KTM 50 SX PRO JUNIOR LC User Manual

OWNER`S MANUAL
MANUALE D`USO
MANUEL D`UTILISATION
MANUAL DE INSTRUCCIONES

ART.NR: 3.211.35

50 SX PRO JUNIOR LC
50 SX PRO SENIOR LC

BEDIENUNGSANLEITUNG2005

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1

IMPORTANT »

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.

© 2004 by KTM-SPORTMOTORCYCLE AG, Mattighofen AUSTRIA; All rights reserved; Reprint, also in
extracts, with written allowance of KTM-SPORTMOTORCYCLE AG, Mattighofen only.

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:

– IGNORING THESE INSTRUCTIONS CAN BE DANGEROUS TO LIFE AND LIMB!

– IGNORING THESE INSTRUCTIONS MAY DAMAGE PARTS OF THE MOTORCYCLE OR IMPAIR THE MOTOR-

CYCLE’S TRAFFIC SAFETY!

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INTRODUCTION »

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

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.
Be sure to have the maintenance work carried out by a KTM workshop to avoid losing your right to claim
under the warranty.

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.

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.

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 WARRANTY AND GUARANTEE INFORMATION »

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.

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 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.

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.

No claims can be filed under the warranty for damage or consequential damage caused by manipulations
or conversions to the motorcycle.

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.

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 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 mai-

nenance 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 (SENIOR LC) . . . . . . . . . . . . . . . . . . .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 (JUNIOR LC)

16

Checking and adjusting the steering head bearing (SENIOR LC)

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

Page

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

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

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

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 (Junior LC)

23

Adjusting the control cable on the rear wheel (Junior LC)

23

Checking the rear brake linings for wear (Junior LC) . .23

Drum brake maintenance (Junior LC) . . . . . . . . . . . .23

Changing the basic position of the brake lever (SeniorLC)

23

Checking the rear brake fluid level (Senior LC) . . . . .23

Refilling the rear brake fluid reservoir (Senior LC) . . .24

Checking rear brake pads (Senior LC) . . . . . . . . . . . .24

Replacing the rear brake pads (Senior LC) . . . . . . . .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

TROUBLE SHOOTING . . . . . . . . . . . . . . . . . . . . . . . . .30

CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

TECHNICAL DATA – ENGINE . . . . . . . . . . . . . . . . . . . .33

TECHNICAL SPECIFICATIONS - CHASSIS . . . . . . . . . . .34

HEAD WORD INDEX . . . . . . . . . . . . . . . . . . . . . . . . . .35

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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.

1

2

3

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OPERATION INSTRUMENTS »

Choke (Dell’Orto carburetor PHVA 14 DS)

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)

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

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

1

2

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OPERATION INSTRUMENTS »

Plugin - Stand (SENIOR LC)

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

The damping effect of the rebound damping mechanism can be adjusted by
means of the setting wheel [2]. Turn the setting wheel clockwise (in) to
increase and counterclockwise (out) to reduce the damping effect.

STANDARD SETTING: 5 CLICKS OPEN

– 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!

1

2

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GENERAL TIPS AND WARNINGS FOR STARTING THE MOTORCYCLE »

– 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!

– THE MOTORCYCLE HAS A CENTRIFUGAL CLUTCH. THE MOTOR-

CYCLE 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

CENTRIFUGAL 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 TERRAIN PERMIT.

– NEVER LET YOUR CHILD DRIVE ITS MOTORCYCLE UNCHAPER-

ONED.

– 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 PERMITTED ON PUBLIC ROADS.
– ALWAYS KEEP IN MIND THAT OTHER PEOPLE FEEL MOLESTED

BY EXCESSIVE NOISE.

Instructions for the first ride

– Verify that your KTM dealer performed the PREPARATION

OF VEHICLE jobs (see Customer Service Manual).

– 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.

Running in

– Even very precisely machined sections of engine compo-

nents 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!

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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 throttle.

– 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.

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 throttle.

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.

Driving

The engine speed, and thus the driving speed, are regulated by the throttle
grip.
The choke must always be deactivated as soon as the engine has warmed up.

– AFTER FALLING WITH THE MOTORCYCLE, CHECK ALL ITS FUNCTIONS

THOROUGHLY BEFORE USING IT AGAIN.

– A BENT HANDLEBAR MUST ALWAYS BE REPLACED. NEVER TRY TO STRAIGHTEN

THE HANDLEBAR BECAUSE THIS WILL CAUSE IT TO LOSE ITS STABILITY.

1

2

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13

DRIVING INSTRUCTIONS »

– DRIVING A COLD ENGINE AT HIGH SPEED WILL REDUCE THE

LIFE OF THE ENGINE. WE RECOMMEND TO WARM THE ENGINE
UP AT A MEDIUM ENGINE SPEED FOR SEVERAL MINUTES
BEFORE SWITCHING TO FULL LOAD.

– NEVER TILT THE MOTORCYCLE OVER THE SIDE STAND TO WARM

UP THE ENGINE. THE SIDE STAND COULD FOLD AWAY AND THE
MOTORCYCLE RUN OUT OF CONTROL.

– IN THE EVENT THAT, WHILE YOUR CHILD IS RIDING ON THE

MOTORCYCLE, YOU NOTICE ANY UNUSUAL OPERATION-RELATED
NOISE, YOUR CHILD SHOULD STOP IMMEDIATELY, TURN THE
ENGINE OFF, AND CONTACT AN AUTHORIZED KTM DEALER.

Braking

Close the throttle and squeeze both brake levers simultaneously.
On sandy, wet or slippery terrain the rear wheel brake should be
preferred. The brakes should always be operated carefully as
locking wheels can cause skidding or falls.

– BRAKE DRUM AND LININGS HEAT UP DURING BRAKE OPERA-

TION, THUS REDUCING THE EFFECT OF THE BRAKES.

– WET BRAKES HAVE REDUCED BRAKE PERFORMANCE, THERE-

FORE BE SURE TO BRAKE THEM DRY AFTER CLEANING.

– IF THE RESISTANCE OF THE HAND BRAKE LEVER FEELS UNRE-

SPONSIVE, SOMETHING IS WRONG WITH THE BRAKE SYSTEM.
HAVE THE BRAKE SYSTEM CHECKED AT A KTM WORKSHOP
BEFORE YOU LET YOUR CHILD DRIVE THE MOTORCYCLE.

Stopping

Reduce the speed. Immediately before the motorcycle comes
to a stop, put the left foot down. To turn off the engine, press
the short circuit button until the engine stops. Close the
fuel tap.

MOTORCYCLES PRODUCE GREAT HEAT DURING OPERATION.
THEREFORE, KEEP IN MIND THAT THE ENGINE, THE EXHAUST
SYSTEM AND THE BRAKES CAN HEAT UP CONSIDERABLY. MAKE SURE
THAT THESE PARTS ARE NOT TOUCHED AND ALWAYS TAKE CARE,
WHEN PARKING THE MOTORCYCLE, THAT OTHER PERSONS WILL
NOT BURN THEMSELVES.

– CLOSE THE FUEL TAP WHEN LEAVING THE MOTORCYCLE.

OTHERWISE THE CARBURETOR MAY GET FLOODED AND FUEL
WILL ENTER THE ENGINE.

– THE SIDE STAND OR PLUG-IN STAND IS DESIGNED TO HOLD

THE WEIGHT OF THE MOTORCYCLE ONLY. BY SITTING ON THE
MOTORCYCLE, YOUR CHILD WILL PUT ADDITIONAL WEIGHT ON
THE SIDE STAND, POSSIBLY CAUSING THE SIDE STAND OR
FRAME TO BE DAMAGED OR THE MOTORCYCLE TO FALL DOWN.

Refueling, fuel

Oil (high-grade two-stroke engine oil) must be mixed with the
fuel (ROZ 95) at a mixing ratio of 1:40.

Fuel and engine oil should only be mixed immediately before
use.KTM recommends Motorex 2T Cross Power.

GASOLINE IS HIGHLY FLAMMABLE AND POISONOUS. EXTREME
CAUTION SHOULD BE USED WHEN HANDLING GASOLINE. NEVER
REFUEL THE MOTORCYCLE NEAR OPEN FLAMES OR BURNING
CIGARETTES. ALWAYS SWITCH OFF THE ENGINE BEFORE REFUEL­ING. BE CAREFUL NOT TO SPILL GASOLINE ON THE ENGINE OR
EXHAUST PIPE WHILE THE ENGINE IS HOT. WIPE UP SPILLS
PROMPTLY. IF GASOLINE IS SWALLOWED OR SPLASHED IN THE EYES,
SEEK A DOCTOR’S ADVICE IMMEDIATELY.

– ONLY USE PREMIUM-GRADE GASOLINE ROZ 95 MIXED WITH

HIGH-GRADE TWO-STROKE ENGINE OIL. OTHER TYPES OF GASO­LINE CAN CAUSE ENGINE FAILURE.

– ONLY USE KNOWN BRANDS OF HIGH-GRADE 2-STROKE ENGINE

OIL (MOTOREX 2T CROSS POWER).

– NOT ENOUGH OIL OR LOW-GRADE OIL CAN CAUSE EROSION OF

THE PISTON. WHEN USING TOO MUCH OIL, THE ENGINE MAY
START SMOKING AND FOUL THE SPARK PLUG.

– FUEL EXPANDS WHEN ITS TEMPERATURE RISES. THEREFORE

DO NOT FILL THE TANK TO THE TOP. (SEE FIG.)

40 mm

ENGLISH

14

PERIODIC MAINTENANCE SCHEDULE »

A CLEAN MOTORCYCLE CAN BE CHECKED MORE QUICKLY WHICH SAVES MONEY!

Service
every
5 hours

Service
every
20 hours

Engine

Check engine for leaks z
Change transmission oil z
Check spark plug, change it if necessary, set electrode gap z

Carburetor

Check carburetor for a tight fit at intake flange z
Check intake flange for cracks z
Check idle setting when engine is warm z

Add-On-Parts

Check cooling system for leaks, check quantity of antifreeze z
Check exhaust system for leaks and suspension z
Check actuating cables for damage, smooth operation, and kinkless arrangement, adjust and lubricate z
Clean air filter and air filter box z

Brakes

Check brake fluid level, lining thickness, brake discs z
Check the brake line and the brake control cable for damage z
Check/function adjust smooth operation, free travel of handbrake/footbrake levers z
Check screws of brake system for a tight fit z

Chassis

Check suspension strut and fork for leaks and a proper function z
Check swinging-fork pivot z
Check/adjust steering-head bearing z
Check all chassis screws for a tight fit (fork plates, axle nuts, swinging-fork pivot, suspension strut) z

Wheels

Check spoke tension and rim joint z
Check tire condition and inflation pressure z
Check chain, chain joint, chain wheels, chain wheel guides for wear, a tight fit, and tension z
Lubricate chain z
Check wheel bearings for play z

IMPORTANT RECOMMENDED MAINTENANCE PROCEDURES TO BE PERFORMED BASED ON A SEPARATE SUPPLEMENTARY ORDER

once a
year

Drain and clean the carburetor's float chamber z
Perform complete fork maintenance z
Clean and lubricate the swinging-arm bearing z

Clean and lubricate the steering-head bearing and sealing elements

z

Change brake fluid

z

MAINTENANCE WORK DONE BY KTM AUTHORISED WORKSHOPS IS NOT A SUBSTITUTE FOR CARE AND CHECKS DONE BY
THE RIDER!

50 SX PRO SENIOR LC

50 SX PRO JUNIOR LC

2005

ENGLISH

15

PERIODIC MAINTENANCE SCHEDULE »

VITAL CHECKS AND CARE PROCEDURES TO BE CONDUCTED BY THE OWNER OR THE MECHANIC

before
each start

after
every
cleaning

for cross
country
use

once a
year

Check transmission oil level z
Check cooling liquid level z
Check brake fluid level z
Check brake pads for wear z
Check brake performance z z
Lubricate and adjust actuating cables and nipples z
Remove and clean dust sleeves of telescopic fork at regular intervals z
Clean and lubricate chain, check tension and readjust it if necessary z z
Clean air filter and filter box z
Check tire inflation pressure and wear z
Check fuel line for leaks z
Drain and clean float chamber z
Verify smooth operation of all controls z

Treat exposed metal components (except for the brake and exhaust systems)
with wax-based anti-corrosion agents

z

Check all screws, nuts, and hose clamps for their tight fit at regular intervals

z

RECOMMENDED INSPECTION OF THE MINI LC ENGINE BY YOUR KTM WORKSHOP (ADDITIONAL ORDER FOR THE KTM WORKSHOP)

30
hours

45
hours

60
hours

90
hours

120
hours

135
hours

Check the reed-type intake valve for wear z z z z z z
Check the clutch shoes for wear z z z z z z
Check the clutch drum for wear z z z z z z
Check the water pump shaft and bearings for wear z z z z z z
Check the water pump wheel for wear z z z z z z
Check the cylinder and piston for wear z z z z z z
Check the eccentricity of the crankshaft journal z z z z z z
Check the radial clearance of the conrod bearings z z z
Check the radial clearance of the piston pin main bearing z z z
Check the crankshaft main bearing for wear z z z
Replace the crankshaft bearings and conrod bearings z z z
Check the entire transmission including bearings for wear z z

z

NOTE: IF THE INSPECTION ESTABLISHES THAT PERMISSIBLE TOLERANCES ARE EXCEEDED, THE RESPECTIVE COMPONENTS

MUST BE REPLACED.

ENGLISH

16

MAINTENANCE WORK ON CHASSIS AND ENGINE »

Removing the seat

The quick-release mechanism [1] allows removal of the seat without tools.
Turn the quick-release device approximately 180° counterclockwise, lift the
rear portion of the seat and pull the seat off backwards.
When mounting the seat ensure that the hook engages at the tank.

Checking and adjusting the steering head bearing (JUNIOR LC) *

The steering head bearing should be checked regularly for play. For this
purpose, jack up the motorcycle by the frame so that the front wheel is in the
air. Now try to move the fork forward and backward. There should be no clear­ance. For readjustment, release the two clamp screws [2] of the top triple
clamp and the counternut [3]. Turn the adjusting nut [4] until almost no play
is left. Do not tighten the adjusting nut! Tightening the adjusting nut can
damage the bearings! Keep in mind that tightening the
counternut [3] reduces the play of the bearing. Slightly tap the top triple clamp
with a rubber hammer to prevent jamming. Then tighten the 2 clamp screws
with 20 Nm.

IF THE STEERING HEAD BEARING IS NOT ADJUSTED TO BE FREE OF CLEARANCE,
THE MOTORCYCLE WILL EXHIBIT UNSTEADY DRIVING CHARACTERISTICS AND
CAN GET OUT OF CONTROL.

– THE HANDLEBAR MUST MOVE EASILY. OTHERWISE THE BEARINGS WILL BE

DAMAGED.

– IF YOU DRIVE WITH PLAY IN THE STEERING HEAD BEARING FOR LONGER

PERIODS, THE BEARINGS AND SUBSEQUENTLY THE BEARING SEATS IN THE
FRAME WILL BE DESTROYED.

At least once a year, the steering head bearings should be smeared with water­proof grease (Motorex Long Therm 2000).

1

2

3

4

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.

– WHEN CLEANING THE MOTORCYCLE, DO NOT USE A HIGH PRESSURE CLEANING UNIT IF POSSIBLE, OTHERWISE WATER

WILL PENETRATE THE BEARINGS, CARBURETOR, ELECTRIC CONNECTORS, DRUM BRAKES, ETC.
– BEFORE CLEANING WITH WATER, PLUG THE EXHAUST PIPE TO PREVENT WATER INGRESS
– 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.
– DO NOT USE TOOTHED WASHERS OR SPRING RINGS WITH THE ENGINE FASTENING SCREWS, AS THESE WORK INTO THE

FRAME PARTS AND KEEP WORKING LOOSE. INSTEAD, USE SELF-LOCKING NUTS.
– LET YOUR MOTORCYCLE COOL DOWN BEFORE BEGINNING ANY MAINTENANCE WORK IN ORDER TO AVOID GETTING BURNED.
– DISPOSE OF OILS, FATTY MATTERS, FILTERS, FUELS, WASHING DETERGENTS, ETC. PROPERLY.
– UNDER NO CIRCUMSTANCES MAY USED OIL BE DISPOSED OF IN THE SEWAGE SYSTEM OR IN THE OPEN COUNTRYSIDE.

1 LITER OF USED OIL CONTAMINATES 1,000,000 LITERS OF WATER.

3

4

2

ENGLISH

17

MAINTENANCE WORK ON CHASSIS AND ENGINE »

Checking and adjusting the steering head bearing (SENIOR LC) *

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 – you should not feel any play. To adjust,
loosen both clamping screws [1] on the upper triple clamp and loosen the
steering head screw [2] by a few turns. Lift the triple clamp slightly and turn
the adjusting nut [3] until hardly any play is left. Never tighten the adjusting
nut since you might damage the bearing. Tighten the steering head screw to
a torque of 10 Nm and the 2 clamping screws to 20 Nm.

IF THE STEERING HEAD BEARING IS NOT ADJUSTED TO BE FREE OF CLEARANCE,
THE MOTORCYCLE WILL EXHIBIT UNSTEADY DRIVING CHARACTERISTICS AND
CAN GET OUT OF CONTROL.

– THE HANDLEBAR MUST MOVE EASILY. OTHERWISE THE BEARINGS WILL BE

DAMAGED.

– IF YOU DRIVE WITH PLAY IN THE STEERING HEAD BEARING FOR LONGER

PERIODS, THE BEARINGS AND SUBSEQUENTLY THE BEARING SEATS IN THE
FRAME WILL BE DESTROYED.

At least once a year, the steering head bearings should be smeared with water­proof grease (Motorex Long Therm 2000).

How to change the handlebar position

The handlebar position can be readjusted by 22 mm (0.9 in). The upper triple
clamp [4] includes 2 bores arranged at a distance of 15 mm (0.6 in) from
one another. The bores at the handlebar support [5] are offset from the
center by 3.5 mm (0.13 in). Accordingly, you can mount the handlebar in 4
different positions.

For this purpose, remove screws [6] of the handlebar clamps and screws [7]
of the handlebar support. Position handlebar support, and tighten screws [7]
to 40 Nm. Mount handlebar and handlebar clamps, and tighten screws [6]
to 20 Nm. The gap between the handlebar support and handlebar clamps
should be the same size in the front and in the rear.

THE SCREWS [7] MUST BE SECURED WITH LOCTITE 243.

2

1

3

2

1

3

15 mm

3,5 mm

6

7

4

5

ENGLISH

18

MAINTENANCE WORK ON CHASSIS AND ENGINE »

Basic suspension setup for the weight of the driver

To achieve maximum handling performance and to prevent the telescopic fork
and shock absorber from being damaged, the basic setup of the suspension
components must be suitable for your child's weight. At delivery, KTM's mini
motorcycles are set to accommodate a driver weighing 25 - 30 kg (wearing
full protective clothing). If your child's weight exceeds or falls short of this
range, you will need to adjust the spring preload for the telescopic fork and
shock absorber accordingly.
To adjust, check the sag of the shock absorber and telescopic fork. The motor­cycle should be filled up and your child should be wearing full protective
clothing.

To determine the sag of the shock absorber

– Jack up the motorcycle until the rear wheel no longer touches the ground.
– Measure the vertical distance between the rear wheel axle and a fixed

point (e.g. a mark on the side cover) and write it down as dimension A.
– Place the motorcycle on the ground again.
– Have your child sit on the motorcycle in a normal seating position

(feet on the footrests) wearing full protective clothing and bounce up and

down a few times to allow the rear wheel suspension to become level.
– Holding your child and the bike, have another person measure the

distance between the same two points with the load on the motorcycle to

establish dimension B.
– The sag is the difference between dimensions A and B.

EXAMPLE:

Motorcycle jacked up (dimension A) . . . . . . . . . . . . . . . . . . . . . .400 mm

Motorcycle on ground with driver seated (dimension B)

. . . . . . .– 355 mm

Sag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 mm

50 SX Pro Junior LC shock absorber sag . . . . . . . . . . . . 45 mm (± 5 mm)

50 SX Pro Senior LC shock absorber sag . . . . . . . . . . . . 50 mm (± 5 mm)

If the sag is lower, the spring preload of the shock absorber must be reduced,
if the sag is higher, the spring preload must be increased (see Changing spring
preloading of the shock absorber). A harder spring is also available for the 50
SX Pro Senior LC (see spare parts catalog).

To determine the sag of the telescopic fork

– Jack up the motorcycle until the rear wheel no longer touches the ground.
– Measure the distance between the upper edge of the slider tube and the

triple clamp and write it down as dimension C.
– Have your child sit on the motorcycle in a normal seating position

(feet on the footrests) wearing full protective clothing, and bounce up and

down a few times to allow the telescopic fork to become level.
– Holding your child and the bike, have another person measure the

distance between the same two points with the load on the motorcycle to

establish dimension D.
– The sag is the difference between dimensions C and D.

EXAMPLE:

Motorcycle jacked up (dimension C) . . . . . . . . . . . . . . . . . . . . . .200 mm

Motorcycle on ground with driver seated (dimension D)

. . . . . . .– 160 mm

Sag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 mm

50 SX Pro Junior LC telescopic fork sag . . . . . . . . . . . . 30 mm (± 5 mm)

50 SX Pro Senior LC telescopic fork sag . . . . . . . . . . . . 45 mm (± 5 mm)

If the sag is lower, the spring preload of the telescopic fork must be reduced,
if the sag is higher, the spring preload must be increased.

The preload on the fork spring is determined by the length of preload spacer
[1]. If an adjustment is necessary, demount the fork legs, remove the plugs
and shorten the pretensioning sleeves or replace with longer ones
(see maintenance of telescopic fork). Harder fork springs are also available
for both models (see spare parts catalog).

1

A

B

C

D

A

B

C

D

ENGLISH

19

MAINTENANCE WORK ON CHASSIS AND ENGINE »

Telescopic fork maintenance *

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 [1] from the brake caliper and
unscrew holding clamp. Measure the projection of the fork legs at the upper
fork stabilizer and make a note of the measurement.
Loosen the clamping screws [2] on the fork stabilizers and pull the fork legs
down out of the fork stabilizers.

– Do not operate the hand brake when the front wheel has been

dismounted.
– Make sure the brake disc is always on top when you lay down the wheel,

otherwise the brake disc can be damaged.

Clamp the fork leg into a vise (use protective jaws) and remove the
plugs [3]. Take the preload spacer and the spring out of the fork tube.
Remove screws [4] at the underside of the slider tubes and pull the fork tubes
out of the slider tubes.
Remove the dust scrabbers [5].

Thoroughly clean all parts and check for wear.
Generously lubricate seals and springs and reassemble the telescopic fork.
Tighten the screws on the bottom of the sliding tubes to 30 Nm.
Fill in fork oil and assemble the fork (see below). Degrease the screws on the
brake caliper and apply Loctite 243. Mount the brake caliper and tighten to
20 Nm. Mount brake line and holding clamp.
Insert fork legs in the fork stabilizers (projection as previously noted) and tighten
clamping screws to 20 Nm (top) and 15 Nm (bottom).
Mount front wheel (see chapter: mounting the front wheel).

THE SCREWS [1] MUST BE SECURED WITH LOCTITE 243.

Changing the telescopic fork oil *

Remove front wheel and fork legs (see above).
Remove plugs, preload spacers and springs.
Drain the fork oil into an appropriate container.
Clean the dust scrabbers.

– It is very important to keep the brake disk free from oil and fatty matters.

Otherwise, the braking effect would be strongly reduced.
– After working on the brake system, always operate the hand brake lever

to apply the brake shoes to the brake disk and have a point of pressure.

Pour 170 cm3 SAE 7.5 fork oil into each fork tube.
Slide the fork tube all the way into the slider tube.
Adjust the air-chamber length A to 110 mm (4.5 in) by extracting or adding
fork oil.
Insert springs and pretensioning sleeves into the fork tube.
Check O-rings, grease and mount plugs.
Mount the fork legs, front wheel and brake caliper (see above).

1

1

2

2

3

4

5

A

ENGLISH

20

MAINTENANCE WORK ON CHASSIS AND ENGINE »

Cleaning the dust scrabbers of the telescopic fork

The dust-protection bellows [1] are to remove dust and coarse dirt particles
from the fork tube. However, after some time, dirt may also get in behind the
dust-protection bellows. If this dirt is not removed, the oil sealing rings located
behind it may start to leak.
For this purpose, use a screwdriver to lift the dust scrabbers out of the
slider tubes, clean them thoroughly with compressed air, spray the fork tubes
and dust scrabbers with silicon oil and press the scrabbers back into the slider
tubes.

NO SILICONE OIL MAY REACH THE FRONT TIRE OR THE BRAKE DISKS SINCE THIS
WOULD CONSIDERABLY REDUCE THE TIRE'S ROAD GRIP AND THE BRAKING
EFFECT OF THE FRONT BRAKE.

Changing spring preloading of the shock absorber

This is easily done.
NOTE: Before changing the spring preload note down the basic setting, e.g.
how many threads are visible above the adjusting ring.

Remove the right side cover.
Loosen the locking ring [2] with the hook spanner. Change the spring preload
with the adjusting ring [3] and re-tighten the locking ring [2].

BASIC SETTING – SPRING PRELOAD:
JUNIOR LC: 10 mm (0.39 in)
SENIOR LC: 7 mm (0.3 in)

Check chain tension

Put the motorcycle on the sidestand.
Chain tension has to be checked close to the lower rear shock mounting [A].
When pushing the chain upwards, the distance to the swingarm has to be
10 mm (0.4 in).
If necessary, correct chain tension.

– IF CHAIN TENSION IS TOO GREAT, PARTS WITHIN THE SECONDARY TRANS-

MISSION (CHAIN, CHAIN WHEELS, GEAR BOX AND REAR WHEEL BEARINGS)
WILL BE SUBJECTED TO UNNECESSARY STRESS, RESULTING IN PREMATURE
WEAR AND EVEN CHAIN BREAKAGE.

– TOO MUCH SLACK IN THE CHAIN, ON THE OTHER HAND, CAN RESULT IN THE

CHAIN JUMPING OFF THE CHAIN WHEELS. IF THIS HAPPENS, THE CHAIN COULD
ALSO BLOCK THE REAR WHEEL OR DAMAGE THE ENGINE. IN EITHER CASE
THE OPERATOR IS LIKELY TO LOSE CONTROL OF THE MOTORCYCLE.

– BE CAREFUL NOT TO GET YOUR FINGER CAUGHT BETWEEN THE CHAIN AND

THE REAR SPROCKET OR OTHER COMPONENTS.

Correct chain tension

Release the hexagon nut of the wheel spindle [4] and turn the left and the
right hexagon nut [5] equally far.
Before tightening the hexagon nut of the wheel spindle to 40 Nm, ensure that
the supporting plates [6] are resting against the swing arm. Additionally,
check that the rear wheel is aligned with the front wheel.

Chain maintenance

For long chain life, good maintenance is very important. Chains without
O-rings should be cleaned in fireproof solvent regularly and afterwards
treated with hot grease or chain spray (Motorex Chainlube Racing).

KEEP THE REAR WHEEL FREE OF GREASE! GREASE ON THE REAR WHEEL WILL
SIGNIFICANTLY REDUCE THE GRIP OF THE REAR TIRE AND THE MOTORCYCLE COULD
EASILY GET OUT OF CONTROL.

WHEN MOUNTING THE CHAIN MASTERLINK CLIP, THE CLOSED SIDE OF THE
MASTERLINK CLIP MUST POINT IN RUNNING DIRECTION.

Also check sprockets and chain guides for wear, and replace if necessary.

1

2

3

5

6

4

6

5

10 mm

A

ENGLISH

21

MAINTENANCE WORK ON CHASSIS AND ENGINE »

General information about KTM disc brakes

BRAKE FLUID RESERVOIRS:
The brake fluid reservoirs for the front brake is designed such that it does not
need to be refilled, even if the brake shoes are worn. If the brake fluid level
drops below the minimum level either the brake system has a leak or the brake
pads are completely worn.
In this case, consult an authorized KTM dealer immediately.

BRAKE FLUID:
KTM fills the brake system with ”Motorex Brake Fluid DOT 5.1”, one of the
best brake fluids currently available. We recommend that you continue to use
it. DOT 5.1 brake fluid is based on glycol ether and of an amber color. If you
do not have any DOT 5.1 for refilling, you may use DOT 4 brake fluid. DOT 4
shown on the lid means minimum standard. However, you should replace it
as soon as possible by DOT 5.1.

HAVE THE BRAKE FLUID CHANGED AT LEAST ONCE ANNUALLY. IF YOU WASH YOUR
MOTORCYCLE OFTEN, THE BRAKE FLUID SHOULD BE CHANGED EVEN MORE
FREQUENTLY. BRAKE FLUID TENDS TO ABSORB WATER. THEREFORE, VAPOR
POCKETS MAY FORM IN "OLD" BRAKE FLUIDS EVEN AT LOW TEMPERATURES,
CAUSING THE BRAKE SYSTEM TO FAIL.

BRAKE DISC:
Due to wear, the thickness of the brake disc in the area of the contact
face [1] of the brake pads decreases. The brake disk must be at least 2.50
mm thick at the thinnest point [A]. Check the thickness of the brake disk at
several points.

– A BRAKE DISK WORN DOWN TO LESS THAN 2.50 MM IS A SAFETY RISK. HAVE

THE BRAKE DISK REPLACED AS SOON AS IT REACHES THE SERVICE LIMIT.

– HAVE ANY REPAIRS ON THE BRAKE SYSTEM BE PERFORMED BY A KTM

DEALER.

BRAKE CALIPERS:
Secure the screws on the brake caliper with Loctite 243 and tighten to a torque
of 20 Nm.

Setting the basic position and play of the hand brake lever *

You can adjust the basic position of the hand brake lever to fit your child's
hand by turning stop screw [2]. Afterwards, be sure to adjust the play of the
hand brake lever to 2 mm (0.08 in)with the adjusting screw [3]. To adjust,
remove covering cap [4]. Replace the covering cap after making the adjust­ment.

AT THE HAND BRAKE LEVER, FREE TRAVEL MUST AT LEAST BE 2 MM (0.08 IN).
ONLY THEN MAY THE PISTON IN THE HAND BRAKE CYLINDER BE MOVED (TO BE
RECOGNIZED BY THE GREATER RESISTANCE OF THE HAND BRAKE LEVER). IF THIS
FREE TRAVEL IS NOT PROVIDED, PRESSURE WILL BUILD UP IN THE BRAKING
SYSTEM, AND THE FRONT-WHEEL BRAKE MAY FAIL DUE TO OVERHEATING.

1

A

min. 2 mm

2

3

4

ENGLISH

22

MAINTENANCE WORK ON CHASSIS AND ENGINE »

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. Move the hand brake cylinder in a horizontal position, remove
the screws [1] and the cover [2] with the diaphragm [3]. The brake fluid level
should be 5 mm below the upper edge of the reservoir (see drawing),
otherwise add DOT 5.1 brake fluid (e.g. Motorex Brake Fluid DOT 5.1) up to
5 mm below the upper edge of the reservoir.
Mount the diaphragm, the cover and the screws and actuate the hand brake
lever until you feel the point of pressure again. Wipe off any overflowing or
spilled brake fluid with water.

– ACTUATE THE HAND BRAKE LEVER UNTIL YOU FEEL THE POINT OF PRESSURE

AGAIN.

– NEVER USE DOT 5 BRAKE FLUID! IT IS BASED ON SILICONE OIL AND OF A

PURPLE COLOR. SEALS AND BRAKE HOSES MUST BE ESPECIALLY ADAPTED

TO IT.
– STORE BRAKE FLUID OUT OF REACH OF CHILDREN.
– BRAKE FLUID CAN CAUSE SKIN IRRITATION. AVOID CONTACT WITH SKIN AND

EYES. IF YOU GET BRAKE FLUID IN YOUR EYES, RINSE WITH PLENTY OF WATER

AND CONSULT A DOCTOR.

– DON’T LET BRAKE FLUID GET IN CONTACT WITH PAINT, IT IS AN EFFECTIVE

PAINT REMOVER.
– USE ONLY CLEAN BRAKE FLUID TAKEN FROM A TIGHTLY SEALED CONTAINER.

Checking front brake pads

Inspect the brake pads from in front of the vehicle. The linings must be at
least 1 mm (0.04 in) thick.

AT THEIR MOST WORN POINT BRAKE PAD LININGS SHOULD NOT BE THINNER
THAN 1 MM (0.04 IN), OTHERWISE THEY COULD LEAD TO BRAKE FAILURE. FOR
YOUR OWN SAFETY DON’T PUT OFF HAVING YOUR BRAKE PADS CHANGED.

IF THE BRAKE PADS ARE REPLACED TOO LATE SO THAT THE LINING IS PARTLY
OR ENTIRELY WORN, THE STEEL COMPONENTS OF THE BRAKE PAD WILL RUB
AGAINST THE BRAKE DISC, THEREBY IMPARING THE BRAKING EFFECT AND
DESTROYING THE BRAKE DISC.

Replacing the front brake pads *

Remove the front wheel (see front wheel chapter).
Press brake shoes apart with a suitable screwdriver to put the brake pistons
in their basic position.
Remove the lock washer [4] from the screw as well as fixing screw [5] and
take the brake shoes out of the brake caliper. Clean brake caliper thoroughly
with compressed air.

Mount the right brake shoe and fix with screw. Mount the left brake shoe and
tighten the screw to 4 Nm. Mount the lock washer. Align brake shoes, mount
front wheel (see chapter: Mounting the front wheel).

– IT IS VERY IMPORTANT TO KEEP THE BRAKE DISK FREE FROM OIL AND FATTY

MATTERS. OTHERWISE, THE BRAKING EFFECT WOULD BE STRONGLY REDUCED.
– AFTER ASSEMBLY, CHECK IF CIRCLIPS HAVE BEEN FITTED CORRECTLY.
– DO NOT UNSCREW ANY OTHER SCREWS ON THE BRAKE CALIPER OR YOU WILL

HAVE TO BLEED THE BRAKE SYSTEM.
– AFTER WORKING ON THE BRAKE SYSTEM ALWAYS OPERATE THE HAND BRAKE

LEVER TO APPLY THE BRAKE PADS TO THE BRAKE DISK AND CREATE A POINT

OF PRESSURE.

1

2

3

4

5

min.

1 mm

5 mm

ENGLISH

23

MAINTENANCE WORK ON CHASSIS AND ENGINE »

Changing the basic position of the foot brake lever (Junior LC)

The basic position of the foot brake lever can be changed by unscrewing screw
[1] and then turning the retainer [2].
Afterwards, check the setting of the rear wheel brake.

Adjusting the control cable on the rear wheel (Junior LC)

You should be able to press the foot brake lever 5 to 10 mm (0.2-0.4 in)
before the rear wheel begins to brake.
The brake control cable is adjusted with adjusting screw [3] on the brake anchor
cover. First loosen lock nut [4] and then tighten again.

AFTER MAKING ADJUSTMENTS, ALWAYS MAKE SURE THE WHEEL TURNS FREELY.

Drum brake maintenance (Junior LC)

Drum brake maintenance is limited to occasional blowing out of the brake
drum and brake shoes. Brake drum and brake linings can be slightly
roughened with an abrasive tape.

Changing the basic position of the foot brake lever (SeniorLC)

The basic setting of the foot brake pedal can be changed by turning the end
stop roller [5]. Using the push rod [6], the free play on the foot brake pedal
must be set.
Measured on the outside, the foot brake pedal must have 3-5 mm of free play,
before the push rod can move the piston in the brake cylinder (to be recog­nised from the resistance on the foot brake pedal)

Checking the rear brake linings for wear (Junior LC)

The brake linings must be replaced when the distance between the hub brake
lever and the cable support, measured with the brake lever squeezed, is less
than 50 mm (2 in) (see illustration).

IF THE BRAKE LININGS ARE REPLACED TOO LATE, I.E. WHEN THE LINING IS PARTLY
OR FULLY WORN AWAY, THE METAL SHOES WILL RUB AGAINST THE BRAKE DRUM,
THUS REDUCING THE BRAKING EFFECT AND DESTROYING THE BRAKE DRUM.

min 50 mm

3-5 mm

3

4

6

5

5-10 mm

2

1

2

Checking the rear brake fluid level (Senior LC)

The reservoir for the rear disk brake is on the right side of the motorcycle on
the rear brake cylinder.
No air bubble should be visible in inspection glass [A] when the vehicle is
parked in a vertical position.

IF THE BRAKE FLUID LEVEL DROPS BELOW THE UPPER EDGE OF THE INSPEC­TION GLASS, THIS INDICATES THAT THE BRAKE SYSTEM IS EITHER LEAKING OR
THE BRAKE SHOES COMPLETELY WORN.

A

Slide new brake shoes into the brake caliper a fasten with the screw [2].
Tighten the screw to 10 Nm and mount the locking screw [1].
Mount the rear wheel and actuate the foot brake lever until you can feel the
pressure point.

– IT IS VERY IMPORTANT TO KEEP THE BRAKE DISK FREE FROM OIL AND FATTY

MATTERS. OTHERWISE, THE BRAKING EFFECT WOULD BE STRONGLY REDUCED.
– AFTER ASSEMBLY, CHECK IF CIRCLIPS HAVE BEEN FITTED CORRECTLY.
– AFTER WORKING ON THE BRAKING SYSTEM, ONE MUST ALWAYS ACTUATE THE

HAND BRAKE LEVER OR FOOT BRAKE LEVER, RESPECTIVELY SO AS TO ENSURE

THAT THE BRAKE PADS WILL LIE AGAINST THE BRAKE DISK AND THE

PRESSURE POINT IS ESTABLISHED.

ENGLISH

24

MAINTENANCE WORK ON CHASSIS AND ENGINE »

1

2

min.

1 mm

Refilling the rear brake fluid reservoir * (Senior LC)

Remove the screws [1] and take off the cover [2] and diaphragm [3].The brake
pistons must be pushed back to their basic position. Fill DOT 5.1 brake fluid
(e.g. Motorex Brake Fluid DOT 5.1) up to 8 mm under the upper edge of the
reservoir.
Remount the diaphragm, cover and screws and actuate the foot brake lever
until you feel the point of pressure again. Wipe any overflowing or spilled brake
fluid off with water.

– ACTUATE THE FOOT BRAKE LEVER UNTIL YOU FEEL THE POINT OF PRESSURE

AGAIN.
– NEVER USE DOT5 BRAKE FLUID! IT IS BASED ON SILICONE OIL AND OF A

PURPLE COLOR. SEALS AND BRAKE HOSES MUST BE ESPECIALLY ADAPTED

TO IT.
– STORE BRAKE FLUID OUT OF REACH OF CHILDREN.
– BRAKE FLUID CAN CAUSE SKIN IRRITATION. AVOID CONTACT WITH SKIN AND

EYES. IF YOU GET BRAKE FLUID IN YOUR EYES, RINSE WITH PLENTY OF WATER

AND CONSULT A DOCTOR.

– DON’T LET BRAKE FLUID GET IN CONTACT WITH PAINT, IT IS AN EFFECTIVE

PAINT REMOVER.
– USE ONLY CLEAN BRAKE FLUID TAKEN FROM A TIGHTLY SEALED CONTAINER.

Refilling the rear brake fluid reservoir * (Senior LC)

Remove the screws 1 and take off the cover 2 and diaphragm 3.The brake
pistons must be pushed back to their basic position. Fill DOT 5.1 brake fluid
(e.g. Motorex Brake Fluid DOT 5.1) up to 8 mm under the upper edge of the
reservoir.
Remount the diaphragm, cover and screws and actuate the foot brake lever
until you feel the point of pressure again. Wipe any overflowing or spilled brake
fluid off with water.

– ACTUATE THE FOOT BRAKE LEVER UNTIL YOU FEEL THE POINT OF PRESSURE

AGAIN.
– NEVER USE DOT5 BRAKE FLUID! IT IS BASED ON SILICONE OIL AND OF A

PURPLE COLOR. SEALS AND BRAKE HOSES MUST BE ESPECIALLY ADAPTED

TO IT.
– STORE BRAKE FLUID OUT OF REACH OF CHILDREN.
– BRAKE FLUID CAN CAUSE SKIN IRRITATION. AVOID CONTACT WITH SKIN AND

EYES. IF YOU GET BRAKE FLUID IN YOUR EYES, RINSE WITH PLENTY OF WATER

AND CONSULT A DOCTOR.

– DON’T LET BRAKE FLUID GET IN CONTACT WITH PAINT, IT IS AN EFFECTIVE

PAINT REMOVER.
– USE ONLY CLEAN BRAKE FLUID TAKEN FROM A TIGHTLY SEALED CONTAINER.

Replacing the rear brake pads * (Senior LC)

Dismount the rear wheel (see "Dismounting the rear wheel").
Press the brake shoes apart with a suitable screwdriver to allow the brake
pistons to return to their basic position.

Remove the locking screw [1], unscrew the screw [2] and pull the brake shoes
out of the brake caliper.

1

2

3

MAINTENANCE WORK ON CHASSIS AND ENGINE »

ENGLISH

25

Removing and mounting the front wheel

Jack the motorcycle up by the frame so that the front wheel is suspended
above the ground.
Undo the hexagon nut [1] and remove it together with the washer.
Hold the front wheel and pull out the wheel spindle [2].
Carefully take the front wheel out of the fork.

– DO NOT OPERATE THE HAND BRAKE WHEN THE FRONT WHEEL HAS BEEN

DISMOUNTED.
– MAKE SURE THE BRAKE DISC IS ALWAYS ON TOP WHEN YOU LAY DOWN THE

WHEEL, OTHERWISE THE BRAKE DISC CAN BE DAMAGED.

Lift the front wheel into the fork and correctly position it.
Mount the wheel spindle [2].
Mount the washer and the hexagon nut [1] and tighten 40 Nm.
Put the motorcycle back on the ground and operate the front wheel brake until
the working point is reached.

– 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.
– AFTER MOUNTING THE FRONT WHEEL, KEEP OPERATING THE HAND BRAKE

UNTIL THE PRESSURE POINT RETURNS.
– IT IS VERY IMPORTANT TO KEEP THE BRAKE DISK FREE FROM OIL AND FATTY

MATTERS, EITHERWISE THE BRAKING EFFECTS WOULD BE STRONGLY REDUCED.

Removing and mounting the rear wheel

Prop up the motorcycle under the frame.
Remove hexagon nut [3] on the wheel spindle and disk.
Hold the rear wheel and remove the wheel spindle.
Move the rear wheel forwards, remove chain, lift the rear wheel out of the
swinging fork and remove the brake anchor.

– DO NOT OPERATE THE REAR BRAKE WHEN THE REAR WHEEL HAS BEEN

DISMOUNTED.
– MAKE SURE THE BRAKE DISC IS ALWAYS ON TOP WHEN YOU LAY DOWN THE

WHEEL, OTHERWISE THE BRAKE DISC CAN BE DAMAGED.(SENIOR LC)

To mount the wheel reverse the procedure described above.
Always hook the brake backing plate into the swing arm support.
Before tightening the hexagon nut of the wheel spindle, ensure that the
supporting plates [4] are resting against the swing arm. Additionally, check
that the rear wheel is aligned with the front wheel.
Tighten the hexagon nut to 40 Nm.

– 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.
– AFTER MOUNTING THE REAR WHEEL, KEEP OPERATING THE REAR BRAKE UNTIL

THE PRESSURE POINT RETURNS.(SNIOR LC)
– IT IS VERY IMPORTANT TO KEEP THE BRAKE DISK FREE FROM OIL AND FATTY

MATTERS, OTHERWISE THE BRAKING EFFECTS WOULD BE STRONGLY

REDUCED.(SENIOR LC)

4

3

4

2

1

MAINTENANCE WORK ON CHASSIS AND ENGINE »

ENGLISH

26

Tires, air pressure

Tire type, tire condition, and air pressure level affect the way your motorcycle
rides, and they must therefore be checked whenever you are getting ready to
go anywhere on your motorcycle.
– Tire size can be found in the technical specifications.
– Tire condition has to be checked every time you want to ride your motor-

cycle. Before leaving, check tires for punctures and nails or other sharp
objects that might have become embedded in them.

– Regularly check the "cold" tire pressure. Correct tire pressure (1.0 bar /

14 psi) guarantees optimum grip and maximum tire life.

– DAMAGED TIRES MUST BE REPLACED IMMEDIATELY TO PROTECT YOUR

YOUNGSTER.
– WORN TIRES CAN HAVE A NEGATIVE EFFECT ON HOW THE MOTORCYCLE

PERFORMS, ESPECIALLY ON WET SURFACES
– TIRE PRESSURE BELOW THE NORMAL LEVEL WILL LEAD TO PREMATURE TIRE

WEAR.

Checking spoke tension

The correct spoke tension is very important for the stability of the wheels and
thus for riding safety. A loose spoke causes the wheel to become
unbalanced and before long other spokes will have come loose. 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.
– EXCESSIVELY TENSIONED SPOKES MAY RUPTURE DUE TO LOCAL OVERLOAD-

ING. THE SPOKES MUST BE TENSIONED TO 3 NM.

Cooling system

The water pump [1] in the engine keeps the cooling liquid in circulation.
The cooling liquid is cooled by the air stream. Therefore, the cooling effect
is reduced when the traveling speed is reduced. Dirty radiators additionally
reduce the cooling effect.

The cooling liquid can be drained by removing screw [2] on the water-pump
cover.

DO NOT REMOVE ANY COOLER HOSES OR THE DRAIN SCREW WHEN THE ENGINE
IS HOT.

A mixture of 50% antifreeze liquid and 50% water is used as coolant.
How-ever, the antifreeze protection must be at least -25° C (-13° F). This mix­ture offers antifreeze protection but also good corrosion protection and should
therefore not be replaced by pure water.

FOR THE COOLING SYSTEM, USE ONLY WITH HIGH-GRADE ANTIFREEZE (MOTOREX
ANTI-FREEZE). USING LOWER-GRADE ANTIFREEZE AGENTS CAN CAUSE CORRO­SION AND COOLANT FOAMING.

Pressure induced by heating of the coolant in the system is controlled by
a valve in the radiator cap [

3]

; a water temperature rising up to 120° C

(248° F) is admissible without fear of problems.

1

2

3

MAINTENANCE WORK ON CHASSIS AND ENGINE »

ENGLISH

27

Checking coolant level

The coolant should be 10 mm (0.4 in) above the radiator fins when the engine
is cold (see illustr.). In the event of the coolant being drained, always fill and
bleed the system.

IF POSSIBLE, ALWAYS CHECK LEVEL OF COOLING LIQUID WHEN ENGINE IS COLD.
IF YOU HAVE TO OPEN THE RADIATOR CAP WHEN THE ENGINE IS HOT, USE A RAG
TO COVER THE CAP AND OPEN SLOWLY TO RELEASE PRESSURE.

Cleaning the air filter *

The air filter must be cleaned at intervals depending on the amount of dust
accumulated. To clean the air filter, first remove the seat. Then press both
retaining clips [1], remove the filter holder and the air filter [2]. The air
filter consists of a foam rubber insert soaked with filter oil.

– DO NOT CLEAN THE FOAM FILTER WITH FUEL OR PETROLEUM SINCE THESE

WILL DAMAGE THE FOAM. KTM RECOMMENDS THE PRODUCTS (MOTOREX LIQUID

BIO POWER) FOR AIR FILTER MAINTENANCE.
– NEVER OPERATE YOUR MOTORCYCLE WITHOUT AN AIR FILTER. OTHERWISE,

DUST AND DIRT MAY GET INTO THE ENGINE AND LEAD TO INCREASED WEAR.
– THE HOLDER MUST RETAIN THE AIR FILTER THROUGHOUT ITS ENTIRE CIR-

CUMFERENCE. IF THE FILTER HAS BEEN MOUNTED INCORRECTLY, THE ENGINE

WILL TAKE IN UNFILTERED AIR, THEREBY CAUSING INCREASED ENGINE

WEAR.

Thoroughly wash the foam filter in special cleaning fluid (Motorex Bio Dirt
Remover) and allow it to dry well. Only press out the filter, do not wring it out
under any circumstances. Oil the dry foam filter with a high-grade filter
oil ( Motorex Liquid Bio Power). Also clean the air filter box. Check carbure­tor collar for damage and that it is filled correctly.
Insert the air filter in the opening and fasten it with the filter holder. Then
mount the seat.

Exhaust system *

The silencer is filled with glass-fiber yarn for damping. When in use, the glass­fiber yarn becomes loose or coked with oil carbon. This can lead to a power
loss and a reduction of the silencer damping. The glass-fiber yarn packing
can be replaced in a few easy steps.
To replace, remove the silencer from the vehicle and mark the position of the
outer tube [3] to the inner tube [4]. Remove screws [5] and the end cap [6].
Pull of the outer tube and remove the old glass-fiber yarn packing [7] from
the inner tube. Thoroughly clean all parts.

To assemble, mount a new glass-fiber yarn packing onto the inner tube (see
illustration) and slide into the outer tube. Mount end cap and fix with
screws [5]. Before tightening the screws, turn the outer tube until they match
the positions you marked. 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.

1

1

2

7

5

6

3

4

when engine is cold

10 mm

MAINTENANCE WORK ON CHASSIS AND ENGINE »

ENGLISH

28

Changing the seat height

The saddle can easily be raised by 25 mm (1 in). This lets you adjust the
height as your child grows.

Figures A and B show the fork and shock absorber positions for a low seat
position. The fork tubes extend approx. 17 mm (0.7 in) (H) above the upper
fork stabilizer. The shock absorber is attached to the upper hole in the frame.
Tighten the clamp screws on the fork stabilizers to 20 Nm (top) and
15 Nm (bottom), the screw on the shock absorber to 45 Nm.

Figures A and B: low seat position
Figures C and D: high seat position

Figures C and D show the fork and shock absorber positions for a high seat
position.Fork tubes are plane with top of upper fork stabilizer. (Screw cap
(Aluminium) protrudes from the top of the upper fork stabilizer)
The shock absorber is attached to the lower hole in the frame. Tighten the
clamp screws on the fork stabilizers to 20 Nm (top) and 15 Nm (bottom), the
screw on the shock absorber to 45 Nm.

THE FORK TUBES MAY NOT BE LOWERED ANY FURTHER THAN AS DESCRIBED
ABOVE, OTHERWISE THE CLAMPING ON THE UPPER FORK STABILIZER WILL NO
LONGER BE ADEQUATE.

Adjusting the throttle cable *

There must always be a 3 to 5 mm (0.1 to 0.2 in) play in the throttle cable.
To check this, move back the protective cover [1] on the throttle grip. You
must be able to lift the outer covering of the cable 3-5 mm from the adjust­ing screw [2], until resistance is felt.
To adjust, loosen the counter nut [3] and turn the adjusting screw accord­ingly. Finally tighten counter nut and slide the protective cover back on.

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

The idle speed can be adjusted with screw [4].

The idle speed is increased by turning clockwise.
The idle speed is reduced by turning counter-clockwise.

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

The idle speed can be adjusted with screw [5].

The idle speed is increased by turning clockwise.
The idle speed is reduced by turning counter-clockwise.

C D

4

5

H

BA

3-5 mm

3

1

2

MAINTENANCE WORK ON CHASSIS AND ENGINE »

ENGLISH

29

Checking the gear oil level

To check the gear oil level, first remove the plug [1]. With the motorcycle parked
in an upright position, a small quantity of oil should flow out of the indicator
opening [2]. If oil must be added, tilt the motorcycle and pour automatic gear
oil (Motorex ATF Super) into the bore.

LESS OIL OR A POOR OIL QUALITY LEAD TO PREMATURE TRANSMISSION WEAR.
THEREFORE, ONLY USE BRANDED PRODUCTS (MOTOREX ATF SUPER).

Changing gear oil *

The engine must be warmed up before changing the gear oil. Park the motor­cycle on a horizontal surface, remove the oil drain plug [3] and drain the used
oil into an appropriate container. Clean the sealing surface, mount the oil drain
plug together with the gasket and tighten to 15 Nm.

Remove stopper [4] and fill in 0.15 liters of automatic gear oil (Motorex ATF
Super). Mount the stopper and check the engine for tightness.

LESS OIL OR A POOR OIL QUALITY LEAD TO PREMATURE TRANSMISSION WEAR.
THEREFORE, ONLY USE BRANDED PRODUCTS (MOTOREX ATF SUPER).

2

1

3

4

TROUBLE SHOOTING »

ENGLISH

30

If you let the specified maintenance work on your motorcycle be carried out, disturbances can hardly be expected. Should an error
occur nevertheless, we advise you to use the trouble shooting chart in order to find the cause of error.
We would like to point out that many operations cannot be performed by oneself. In case of uncertainty, please contact a KTM-dealer.

TROUBLE CAUSE REMEDY

Engine fails to start Operating error

Fuel supply interrupted

Electrode distance too large

Plug fouled by oil, wet or bridged

Ignition wire or spark plug connector
damaged

Kill button wire or
short-circuit switch faulty

Loose ignition cable connectors

Spark too weak

Water in the carburetor and jets
blocked

Open fuel tap, replenish fuel, do not use choke

Close fuel tap, loosen fuel hose at carburettor, lead into a
basin and open fuel tap,
– if fuel leaks out, clean carburettor
–

if no fuel leaks out, check tank ventilation, i.e. clean fuel
tap

Reduce electrode distance (0.60 mm)

Clean spark plug or renew

Dismount spark plug, connect ignition cable, hold to
ground (blank place on engine) and actuate kickstarter, a
strong spark must be produced at the spark plug
–

If no spark is produced, loosen spark plug cap from igni­tion cable, hold about 5 mm from ground and actuate

kickstarter
– If a spark now occurs, replace spark plug cap
– If no spark is produced, control ignition system

Disconnect black coloured cable from short circuit button
at ignition coil and check ignition spark. If the spark is
O.K. repair defective part of cable or ignition switch

Inspect cable connectors

Examine ignition system

Dismantle and clean carburetor

Engine without idle running

Idle adjusting screw out of adjustment

Ignition system damaged

Wear

Readjust idle running or replace idle adjusting screw

Examine ignition system

Overhaul engine

Less power of engine Air filter obstructed

Fuel supply partly interrupted or
blocked

Loss of compression due to loose
spark plug

Exhaust system damaged

Engine has not enough preignition

Reed paddles tensionless or dama­ged, surface of reed valve housing
damaged

Wear

Clean or renew airfilter

Blow through fuel pipe and clean carburetor

Tighten spark plug

Check exhaust system for damage

Check and adjust ignition

Replace reed paddles or reed valve housing

Overhaul engine

TROUBLE SHOOTING »

ENGLISH

31

TROUBLE CAUSE REMEDY

Engine stalling or running with
four stroke cycle

Carburetor overflows if level adjust
too high, float needle seating is dirty
or enlarged

Loose carburetor jets

Clean carburetor, if necessary replace float needle and
adjust level

Tighten jets

High rpm misfiring Incorrect heat range spark plug or

low quality spark plug

Loose, corroded or non conductive
ignition socket connector

Refer to technical data section

Check and seal with silicon

Engine spluters into the carburetor

Lack of fuel

Spark plug with incorrect heat value
(Ignition by incandescence)

Engine takes air out of control

Clean fuel pipes, examine tank aeration and clean

Fit correct spark plug

Check intake flange and carburettor if firmly setted

Engine overheating Insufficient liquid in cooling system

Radiator fins clogged

Frothing in cooling system

Pinched or kinked water hoses

Incorrect ignition timing because of
loose stator screws

Incorrect compression ratio

Top up coolant and bleed cooling system check cooling
system for leaks

Clean radiatar fins with water jet

Renew coolant using branded anti-freeze/anti-corrosive
(Motorex Anti-Freeze)

Replace with correct routed hoses

Readjust to correct ignition timing specifications, secure
screws with Loctite 243

Measure and adjust compression ratio

Emission of white smoke
(steam)

Cylinder head or O-ring of cylinder
head gasket leaks

Check cylinder head, replace O-ring

Excessive oil escapes from
transmission breather tube

Excessive oil quantity in transmission Correct transmission oil level

STORAGE »

CLEANING »

ENGLISH

32

If you want to put your motorcycle away for longer periods of time, please observe the following instructions:

– Clean motorcycle thoroughly (see chapter: CLEANING)
– Change engine oil (old engine oil contains aggressive contaminations).
– Check antifreeze and amount of cooling liquid.
– the engine warm up again, close fuel tap and wait until the engine dies off by itself. In this way, the carburetor jets are preven-

ted from becoming resin-clogged by the old fuel.

– Remove spark plug and fill in approx. 5 ccm of engine oil into the cylinder through the opening. Actuate kickstarter 10 times in

order to distribute the oil onto the cylinder walls and mount the spark plug.
– Let fuel flow out of tank into an appropriate basin.
– Correct tire pressure.
– Lubricate bearing points of the control levers, footrests, etc. as well as the chain.
– The storage place should be dry and not be subjected to overly great temperature fluctuations.
– Cover the motorcycle with an air permeable tarpaulin or blanket. Do not use airtight materials, as possible humidity might not be

able to escape and thereby cause corrosion.

IT WOULD BE VERY BAD TO LET THE ENGINE RUN FOR A SHORT TIME DURING THE STORAGE PERIOD. THE ENGINE WOULD NOT GET WARMED
UP ENOUGH AND THE THUS DEVELOPED STEAM WOULD CONDENSE DURING THE COMBUSTION PROCESS AND CAUSE THE EXHAUST TO
RUST.

USE AFTER PERIOD OF STORAGE

– Fill up tank with fresh fuel.
– Check motorcycle as before each start (see driving instructions).
– Take a short, careful test ride first.

NOTE: Before you put your motorcycle away for the winter, you should check all parts for their function and wear. Should any service
jobs, repairs, or any refitting be necessary, you should have them carried out during the off-season (lower workload at mechanics'
shops). This way, you can avoid the long waiting times at your shop at the beginning of the next biking season.

Clean your motorcycle regularly in order to keep its painted finish looking shiny and new.
The best manner would be to use warm water that has been mixed with a commercially available washing detergent and a sponge. The
hard dirt can be removed before with the help of a soft water jet.

NEVER CLEAN YOUR MOTORCYCLE WITH A HIGH-PRESSURED CLEANER OR A HIGH-PRESSURED WATER JET, OTHERWISE THE WATER MIGHT
RUN INTO THE ELECTRICAL COMPONENTS, CONNECTORS, SHEATHED CABLES, BEARINGS, CARBURETOR ETC. AND CAUSE MAILFUNCTIONS,
I.E., LEAD TO THE PREMATURE DESTRUCTION OF THESE PARTS.

– You should use commercially available detergents to clean the motorcycle. Heavily soiled parts should also be cleaned with the

help of a paint brush.
– 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. The heat also causes the water at the inac-

cessible parts of the engine and the brakes to evaporate.
– Slide back the protective covers on the handlebar-mounted instruments so that any water that may have seeped into this part of

the motorcycle is allowed to evaporate.
– After the motorcycle has cooled down, oil and grease all the gliding bearing parts. Also treat the chain with a chain spray.
– To prevent failures in the electric system, you should treat the short circuit button with a contact spray.

TECHNICAL DATA – ENGINE »

ENGLISH

33

TYP 50 SX PRO JUNIOR LC 50 SX PRO SENIOR LC

Design single cylinder 2-stroke engine, with reed valve inlet
Displacement 49.0 ccm
Bore/Stroke 39.5 / 40 mm
Fuel SUPER fuel, research octane no 95, mixed with 2-stroke oil

Oil/gasoline ratio

1 : 40 when using high grade 2-stroke oil (Motorex 2T Cross Power)
When in doubt, please contact your importer or use 1 : 33 mix ratio to be on the safe side

Lubrication mixture lubrication
Crankshaft bearing 2 grooved ball bearing
Connecting rod bearing needle bearing
Piston pin bearing needle bearing
Piston rings 1 rectangular ring
Primary drive straight cut spur gears, 16 : 57 Z
Transmission oil 0.15-0,2 liter automatic gear oil Dexron II (Motorex Topspeed 4T 15W50)
Spark plug NGK BR 8 ECM
Electrode gap 0.6 mm
Carburetor DellOrto PHVA 14 DS Dell’Orto PHBG 19 BS
Air filter wet foam type air filter insert
Cooling liquid 0.5 litres, 50% antifreeze, 50% water, at least -25 °C (-13 °F)

BASIC CARBURETOR SETTING

Model 50 SX PRO JUNIOR LC 50 SX PRO SENIOR LC

Type Dell’Orto PHVA 14 DS Dell’Orto PHBG 19 BS
Main jet 80 85
Needle jet 211 FA 260 AU
Idling jet 45 48
Jet needle A10 W9
Needle position from top 3. 3.
Air/Mixture reg. screw open 3.5 3.0
Slide 40 60
Starting jet 60 60

TIGHTENING TORQUES - ENGINE

Primary gear nut M14x1,25 40 Nm
Hexagon nut ignition rotor M10x1,25 20 Nm
Nut of clutch hub M10x1,25 Loctite 243 + 35 Nm
Cylinder head screws M7 15 Nm
Cylinder base nuts M8 18 Nm
Allan head screw-Stator M5x25 Loctite 243 + 8 Nm
Oil plug M16 5 Nm
Oil drain plug M10 15 Nm

Other engine screws

M5
M6
M8

7 Nm
10 Nm
30 Nm

TECHNICAL SPECIFICATIONS - CHASSIS »

ENGLISH

34

50 SX PRO JUNIOR LC 50 SX PRO SENIOR LC

Frame single downtube, split-cradle
Fork Marzocchi Ø = 32 mm (1.26 in)
Wheel travel front/rear 140/205 mm (5.5/8 in) 185/185 mm (7.3/7.3 in)
Rear suspension Central shock absorber WP
Front brake Disk brake Ø 160 mm (6.4 in)
Rear brake Drum brake Ø 90 mm (3.5 in) Disk brake Ø 140 mm (5.5 in)
Tires front/rear 2.50x10” Pirelli MT32A / 2.75x10” MT320 2.50x12” Pirelli MT32A / 2.75x10” MT320
Tire pressure front/rear: 1.0 bar
Fuel tank capacity 1.8 Liters
Final drive ratio 11 : 48 10 : 44
Chain 1/2x3/16“ 96 rolls 1/2x3/16“ 102 rolls
Steering angle 66° 66°
Wheel base 910 mm (35.8 in) 1030 mm (40 in)
Seat height, unloaded 585 mm/610 mm (23/24 in) 650/675 mm (25.6/26.6 in)
Ground clearance 220 mm (8.6 in) 255 mm (10 in)
Rider’s body height max. 130 cm (51 in)
Rider’s body weight max. 35 kg (78 lbs)
Recommended age of rider 4-7 years 6-10 years
Engine 50 LC

TIGHTENING TORQUES

Hexagon nuts front/rear axle M12x1 40 Nm
Hexagon nut swing arm bolt M12 40 Nm
Clamping screw upper fork bridge M8 20 Nm
Clamping screw lower fork bridge M8 15 Nm
Screws handlebar clamp M8 20 Nm
Shock absorber top/bottom M10 45 Nm
Allan screw – Handlebar support M10 Loctite + 40 Nm
Front brake caliper M8 Loctite + 20 Nm
Front brake disk M6 Loctite + 10 Nm
Swing arm bolt M12x1 40 Nm
Spoke nipple M4 3 Nm

Other chassis screws

M5
M6
M8
M10

6 Nm
10 Nm
25 Nm
45 Nm

STANDARD-ADJUSTMENT – FORK

Spring 2.0 N/mm
Preload 10 mm (0.4 in)
Fork oil SAE 7.5
Air chamber length 110 mm (4.3 in)

STANDARD ADJUSTMENT - SHOCK ABSORBER

JUNIOR LC

WP 03189A01

SENIOR LC

WP 03189A02

Rebound adjuster 5 5
Spring 85 N/mm 45 N/mm
Spring preload 10 mm (0.39 in) 7 mm (0.28 in)

HEAD WORD INDEX »

ENGLISH

35

Page

Adjusting the control cable on the rear wheel (Junior LC)

23

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

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

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

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

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

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

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

Changing spring preloading of the shock absorber . . .20

Changing the basic position of the foot brake lever

(Junior LC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Changing the basic position of the foot brake lever

(SeniorLC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

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

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

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

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

Checking and adjusting the steering head bearing

(JUNIOR LC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Checking and adjusting the steering head bearing

(SENIOR LC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17

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

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

Checking rear brake pads (Senior LC) . . . . . . . . . . . .24

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

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

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

Checking the rear brake fluid level (Senior LC) . . . . .23

Checking the rear brake linings for wear (Junior LC) . .23

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

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

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

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

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

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

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

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

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

Drum brake maintenance (Junior LC) . . . . . . . . . . . .23

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

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

Page

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

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

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

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

General Tips and Warnings for starting the motorcycle .10

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

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

Important Information for parents about safe driving . . .4

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

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

Maintenance work on chassis and engine . . . . . . . . . .16

Operation instruments . . . . . . . . . . . . . . . . . . . . . . . .7

Periodic maintenance schedule . . . . . . . . . . . . . . . .14

Plugin - Stand (SENIOR LC) . . . . . . . . . . . . . . . . . . .9

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

Refilling the rear brake fluid reservoir (Senior LC) . . .24

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

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

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

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

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

Replacing the rear brake pads (Senior LC) . . . . . . . .24

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

Serial number locations . . . . . . . . . . . . . . . . . . . . . . .6

Setting the basic position and play of the hand brake lever

21

Short circuit button . . . . . . . . . . . . . . . . . . . . . . . . .6

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

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

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

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

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

Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Technical data – engine . . . . . . . . . . . . . . . . . . . . . .33

Technical specifications - chassis . . . . . . . . . . . . . . .34

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

Throttle grip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

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

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

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

Trouble shooting . . . . . . . . . . . . . . . . . . . . . . . . . . .30

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

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

ENGLISH

36

KTM-Sportmotorcycle AG

A–5230 Mattighofen

www.ktm.at

KTM Group Partner