KTM 50 SX, 50 SX JUNIOR User Manual

50 SX JUNIOR

50 SX

OWNER’S MANUAL 2008

3211222en

ENGLISH

INTRODUCTION

Please insert the serial numbers of the motorcycle below

Chassis number

Engine number

Stamp of dealer

All information contained is without obligation. KTM-Sportmotorcycle AG particularly reserves the right to modify any equipment, technical specifications, prices, colors, shapes, materials, services, service work, constructions, equipment and the like so as to adapt them to local conditions or to cancel any of the above items, all without previous announcement and without giving reasons. KTM may stop manufacturing certain models without previous notice. KTM shall not be held liable for any deviations of availability 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.

Now you own a modern motorcycle that you and your youngster will certainly enjoy, provided that you service and maintain it properly.

In accordance with the international quality management ISO 9001 standard, KTM uses quality assurance processes that lead to the highest possible product quality.

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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 international motorcycle associations.

OWNER’S MANUAL

Please read this manual thoroughly before letting your youngster ride the motorcycle for the first time. This manual contains important information and recommendations that will help you and your youngster to operate and handle the motorcycle properly. In the interest of everybody involved, we urge you to pay particular attention to instructions and information marked as follows:

This manual contains important information on the operation and maintenance of your new KTM motorcycle. It went to press describing your model’s latest state of development. Nevertheless, the descriptions may deviate slightly from the current design as our motorcycles are permanently improved.The Owner's Manual is an integral part of the motorcycle and must be handed over to the new owner when the motorcycle is sold.

SERVICE

Observance of the service, maintenance and tuning instructions for the engine and chassis specified in the Owner's Manual is a prerequisite for faultless operation and the avoidance of premature wear. An improperly tuned chassis can lead to damage and breakage of the chassis components (see chapter on checking the basic chassis setting). The use of the motorcycle under extreme conditions, e.g. on extremely muddy and wet terrain, can lead to higher than average wear on components such as the drive train or the brakes. In this case it may become necessary to service or replace wear parts before the service limit specified in the maintenance schedule has been reached. We expressly point out that work marked with an asterisk (*) in the chapter "Maintenance work on the chassis and engine" must be performed by a KTM workshop. If maintenance work should become necessary during a competition, it must be performed by a trained mechanic. Please strictly observe the prescribed running-in periods and inspection and maintenance intervals. Compliance with these instructions will significantly prolong the life of your motorcycle.

– Ignoring these instructions can be dangerous to life and limb!

– Ignoring these instructions may damage parts of the motorcycle or impair the motorcycle's

traffic safety!

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IMPORTANT INFORMATION

WARRANTY

The service work specified in the "Lubrication and Maintenance Schedule" must be performed by a KTM workshop and recorded in the service manual otherwise claims under the warranty shall become void. No claims can be filed under the warranty for damage or consequential damage caused by manipulations or conversions to the motorcycle.

AUTOMOTIVE FLUIDS

The fuels and lubricants specified in the Owner's Manual or automotive fluids with equivalent specifications must be used in accordance with the maintenance schedule.

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. When special needs arise, please contact a KTM dealer, who will seek the assistance of the KTM importer if necessary.

SAFETY

Parents should keep in mind that the safety of their youngsters always depends on the efforts made by the parents to ensure that the motorcycle is kept in good working order and only used on safe terrains. Nevertheless, driving the motorcycle, like driving any other vehicle, involves a potential risk. Therefore, please make sure that all fundamental precautions are taken. Please also read the „INFORMATION ON SAFE DRIVING FOR PARENTS“ on page 4.

TRANSPORT

When transporting your motorcycle, secure it with elastic straps or other mechaical devices in an upright position. Be sure that the fuel tap is closed. If the motorcycle topples over, fuel can flow out of the carburetor or fuel tank.

ENVIRONMENT

Riding an off-highway motorcycle is a wonderful form of outdoor recreation and we certainly hope that you and your youngsters will enjoy it to the full. However, this enjoyable outdoor activity can cause environmental problems or lead to conflicts with other people. Responsible use of the motorcycle will prevent such problems and conflicts. You can contribute to securing the future of motorcycling by making sure that you and your youngsters only use the motorcycle within the limits established by the applicable laws, making environmental protection one of your top priorities and never violating other people’s rights.

In this spirit, we hope that you and your youngsters will always safely enjoy your motorcycle!

KTM-SPORTMOTORCYCLE AG 5230 MATTIGHOFEN, AUSTRIA

Attachments: 1 spare parts manual chassis & engine

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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. 35 kg (78 lbs) and a maximum height of 130 cm (51 in).

– Have your youngster wear proper protective gear whenever he or she rides the motorcycle: helmet, eye

protection, chest, back, arm and leg protectors, gloves and boots. To set a good example, be sure to wear protective gear yourself whenever riding a motorcycle!

– Before your youngster takes his or her first ride, explain how each of the controls works and check if

your youngster has understood what you explained. We recommend to review the entire owner’s manual with your youngster item by item, paying particular attention to the specially marked warnings and pointing out the danger of injury.

– Instruct your youngster about riding and falling techniques, explain how the motorcycle will respond

to shifting of the rider’s weight, etc.

– Before starting the motorcycle for the first time check whether the basic fork and shock absorber

settings are suitable for your child's weight (see chapter on checking the basic chassis setting)

– Before using the motorcycle you should always check all components for proper operation (see maine-

nance schedule). Have your youngster perform these technical checks himself / herself as well.

– Whenever you go for a ride with your youngster, keep in mind that the speed should be adjusted to

your youngster and not the other way around.

– Your youngster must understand that all instructions he or she receives from you or any other super-

vising adult must be followed.

– Your child must be physically ready to ride a motorcycle. This means that he or she must at least be

able to ride a bicycle. Being good at sports that require fast reactions is an additional advantage. Your youngster should be strong enough to pick up the motorcycle after a fall.

– Never demand too much of your youngster. Give him or her time to get used to the motorcycle and to

improve his / her riding skills. Do not even consider letting your youngster participate in a race before his / her physical condition, riding skills and motivation have sufficiently developed.

– Explain to your youngster that he / she should always adjust his / her riding speed to the local condi-

tions as well as to his / her own riding skills and that excessive speed can cause falls and severe injuries. Always keep in mind that youngsters tend to underestimate dangers or fail to recognize them

altogether. The riding speed must be reduced, in particular, on unknown terrain. – Never let your youngster ride the motorcycle without supervision. An adult should always be present. – The motorcycle is designed for one rider only. Your youngster is not allowed to transport a passenger. – When you go for a ride, somebody at home should always know where you are going and when you

will be back. This makes it easier to send you help, should problems occur.

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TABLE OF CONTENTS

Page

IMPORTANT INFORMATION FOR PARENTS

ABOUT SAFE DRIVING . . . . . . . . . . . . . . . . . . . . . . . . .4

SERIAL NUMBER LOCATIONS . . . . . . . . . . . . . . . . . . . .6

Chassis number . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Engine number . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

OPERATION INSTRUMENTS . . . . . . . . . . . . . . . . . . . . .7

Throttle grip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Hand brake lever . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Short circuit button . . . . . . . . . . . . . . . . . . . . . . . . .7

Filler cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Fuel tap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Choke (Dell’Orto carburetor PHVA 14 DS) . . . . . . . . . .8

Choke (Dell’Orto carburetor PHBG 19 BS) . . . . . . . . .8

Kickstarter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Foot brake lever . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Side stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Plugin - Stand (50 SX) . . . . . . . . . . . . . . . . . . . . . . .9

Rebound damping function of the shock absorber . . . .9

General Tips and Warnings for starting the motorcycle

. .10

Instructions for the first ride . . . . . . . . . . . . . . . . . .10

Running in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Driving instructions . . . . . . . . . . . . . . . . . . . . . . . . .11

What you should check before each start . . . . . . . . .11

Starting when the engine is cold . . . . . . . . . . . . . . .12

Starting when the engine is warm . . . . . . . . . . . . . .12

What to do when the engine is “flooded” . . . . . . . . .12

Starting off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Driving . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Refueling, fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Braking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Stopping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

PERIODIC MAINTENANCE SCHEDULE . . . . . . . . . . . . .14

MAINTENANCE WORK ON CHASSIS AND ENGINE . . . .16

Removing the seat . . . . . . . . . . . . . . . . . . . . . . . . .16

Checking and adjusting the steering head bearing

(50 SX Junior) . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Checking and adjusting the steering head bearing

(50 SX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

How to change the handlebar position . . . . . . . . . . .17

Basic suspension setup for the weight of the driver . .18

To determine the sag of the shock absorber . . . . . . . .18

To determine the sag of the telescopic fork . . . . . . .18

Telescopic fork maintenance . . . . . . . . . . . . . . . . . .19

Changing the telescopic fork oil . . . . . . . . . . . . . . . .19

Cleaning the dust scrabbers of the telescopic fork . . .20

Page

Changing spring preloading of the shock absorber . . .20

Check chain tension . . . . . . . . . . . . . . . . . . . . . . . .20

Correct chain tension . . . . . . . . . . . . . . . . . . . . . . .20

Chain maintenance . . . . . . . . . . . . . . . . . . . . . . . . .20

General information about KTM disc brakes . . . . . . .21

Setting the basic position and play of the hand brake lever

. .21

Checking the brake fluid level/ refilling . . . . . . . . . . .22

Checking front brake pads . . . . . . . . . . . . . . . . . . . .22

Replacing the front brake pads . . . . . . . . . . . . . . . .22

Changing the basic position of the foot brake lever

(50 SX Junior) . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Adjusting the control cable on the rear wheel (50 SX Junior)

. .23

Checking the rear brake linings for wear (50 SX Junior)

. .23

Drum brake maintenance (50 SX Junior) . . . . . . . . .23

Changing the basic position of the brake lever (50 SX)

. .23

Checking the rear brake fluid level (50 SX) . . . . . . . .23

Refilling the rear brake fluid reservoir (50 SX) . . . . . .24

Checking rear brake pads (50 SX) . . . . . . . . . . . . . .24

Replacing the rear brake pads (50 SX)

. . . . . . . . . . . .24

Removing and mounting the front wheel . . . . . . . . . .25

Removing and mounting the rear wheel . . . . . . . . . .25

Tires, air pressure . . . . . . . . . . . . . . . . . . . . . . . . . .26

Checking spoke tension . . . . . . . . . . . . . . . . . . . . .26

Cooling system . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Checking coolant level . . . . . . . . . . . . . . . . . . . . . .27

Cleaning the air filter . . . . . . . . . . . . . . . . . . . . . . .27

Exhaust system . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Changing the seat height . . . . . . . . . . . . . . . . . . . . .28

Adjusting the throttle cable . . . . . . . . . . . . . . . . . . .28

Adjusting the idle speed (Dell’Orto PHVA 14 DS) . . .28

Adjusting the idle speed (Dell’Orto PHBG 19 BS) . . .28

Checking the gear oil level . . . . . . . . . . . . . . . . . . .29

Changing gear oil . . . . . . . . . . . . . . . . . . . . . . . . . .29

Adjusting the centrifugal clutch . . . . . . . . . . . . . . . .30

TROUBLE SHOOTING . . . . . . . . . . . . . . . . . . . . . . . . .32

CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

TECHNICAL DATA – ENGINE . . . . . . . . . . . . . . . . . . . .35

TECHNICAL SPECIFICATIONS - CHASSIS . . . . . . . . . . .36

HEAD WORD INDEX . . . . . . . . . . . . . . . . . . . . . . . . . .37

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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. Enter this number in the relevant field on page 1.

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OPERATION INSTRUMENTS

Throttle grip

The throttle grip is located on the right side of the handlebars. It is used to reduce the engine speed and, thus, the driving speed.

Hand brake lever

The hand brake lever is located on the right side of the handlebars and actuates the front wheel brake. The basic position can be adjusted to fit your child's hand.

Short circuit button

The short circuit button [1] turns off the engine. When pressing this button, the ignition circuit is short-circuited.

Filler cap

To open it: turn filler cap counter-clockwise. To close it: put filler cap back on and tighten it by turning it clockwise.

Install tank breather hose [2] without kinks.

Fuel tap

The fuel tap [3] 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. Closing the fuel tap: Turn the knob all the way to the right.

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OPERATION INSTRUMENTS

Choke Dell’Orto carburetor PHVA 14 DS (50SX Junior)

Choke lever [1] is mounted to the right side of the carburetor. If you move the choke lever up to the stop, a hole is opened in the carburetor through which the engine can draw in additional fuel. This results in a "rich" fuel-air mixture required for a cold start.

Moving the choke lever back closes the hole in the carburetor again.

Choke Dell’Orto carburetor PHBG 19 BS (50 SX)

Choke control knob [2] 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 in the carburetor through which the engine can draw additional fuel. This results in a "rich" fuel-air mixture required for a cold start. Turning back the choke control knob returns the knob to the starting position and closes the hole in the carburetor again.

Kickstarter

The kickstarter is mounted on the right side of the engine. Its upper part can be swivelled.

Foot brake lever

The foot brake lever is located in front of the right footrest. The basic position can be adjusted to the seating position (see maintenance work).

Side stand (50 SX Junior)

Use your foot to swing the side stand forwards to the stop. Make sure it rests securely on solid ground.

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OPERATION INSTRUMENTS

Plugin - Stand (50 SX)

A socket is provided on the left side of the frame for the plug-in stand [1] included in the scope of supply.

Rebound damping function of the shock absorber

By using the adjusting screw [2], the degree of damping of the rebound can be adjusted. Turn the knob clockwise to increase damping, turn it counterclockwise to reduce damping during rebounding.

STANDARD ADJUSTMENT:

– turn the adjusting screw clockwise to the stop. – then turn the adjusting screw counterclockwise, counting the number of

clicks that corresponds to the respective type of shock absorber.

50 SX Junior: . . . . . . . . . .12

50 SX: . . . . . . . . . . . . . . .10

– Never turn the setting wheel more than two clicks between two test rides. – Do not try to disassemble the shock absorber or to perform maintenance

work yourself. Danger of injury!

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GENERAL TIPS AND WARNINGS FOR STARTING THE MOTORCYCLE

Running in

– Even very precisely machined sections of engine components

have rougher surfaces than components which have been sliding across one another for quite some time. Therefore, every engine needs to be broken in. Do not load the engine to the

power limit during the first half hour for this reason. – Apply low but changing loads for running-in. – NO FULL-LOAD OPERATION DURING THE FIRST HALF HOUR!

– Have your youngster wear proper protective gear whenever he

or she rides the motorcycle: helmet, eye protection, chest, back,

arm and leg protectors, gloves and boots. To set a good exam-

ple, be sure to wear protective gear yourself whenever riding a

motorcycle! – The motorcycle has a centrifugal clutch. The motorcycle begins

to move as soon as the throttle is opened. – Always apply the front brake when starting the engine and release

the brake slowly when the engine is running. An activated

choke increases the idle speed of the engine, the centrifugal

clutch thus beginning to engage. Therefore, the motorcycle can

begin to move when the brake levers are released. – When the engine speed drops to the level at which the cen-

trifugal clutch disengages, braking with the engine is no longer

possible and the motorcycle can only be slowed down using

the brakes. – Your child should never drive faster than its skills and the ter-

rain permit. – Never let your child drive its motorcycle unchaperoned. – Replace the helmet visor or goggle glasses early enough. When

light shines directly on a scratched visor or goggles, you will

be practically blind. – 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. Therefore, they are not per-

mitted on public roads. – Always keep in mind that other people feel molested by exces-

sive noise.

Instructions for the first ride

– Make sure the work for the "pre-delivery inspection" was per-

formed by your authorized KTM workshop. The DELIVERY CERTIFICATE and SERVICE MANUAL will be handed over when you pick up your vehicle.

– Before your youngster takes his or her first ride, explain how

each of the controls works and check if your youngster has understood what you explained. We recommend to review the entire owner’s manual with your youngster item by item, paying particular attention to the specially marked warnings and pointing out the danger of injury.

– Adjust the basic position of the hand brake lever to fit the size

of your child's hand. You child should of course wear gloves. Adjust the foot brake lever to your child's seating position.

– To prevent injury, teach your youngster the basic riding skills

on soft ground, e.g. on a meadow or in the garden. Be sure that there is room enough to maneuver, and that no other riders are close.

– To ensure that your youngster gets the feel of the brakes, have

your youngster operate the brakes while you push the motorcycle. Do not start the engine before your youngster has learned to apply both brakes with appropriate pressure.

– Now your youngster must get the feel of the throttle. Start the

engine, hold the motorcycle and have your youngster slowly open the throttle. Then, your youngster can take his/her first ride. Initially, your youngster should ride back and forth between two persons who help the young rider to stop the motorcycle. However, you should also teach your youngster how to stop the motorcycle himself/herself.

– To improve his/her riding skills, your youngster should practise

to ride the motorcycle standing on the footpegs or riding at the slowest possible speed. Additionally, you can arrange a series of obstacles and have your youngster drive around them, etc.

– Tell your youngster to look 3-10 m ahead, depending on the

speed, to recognize and avoid obstacles. When riding through curves, the rider should also look far ahead into the curve.

– Pay attention to running-in procedure.

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DRIVING INSTRUCTIONS

What you should check before each start

When you start off, the motorcycle must be in a perfect technical condition. For safety reasons, you should make it a habit to perform an overall check of your motorcycle before each start.

The following checks should be performed:

1 CHECK TRANSMISSION OIL LEVEL

A lack of gear oil leads to premature wear and finally results in destruction of the gear wheels.

2 FUEL

Check that there is sufficient fuel in the tank; when closing the filler cap, check that the tank venting hose is free of kinks.

3 COOLING FLUID

Check the level of cooling fluid when the engine is cold.

4 CHAIN

A loose chain was fall off the chain wheels; an extremely worn chain may tear, and insufficient lubrication may result in unnecessary wear of the chain and chain wheels.

5 TIRES

Check for damaged tires. Tires showing cuts or dents must be replaced. Also check the air pressure. Insufficient tread and incorrect air pressure deteriorate the driving performance.

6 BRAKES

Check for proper functioning, check brake fluid level in the tank. The tank is designed such that it does not need to be refilled, even if the brake shoes are worn. 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. Check the play of the hand brake lever and foot brake lever.

7 THROTTLE CABLE

Check the throttle cable for proper adjustment and smooth operation.

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DRIVING INSTRUCTIONS

Starting when the engine is cold

1 Open fuel tap [1]. 2 Operate the choke [2]. 3 Kick the side up all the way or remove the plug-in stand. 4 Apply the front brake. 5 Operate the kickstarter, depressing it all the way, without opening the throt-

tle.

– When starting the engine, put on motorcycle boots in order to avoid

injuries. You may slip off the kickstarter, or the engine may kick back if you do not kick hard enough.

– Do not start the engine and allow it to idle in a closed area. Exhaust fumes

are poisonous and can cause loss of consciousness and death. Always provide adequate ventilation while the engine is running.

Don’t ride your motorcycle with full load and high revs when engine is cold. Because the piston is warming up faster than the water cooled cylinder, it can cause engine damage.

NOTE: The highly inflammable components in modern fuels volatilize if left standing 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 start up immediately if the float chamber is filled with fresh, ignitable fuel

Starting when the engine is warm

1 Open fuel tap [1]. 2 Kick the side up all the way or remove the plug-in stand. 3 Apply the front brake. 4 Operate the kickstarter, depressing it all the way, without opening the throt-

tle.

What to do when the engine is “flooded”

1 Close fuel tap [1]. 2 Applying the front brake. 3 Start engine with full throttle. If necessary, unscrew spark plug and

dry it.

4 Once the engine is running, open fuel tap again.

Starting off

Slowly release the brake lever while simultaneously opening the throttle.

Always make sure the side stand is kicked all the way up or the plug-in stand removed before you let your child drive off. The motorcycle could run out of control if the stand touches the ground.

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