – The knurled screw is turned all the way counterclockwise. Fuel
can flow out of the fuel tank.
5.5Opening filler cap
700463-01
– Turn the tank cap counterclockwise and pull it up.
700465-10
CONTROLS 11
5.6Closing filler cap
– Put the tank cap on and turn it clockwise.
Info
Run the fuel tank breather hose without kinks.
700465-11
5.7Opening oil tank cap (50 SX Mini)
– Turn the oil tank cap counterclockwise and pull it up.
700517-01
5.8Closing oil tank cap (50 SX Mini)
700517-10
5.9Choke (50 SX)
700464-01
– Put the oil tank cap on and turn it clockwise.
Info
Run the oil tank breather hose without kinks.
The choke knob is fitted on the left of the carburetor.
Activating the choke function frees an opening through which the engine can draw
extra fuel. This gives a richer fuel-air mixture, which is needed for a cold start.
Info
If the engine is warm, the choke function must be deactivated.
Possible states
• Choke function activated – Choke knob is in upper position. The O-ring is visible.
• Choke function deactivated – Choke knob is in lower position. No O-ring is visible.
5.10Choke (50 SX Mini)
700519-01
The choke lever is fitted on the right of the carburetor.
Activating the choke function frees an opening through which the engine can draw
extra fuel. This gives a richer fuel-air mixture, which is needed for a cold start.
Info
If the engine is warm, the choke function must be deactivated.
Possible states
• Choke function activated – The choke lever is pushed up all the way.
• Choke function deactivated – The choke lever is pushed down all the way.
CONTROLS 12
5.11Kickstarter
The kickstarter is fitted on the right of the engine.
The kickstarter can be swiveled.
Info
Before riding, swing the kickstarter inwards towards the engine.
700472-01
5.12Foot brake pedal
Foot brake pedal is located in front of the right footrest.
The foot brake pedal is used to activate the rear brake.
5.13Plug-in stand
700473-01
700474-01
Note
Danger of damage The parked vehicle can roll away or fall over.
– Always place the vehicle on a firm and even surface.
To park the motorcycle, insert the plug-in stand in the support for the plug-in stand
on the left of the vehicle.
Info
Remove the plug-in stand before riding.
GENERAL TIPS AND HINTS ON PUTTING INTO OPERATION 13
6.1Advice on first use
Warning
Danger of accidents Physical and mental readiness of a child.
– Your child must be able to ride a bicycle and must be able to erect the vehicle independently after a fall. In addition, your
child must understand the regulations and instructions from you or from other guardians. Do not ask too much of your
child; participation in a race should not be considered until your child's stamina, riding techniques and motivation are at
the necessary levels. Children often underestimate or fail to recognize dangerous situations; make it clear to your child that
it should not, under any circumstances, operate the vehicle without supervision and that your child may only drive at
speeds that are commensurate with the child's riding abilities and the road conditions.
– Only let your child ride on the vehicle if it is physically and mentally ready to operate the vehicle.
Warning
Risk of injury Missing or poor protective clothing present an increased safety risk.
– Wear protective clothing (helmet, boots, gloves, pants and jacket with protectors) every time you ride the motorcycle. You
and your child should always used protective clothing that is in good condition and meets the legal requirements. When
you ride a motorcycle, set an example for your child and wear suitable protective clothing.
Warning
Danger of crashing Impairment of handling characteristic due to different tire tread patterns on front and rear wheels.
– The front and rear wheels must be fitted with tires with similar tread patterns to prevent loss of control over the vehicle.
Warning
Danger of accidents Critical riding behavior due to inappropriate riding.
– Ensure that your child adjusts the riding speed to the road conditions and to his or her riding abilities.
Warning
Danger of accidents Accident risk caused by presence of a passenger.
– Your vehicle is not designed to carry passengers. Do not ride with a passenger.
Warning
Danger of accidents Brake system failure.
– If the foot brake pedal is not released, the brake linings drag permanently. The rear brake can fail due to overheating.
Ensure that your child raises his or her foot from the foot brake pedal when the child does not want to brake.
Warning
Danger of accidents Destruction of chassis components.
– Do not exceed the maximum allowable rider weight.
Warning
Risk of misappropriation Usage by unauthorized persons.
– Never leave the vehicle while the engine is running. Secure the vehicle against use by unauthorized persons.
Info
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 record at vehicle handover.
– Carefully read the entire owner's manual together with your child before going for the first ride.
Info
Pay special attention to the safety warnings and injury risks.
Explain to your child the techniques of riding and falling, e.g. how shifting weight can influence handling characteristics.
– Familiarize your child with the controls.
– Adjust the basic position of the handbrake lever. ( p. 37)
–
Adjust the basic position of the foot brake pedal. x ( p. 41)
– Before using the vehicle for the first time, ensure that the basic settings of the chassis are suitable for the weight of your child.
– Accustom your child to the handling of the motorcycle on suitable terrain, preferably on a large open meadow.
GENERAL TIPS AND HINTS ON PUTTING INTO OPERATION 14
Info
To give your child a feel for the brake, you should push your child at first. Do not start the engine until your child can is
able to apply the necessary brake pressure.
At the start, let your child ride to another person who can help him or her stop and turn.
– Erect obstacles for your child to navigate around to accustom your child to handling the vehicle.
– Your child should also try to ride as slowly as possible and in a standing position to get a better feeling for the vehicle.
– Do not let your child try any off-road rides that would exceed the ability and experience of your child.
– Your child should hold the handlebar firmly with both hands and keep his or her feet on the footrests when riding.
– Do not exceed the maximum allowable rider weight.
Guideline
Maximum rider weight < 35 kg (< 77 lb.)
Maximum rider size < 130 cm (< 51.2 in)
– Check the spoke tension. ( p. 47)
Info
The spoke tension must be checked after riding the motorcycle for half an hour.
– Run the engine in. ( p. 14)
6.2Running in the engine
– During the running-in phase, do not exceed the specified engine performance.
Guideline
Maximum engine performance
During the first 3 service hours < 70 %
During the first 5 service hours < 100 %
– Avoid fully opening the throttle!
RIDING INSTRUCTIONS 15
7.1Checks before putting into operation
Info
Make sure that the motorcycle is in a perfect technical condition before use.
Info
In the interests of riding safety, make it your own and your child's habit to perform a general check before going for a ride.
Insist that your child perform the general checks himself or herself.
– Check the gear oil level. ( p. 57)
(50 SX Mini)
– Check the oil level. ( p. 55)
– Check the chain tension. ( p. 34)
– Check the chain dirt accumulation. ( p. 33)
– Check the tire condition. ( p. 47)
– Check the tire air pressure. ( p. 47)
– Check the front brake fluid level. ( p. 37)
– Check the rear brake fluid level. ( p. 42)
– Check the front brake linings. ( p. 39)
– Check the rear brake linings. ( p. 43)
– Check the function of the brake system.
– Check the coolant level. ( p. 49)
– Check the settings of all controls and ensure that they can be operated smoothly.
– Check the functioning of the electrical equipment.
7.2Starting
Danger
Danger of poisoning Exhaust gases are poisonous and can result in unconsciousness and/or death.
– When running the engine, always make sure there is sufficient ventilation, and do not start or run the engine in a closed
space without an effective exhaust extraction system.
Note
Engine failure High engine speeds in cold engines have a negative effect on the service life of the engine.
– Always warm up the engine at low engine speeds.
Info
If the motorcycle is unwilling to start, the cause can be old fuel in the float chamber. The flammable elements of the fuel
evaporate after a long time of standing.
If the float chamber is filled with fresh fuel, the engine starts immediately.
– Turn the knurled screw on the fuel tap all the way counterclockwise.
Fuel can flow from the fuel tank to the carburetor.
– Remove the motorcycle from the stand.
The engine is cold
(50 SX)
– Pull the choke knob fully out and turn it by max. ¼ turn.
(50 SX Mini)
– Push the choke lever up all the way.
– Forcefully step on the kickstarter, pushing it all the way forward.
Info
Do not open the throttle.
RIDING INSTRUCTIONS 16
7.3Starting up
Info
The plug-in stand must be removed before you start your journey.
– Open the throttle carefully.
7.4Shifting, riding
Info
If you hear unusual noises while riding, stop immediately, switch off the engine and contact an authorized KTM workshop.
– If the choke function was activated, deactivate it after the engine has warmed up.
– When you reach maximum speed after fully opening the throttle, turn back the throttle to about ¾ of its range. The speed hardly
drops, but the fuel consumption falls considerably.
– Your child should always open the throttle only as much as the engine can handle – abruptly opening the throttle increases fuel
consumption.
– Your child should switch off the engine if he or she expects to be standing for a long time.
Guideline
≥ 2 min
7.5Braking
Warning
Danger of accidents If you brake too hard, the wheels can lock.
– Adapt your braking to the traffic situation and the road conditions.
Warning
Danger of accidents Reduced braking efficiency caused by spongy pressure point of front or rear brake.
– Check the brake system and do not continue riding. (Your authorized KTM workshop will be glad to help.)
Warning
Danger of accidents Reduced braking efficiency due to wet or dirty brakes.
– Clean or dry dirty or wet brakes by riding and braking gently.
– On sandy, wet or slippery surfaces, use the rear brake.
– Braking should always be completed before you go into a bend.
7.6Stopping, parking
Warning
Risk of misappropriation Usage by unauthorized persons.
– Never leave the vehicle while the engine is running. Secure the vehicle against use by unauthorized persons.
Warning
Danger of burns Some vehicle components get very hot when the machine is driven.
– Do not touch hot components such as exhaust system, radiator, engine, shock absorber and brakes. Allow these compo-
nents to cool down before starting work on them.
Note
Danger of damage The parked vehicle can roll away or fall over.
– Always place the vehicle on a firm and even surface.
Note
Fire hazard Some vehicle components get very hot when the machine is driven.
– Do not place the vehicle where there are flammable or explosive substances. Do not place objects over the vehicle while it is still
warm from being run. Always let the vehicle cool first.
RIDING INSTRUCTIONS 17
00
0
AA
Note
Material damage Damage and destruction of components due to excessive load.
– The plug-in stand is designed for the weight of the motorcycle only. You or your child should not sit on the motorcycle when it is
standing on the plug-in stand. The plug-in stand and/or the frame could be damaged and the motorcycle could fall over.
– Brake the motorcycle.
– Press and hold the short circuit button while the engine is idling until the engine stops.
– Turn the knurled screw on the fuel tap all the way clockwise.
– Park the motorcycle on firm ground.
7.7Refueling
Danger
Fire hazard Fuel can easily catch fire.
– Never fill up the vehicle near open flames or burning cigarettes, and always switch off the engine first. Be careful that no
fuel is spilt, especially on hot vehicle components. Clean up spilt fuel immediately.
– Fuel in the fuel tank expands when warm and can escape if the tank is overfilled. See specifications on filling up with fuel.
Warning
Danger of poisoning Fuel is poisonous and a health hazard.
– Avoid contact of the fuel with skin, eyes and clothing. Do not inhale fuel vapors. If fuel gets into your eyes, rinse imme-
diately with water and contact a doctor. Wash affected skin areas immediately with soap and water. If fuel is swallowed,
contact a doctor immediately. Change clothing that has come into contact with fuel.
Warning
Environmental hazard Improper handling of fuel is a danger to the environment.
– Do not allow fuel to get into the ground water, the ground, or the sewage system.
– Switch off the engine.
– Open the filler cap. ( p. 10)
– Fill the fuel tank with fuel up to measurement .
Guideline
Measurement of 35 mm (1.38 in)
400214-10
7.8Filling up with oil (50 SX Mini)
Fuel tank
capacity, approx.
(50 SX Mini)
Fuel tank
capacity, approx.
(50 SX)
– Close the filler cap. ( p. 11)
2.0 l (2.1 qt.) Super unleaded (ROZ 95 / RON 95 /
2.3 l (2.4 qt.) Super unleaded gasoline, mixed with
Warning
Engine failure If the vehicle is run without 2-stroke oil in the tank, the result is engine failure.
– The oil tank must always be filled up to the MIN mark.
PON 91) ( p. 77)
2-stroke engine oil (1:60) ( p. 77)
700518-01
– Switch off the engine.
– Open the oil tank cap. ( p. 11)
– Fill the oil tank at least up to the MIN mark .
Guideline
MIN mark Sufficient for a single tank filling
Oil tank contents
ca.
– Close the oil tank cap. ( p. 11)
0.2 l (0.2 qt.) 2-stroke engine oil ( p. 76)
SERVICE SCHEDULE 18
8.1Important maintenance work that must be done in an authorized KTM workshop
S20A S40A
engine
Change the gear oil. x ( p. 57)
Check spark plug and replace if required. x
Clean spark plug connectors and check for tightness. x
• •
• •
Check engine mounting screws for tightness. • •
Check the clutch engagement speed. x ( p. 59)
• •
carburetor Check intake flange and carburetor connection boot for cracks and leakage. •
Check idle. • •
Check vent hoses for damage and routing without sharp bends. •
Attachments Check the cooling system for leakage. •
Check the antifreeze and coolant level. ( p. 49) •
Check exhaust system for leakage and looseness. • •
Check throttle cables for damage, smooth operation and routing without sharp bends. •
Clean the air filter. x ( p. 53)
• •
Brakes Check the front brake linings. ( p. 39) •
Check the rear brake linings. ( p. 43) •
Check the brake discs. ( p. 36) •
Check the front brake fluid level. ( p. 37) • •
Check the rear brake fluid level. ( p. 42) • •
Check brake lines for damage and leakage. •
Check the play of the handbrake lever. ( p. 37) • •
Check the free travel of the foot brake lever. ( p. 41) • •
Check the function of the brake system. • •
Check screws and guide bolts of brake system for tightness. • •
Chassis
Check shock absorber and fork for leakage and functioning. x
• •
Clean dust boots of fork legs. ( p. 24) • •
Check swingarm bearing. •
Check play of steering head bearing. ( p. 25) •
Check all screws to see if they are tight. • •
Wheels Check the spoke tension. ( p. 47) • •
Check rim run-out. • •
Check the tire condition. ( p. 47) • •
Check the tire air pressure. ( p. 47) • •
Check the chain wear. • •
Check the chain tension. ( p. 34) • •
Clean the chain. ( p. 33) • •
Check wheel bearing for play. • •
Clean and grease adjusting screws of chain adjuster. • •
•
S20A: every 20 service hours
S40A: every 40 service hours
8.2Important maintenance work that must be done in an authorized KTM workshop (as additional order)
S20A S40A S80A J1A
Check/set the carburetor components. (50 SX Mini) x
Check/set the carburetor components. (50 SX) x
Check the reed valve housing, diaphragm and intake flange. x
Check/measure the clutch. x ( p. 61)
Checking wear of clutch drum. x
Determine the piston/cylinder mounting clearance. x
Check the seating of the piston pin. x
• • •
• • •
• • •
• • •
• • •
•
•
SERVICE SCHEDULE 19
S20A S40A S80A J1A
Check main bearing of the crankshaft. x
Check radial clearance of conrod bearing. x
Change crankshafts and conrod bearings. x
Service the fork. x
Service the shock absorber. x
Clean and lubricate swingarm bearing. x
Grease the steering head bearing. x ( p. 30)
Change the glass fiber yarn filling of the main silencer. x
Change the front brake fluid. x
Change the rear brake fluid. x
S20A: every 20 service hours
S40A: every 40 service hours
S80A: every 80 service hours
J1A: annually
8.3Performance of urgent inspection and care work by the supervisory individual.
Check the gear oil level. ( p. 57) •
Check the front brake fluid level. ( p. 37) •
Check the rear brake fluid level. ( p. 42) •
Check the front brake linings. ( p. 39) •
Check the rear brake linings. ( p. 43) •
Check and adjust throttle cables. •
Bleed fork legs. •
Clean dust boots of fork legs. ( p. 24) •
Clean the chain. ( p. 33) •
Check the chain tension. ( p. 34) •
Check the chain wear. •
Check rear sprocket / engine sprocket for wear. ( p. 34) •
Clean the air filter. x ( p. 53)
Check the tire air pressure. ( p. 47) •
Check the tire condition. ( p. 47) •
Check the coolant level. ( p. 49) •
Check all controls for smooth operation. •
Check braking. •
Check all screws, nuts and hose clamps regularly for tightness. •
• • •
• • •
• •
• •
•
•
•
• • •
•
•
NB1A
•
NB1A: Depending on conditions of use according to requirements.
MAINTENANCE WORK ON CHASSIS AND ENGINE 20
00AA
9.1Jacking up the motorcycle
Note
Danger of damage The parked vehicle can roll away or fall over.
– Always place the vehicle on a firm and even surface.
– Jack up the motorcycle underneath the engine.
Work stand (54829055000)
– Secure the motorcycle against falling over.
700475-01
9.2Removing the motorcycle from the work stand
Note
Danger of damage The parked vehicle can roll away or fall over.
– Always place the vehicle on a firm and even surface.
– Remove the motorcycle from the work stand.
– Remove the work stand.
9.3Adjusting the rebound damping of the shock absorber
Danger
Danger of accidents Disassembly of pressurized parts can lead to injury.
– The shock absorber is filled with high density nitrogen. Adhere to the description provided. (Your authorized KTM workshop
will be glad to help.)
– Turn adjusting screw clockwise to the last perceptible click.
– Turn back counterclockwise by the number of clicks corresponding to the shock
absorber type.
Guideline
Rebound damping (50 SX)
Standard 10 clicks
Rebound damping (50 SX Mini)
Standard 12 clicks
700476-01
Info
Turn clockwise to increase damping, turn counterclockwise to reduce suspension damping.
9.4Measuring rear wheel sag unloaded
– Jack up the motorcycle. ( p. 20)
– Measure the distance – as vertical as possible – between the rear axle and a fixed
point, for example, a mark on the side cover.
– Make a note of the value as measurement .
– Remove the motorcycle from the work stand. ( p. 20)
400220-10
MAINTENANCE WORK ON CHASSIS AND ENGINE 21
000BB
0
0
AA
CC
0
0
AA
9.5Checking the static sag of the shock absorber
– Measure distance of rear wheel unloaded. ( p. 20)
– Ask someone to help you by holding the motorcycle upright.
– Measure the distance between the rear axle and the fixed point again.
– Make a note of the value as measurement .
Info
The static sag is the difference between measurements and .
– Check the static sag.
Static sag (50 SX) 20 mm (0.79 in)
Static sag (50 SX Mini) 15 mm (0.59 in)
» If the static sag is less or more than the specified value:
–
Adjust the spring preload of the shock absorber. x ( p. 21)
400221-10
9.6Checking the riding sag of the shock absorber
– Measure distance of rear wheel unloaded. ( p. 20)
– Hold the motorcycle in a vertical position and seat the rider, wearing a full set of
protective clothing, on the motorcycle in the normal sitting position (feet on the
footrests). The rider should bounce up and down several times so that the rear
wheel suspension can level out.
– Now measure the distance between the rear axle and the fixed point again.
– Make a note of the value as measurement .
Info
The riding sag is the difference between measurements and .
– Check the riding sag.
Riding sag (50 SX) 45… 55 mm (1.77… 2.17 in)
Riding sag (50 SX Mini) 40… 50 mm (1.57… 1.97 in)
» If the riding sag differs from the specified measurement:
–
Adjust the riding sag. x ( p. 22)
400222-10
9.7Adjusting the spring preload of the shock absorber x
Danger
Danger of accidents Disassembly of pressurized parts can lead to injury.
– The shock absorber is filled with high density nitrogen. Adhere to the description provided. (Your authorized KTM workshop
will be glad to help.)
–
Remove shock absorber. x ( p. 22)
– After removing the shock absorber, clean it thoroughly.
MAINTENANCE WORK ON CHASSIS AND ENGINE 22
– Measure the full spring length while it is under tension and note down the value.
– Loosen lock ring .
– Turn adjusting ring until the spring is no longer under tension.
Hook wrench (T106S)
– Measure the overall spring length when not under tension.
– Tighten the spring by turning adjusting ring to measurement.
Guideline
700506-01
Spring preload (50 SX)
Standard 3 mm (0.12 in)
Spring preload (50 SX Mini)
Standard 5 mm (0.2 in)
Info
Measure is the difference between the relaxed spring length and the tensioned spring length.
Depending on the static sag and/or the riding sag, it may be necessary to
increase or decrease the spring preload.
– Tighten lock ring .
–
Install shock absorber. x ( p. 23)
9.8Adjusting the riding sag x
–
Remove shock absorber. x ( p. 22)
– After removing the shock absorber, clean it thoroughly.
– Choose and mount a suitable spring.
Guideline
Spring rate (50 SX)
Weight of rider: < 25 kg (< 55 lb.) 30 N/mm (171 lb/in)
Weight of rider: 25… 35 kg (55… 77 lb.) 35 N/mm (200 lb/in)
Weight of rider: > 40 kg (> 88 lb.) 40 N/mm (228 lb/in)
Spring rate (50 SX Mini)
Weight of rider: < 25 kg (< 55 lb.) 65 N/mm (371 lb/in)
Weight of rider: 25… 35 kg (55… 77 lb.) 75 N/mm (428 lb/in)
Weight of rider: > 35 kg (> 77 lb.) 85 N/mm (485 lb/in)
Info
The spring rate is shown on the outside of the spring.
Smaller weight differences can be compensated by changing the spring preload.
–
Install shock absorber. x ( p. 23)
– Check the static sag of the shock absorber. ( p. 21)
– Check the riding sag of the shock absorber. ( p. 21)
– Adjust the rebound damping of the shock absorber. ( p. 20)
9.9Removing the shock absorber x
700477-01
– Jack up the motorcycle. ( p. 20)
– Remove screw and lower the rear wheel with the swing arm as far as possible
without blocking the rear wheel. Fix the rear wheel in this position.
– Remove screw , push splash protector to the side, and remove the shock
absorber.
MAINTENANCE WORK ON CHASSIS AND ENGINE 23
9.10Installing shock absorber x
– Push the splash protector to the side and position the shock absorber according
to the desired seat height. Mount and tighten screw .
Guideline
Screw, top shock absorber M10 45 Nm
(33.2 lbf ft)
– Mount and tighten screw .
Guideline
301060-10
9.11Vehicle level
Screw, bottom shock absorber M10 45 Nm
(33.2 lbf ft)
– Remove the motorcycle from the work stand. ( p. 20)
Warning
Danger of accidents Modifications to the suspension settings can seriously alter
the vehicle's ride behavior.
– Following modifications, ride slowly at first to get the feel of the new ride
behavior.
700523-10
700521-11
9.12Adjusting the fork overhang x
The vehicle level can be adjusted at the front by means of the clamping of the fork legs
and at the rear by means of the positioning of the shock absorber.
The fork overhang can be individually adjusted to the size of the child. In the lower
position (standard), the fork is completely pushed through. In the higher position ,
the cone is flush with the upper triple clamp.
Fork overhang over the
10… 17 mm (0.39… 0.67 in)
upper triple clamp
The seat height can be individually adjusted to the size of the child. The shock
absorber can be mounted at two different holes in the frame.
Difference between low
25 mm (0.98 in)
(standard) and high seat
position
Warning
Danger of accidents Modifications to the suspension settings can seriously alter the vehicle's ride behavior.
– Following modifications, ride slowly at first to get the feel of the new ride behavior.
– Loosen screws on the lower triple clamp.
– Loosen screw on the upper triple clamp.
Info
Loosen the screws to the point where the fork legs can be moved without
damaging it.
Make the adjustments first on one fork leg and then on the other.
– Adjust the fork overhang with the upper triple clamp.
700524-01
Guideline
10… 17 mm (0.39… 0.67 in)
MAINTENANCE WORK ON CHASSIS AND ENGINE 24
– Tighten screw .
Guideline
Screw, top triple clamp M8 25 Nm
(18.4 lbf ft)
– Fully tighten screws .
Guideline
Screw, bottom triple clamp M6 10 Nm (7.4 lbf ft)
– Repeat the adjustment on the other fork leg.
Info
The setting of the vehicle level via the fork legs must be identical on both
fork legs.
9.13Adjusting seat height x
Warning
Danger of accidents Modifications to the suspension settings can seriously alter the vehicle's ride behavior.
– Following modifications, ride slowly at first to get the feel of the new ride behavior.
–
Remove shock absorber. x ( p. 22)
– Position the shock absorber according to the required seat height.
Guideline
Low seat position (standard)
High seat position
700521-01
9.14Cleaning dust boots of fork legs
700478-11
–
Install shock absorber. x ( p. 23)
– Jack up the motorcycle. ( p. 20)
– Push dust boots of both fork legs upwards.
Info
The dust boots should remove dust and coarse dirt particles from the fork
tubes. Over time, dirt can penetrate behind the dust boots. If this dirt is not
removed, the oil seals behind can start to leak.
Warning
Danger of accidents Reduced braking efficiency due to oil or grease on the
brake discs.
– Always keep the brake discs free of oil and grease, and clean them with
brake cleaner when necessary.
– Clean and oil the dust boots and inner fork tube of both fork legs.
Universal oil spray ( p. 79)
– Press the dust boots back into their normal position.
– Remove excess oil.
– Remove the motorcycle from the work stand. ( p. 20)
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