KTM 50 SX PRO JUNIOR LC 2004 User manual

OWNER`S MANUAL
MANUALE D`USO
MANUEL D`UTILISATION
MANUAL DE INSTRUCCIONES
ART.NR: 3.210.73
50 SX PRO JUNIOR LC
50 SX PRO SENIOR LC
BEDIENUNGSANLEITUNG2004

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1
Please insert the serial numbers of the motorcycle below
Chassis number
Engine number
Stamp of dealer
IMPORTANT
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 PARTI-
CULAR ATTENTION TO INSTRUCTIONS AND INFORMATION MARKED AS
FOLLOWS:
 WARNING 
IGNORING THESE INSTRUCTIONS CAN BE DANGEROUS TO LIFE
AND LIMB.
! CAUTION !
IGNORING THESE INSTRUCTIONS MAY DAMAGE PARTS OF THE
MOTORCYCLE OR IMPAIR THE MOTORCYCLE’S TRAFFIC
SAFETY.
KTM-S PORTMOTORCYCLE AG RESERVES THE RIGHT TO MODIFY ANY EQUIPMENT , TECHNICAL SPECIFICATIONS , COLORS ,
MATERIALS , SERVICES OFFERED AND RENDERED , AND THE LIKE SO AS TO ADAPT THEM TO LOCAL CONDITIONS WITHOUT
PRIOR NOTICE ANNOUNCEMENT AND WITHOUT GIVING REASONS
, OR TO CANCEL ANY OF THE ABOVE ITEMS WITHOUT
SUBSTITUTING THEM WITH OTHERS
. I TSHALL BE ACCEPTABLE TO STOP MANUFACTURING A CERTAIN MODEL WITHOUT PRE -
VIOUS ANNOUNCEMENT . I NTHE EVENT OF SUCH MODIFICATIONS , PLEASE ASK YOUR LOCAL KTM DEALER FOR INFORMA -
TION .

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2
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 motorcy-
cle 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 motorcy-
cle 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
ALL RIGHTS RESERVED TO MAKE ALTERATIONS TO DESIGN AND MODEL.
©by KTM-SPORTMOTORCYCLE AG, AUSTRIA All rights reserved

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3
IMPORTANT WARRANTY AND
GUARANTEE INFORMATIONE
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 fault-
less 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 compo-
nents such as the drive train or the brakes. In this case it may become neces-
sary 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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4
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 mainenance
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 supervising
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 conditions 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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Page
IMPORTANT INFORMATION FOR PARENTS ABOUT SAFE
DRIVING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
SERIAL NUMBER LOCATIONS . . . . . . . . . . . . . . . . . . . . . . . .6
Chassis number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Engine number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Engine typ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
OPERATION INSTRUMENTS . . . . . . . . . . . . . . . . . . . . . . . . . .6
Throttle grip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Hand brake lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Short circuit button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Filler cap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Fuel tap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Choke (Dell’Orto carburetor PHVA 14 DS) . . . . . . . . . . . .7
Choke (Dell’Orto carburetor PHBG 19 BS) . . . . . . . . . . . . .7
Kickstarter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Foot brake lever . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Side stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Plugin - Stand (SENIOR LC) . . . . . . . . . . . . . . . . . . . . . . . .8
Rebound damping function of the shock absorber . . . . . . .8
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 2004 . . . . . . . . . . . .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
TABLE OF CONTENTS
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) . . . . . . . . .24
Refilling the rear brake fluid reservoir (Senior LC) . . . . . . .24
Checking rear brake pads (Senior LC) . . . . . . . . . . . . . . .25
Replacing the rear brake pads (Senior LC) . . . . . . . . . . . .25
Removing and mounting the front wheel . . . . . . . . . . . . .26
Removing and mounting the rear wheel . . . . . . . . . . . . .26
Tires, air pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Checking spoke tension . . . . . . . . . . . . . . . . . . . . . . . . . .27
Cooling system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Checking coolant level . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Cleaning the air filter . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Exhaust system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Changing the seat height . . . . . . . . . . . . . . . . . . . . . . . . .29
Adjusting the throttle cable . . . . . . . . . . . . . . . . . . . . . . .29
Adjusting the idle speed (Dell’Orto PHVA 14 DS) . . . . . .29
Adjusting the idle speed (Dell’Orto PHBG 19 BS) . . . . . . .29
Checking the gear oil level . . . . . . . . . . . . . . . . . . . . . . . .30
Changing gear oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30
TROUBLE SHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
CLEANING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
TECHNICAL DATA – ENGINE 50 LC 2004 . . . . . . . . . . . . . .34
TECHNICAL SPECIFICATIONS - CHASSIS 50 LC 2004 . . . . . . .35
HEAD WORD INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

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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.
Engine typ
50 MCH
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 1turns off the engine. When pressing this button,
the ignition circuit is short-circuited.
SERIAL NUMBER LOCATIONS
OPERATION INSTRUMENTS
1

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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 1without kinks.
Fuel tap
The fuel tap 2is 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.
Choke (Dell’Orto carburetor PHVA 14 DS)
Choke lever 3is 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 4is 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.
NOTE: an accessory kit for kickstarter backwards operation is available.
1
2
3
4

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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.
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
 WARNING 
–NEVER TURN THE SETTING WHEEL MORE THAN TWO CLICKS BETWEEN TWO TEST
RIDES.
–D
ONOT TRY TO DISASSEMBLE THE SHOCK ABSORBER OR TO PERFORM MAINTE-
NANCE WORK YOURSELF. DANGER OF INJURY!
1
2

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10
GENERAL TIPS AND WARNINGS FOR STARTING THE MOTORCYCLE
 WARNING 
–H
AVE 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!
–T
HE MOTORCYCLE HAS A CENTRIFUGAL CLUTCH. THE MOTORCYCLE
BEGINS TO MOVE AS SOON AS THE THROTTLE IS OPENED.
–
A
LWAYS APPLY THE FRONT BRAKE WHEN STARTING THE ENGINE AND
RELEASE THE BRAKE SLOWLY WHEN THE ENGINE IS RUNNING
. A N
ACTIVATED CHOKE INCREASES THE IDLE SPEED OF THE ENGINE
, THE CEN -
TRIFUGAL CLUTCH THUS BEGINNING TO ENGAGE
. T HEREFORE , 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.
–Y
OUR CHILD SHOULD NEVER DRIVE FASTER THAN ITS SKILLS AND THE
TERRAIN PERMIT.
–N
EVER LET YOUR CHILD DRIVE ITS MOTORCYCLE UNCHAPERONED.
–R
EPLACE THE HELMET VISOR OR GOGGLE GLASSES EARLY ENOUGH.
WHEN LIGHT SHINES DIRECTLY ON A SCRATCHED VISOR OR GOGGLES,
YOU WILL BE PRACTICALLY BLIND.
–O
NLY USE ACCESSORY PARTS RECOMMENDED BY KTM.
–NEVER LEAVE YOUR MOTORCYCLE WITHOUT SUPERVISION AS LONG AS
THE ENGINE IS RUNNING.
 WARNING 
–KTM MINI MODELS ARE DESIGNED FOR ONE PERSON ONLY. PASSEN-
GERS ARE NOT ALLOWED.
–T
HESE MODELS DO NOT COMPLY WITH THE REGULATIONS AND SAFETY
STANDARDS ESTABLISHED BY THE LAW. THEREFORE, THEY ARE NOT
PERMITTED ON PUBLIC ROADS.
–A
LWAYS 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. There-
fore, 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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11
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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12
Starting when the engine is cold
1Open fuel tap 1.
2Operate the choke 2.
3Kick the side up all the way or remove the plug-in stand.
4Apply the front brake.
5Operate the kickstarter, depressing it all the way, without opening the
throttle.
 WARNING 
– W HEN 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.
–D
ONOT 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.
! CAUTION !
DON’TRIDE 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
1Open fuel tap 1.
2Kick the side up all the way or remove the plug-in stand.
3Apply the front brake.
4Operate the kickstarter, depressing it all the way, without opening the
throttle.
What to do when the engine is “flooded”
1Close fuel tap 1.
2Applying the front brake.
3
Start engine with full throttle. If necessary, unscrew spark plug and dry
it .
4Once the engine is running, open fuel tap again.
Starting off
Slowly release the brake lever while simultaneously opening the throttle.
 WARNING 
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.
 WARNING 
–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.
2
1

ENGLISH
13
!
CAUTION
!
–DRIVING A COLD ENGINE AT HIGH SPEED WILL REDUCE THE LIFE OF
THE ENGINE. WERECOMMEND TO WARM THE ENGINE UP AT A
MEDIUM ENGINE SPEED FOR SEVERAL MINUTES BEFORE SWITCHING TO
FULL LOAD.
–N
EVER 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.
–I
NTHE EVENT THAT, WHILE YOUR CHILD IS RIDING ON THE MOTOR-
CYCLE, 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.
 WARNING 
–BRAKE DRUM AND LININGS HEAT UP DURING BRAKE OPERATION, THUS
REDUCING THE EFFECT OF THE BRAKES.
–WET BRAKES HAVE REDUCED BRAKE PERFORMANCE, THEREFORE BE
SURE TO BRAKE THEM DRY AFTER CLEANING.
–I
FTHE RESISTANCE OF THE HAND BRAKE LEVER FEELS UNRESPONSIVE,
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.
 WARNING 
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 .
!
CAUTION
!
–C
LOSE THE FUEL TAP WHEN LEAVING THE MOTORCYCLE. OTHERWISE
THE CARBURETOR MAY GET FLOODED AND FUEL WILL ENTER THE
ENGINE.
–T
HE SIDE STAND OR PLUG-IN STAND IS DESIGNED TO HOLD THE
WEIGHT OF THE MOTORCYCLE ONLY. BYSITTING ON THE MOTORCY-
CLE, 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.
 WARNING 
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. BECAREFUL NOT TO SPILL
GASOLINE ON THE ENGINE OR EXHAUST PIPE WHILE THE ENGINE IS HOT.
WIPE UP SPILLS PROMPTLY. IFGASOLINE IS SWALLOWED OR SPLASHED IN
THE EYES, SEEK A DOCTOR’SADVICE IMMEDIATELY.
! CAUTION !
–O
NLY USE PREMIUM-GRADE GASOLINE ROZ 95 MIXED WITH HIGH-
GRADE TWO-STROKE ENGINE OIL. OTHER TYPES OF GASOLINE CAN
CAUSE ENGINE FAILURE.
–O
NLY USE KNOWN BRANDS OF HIGH-GRADE 2-STROKE ENGINE OIL
(MOTOREX 2T CROSS POWER).
–N
OT ENOUGH OIL OR LOW-GRADE OIL CAN CAUSE EROSION OF THE
PISTON. WHEN
U SING 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 2004
Service
every
5 hours
Service
every
20 hours
M AINTENANCE WORK DONE BY KTM AUTHORISED WORKSHOPS IS NOT A SUBSTITUTE FOR CARE AND CHECKS DONE BY THE RIDER !
A clean motorcycle can be checked more quickly which saves money!
Check engine for leaks ●
Change transmission oil ●
Check spark plug, change it if necessary, set electrode gap ●
Check carburetor for a tight fit at intake flange ●
Check intake flange for cracks ●
Check idle setting when engine is warm ●
Check cooling system for leaks, check quantity of antifreeze ●
Check exhaust system for leaks and suspension ●
Check actuating cables for damage, smooth operation, and kinkless ●
arrangement, adjust and lubricate
Clean air filter and air filter box ●
Check brake fluid level, lining thickness, brake discs ●
Check the brake line and the brake control cable for damage ●
Check/function adjust smooth operation, free travel of handbrake/footbrake levers ●
Check screws of brake system for a tight fit ●
Check suspension strut and fork for leaks and a proper function ●
Check swinging-fork pivot ●
Check/adjust steering-head bearing ●
Check all chassis screws for a tight fit (fork plates, axle nuts, ●
swinging-fork pivot, suspension strut)
Check spoke tension and rim joint ●
Check tire condition and inflation pressure ●
Check chain, chain joint, chain wheels, chain wheel guides for wear, a tight fit, and tension ●
Lubricate chain ●
Check wheel bearings for play ●
IMPORTANT RECOMMENDED MAINTENANCE PROCEDURES TO BE PERFORMED BASED ON A SEPARATE SUPPLEMENTARY ORDER
Drain and clean the carburetor's float chamber ●
Perform complete fork maintenance ●
Clean and lubricate the swinging-arm bearing ●
Clean and lubricate the steering-head bearing and sealing elements ●
Change brake fluid ●
WHEELS CHASSIS BRAKES
ADD-ON-PARTS
ENGINE
50 SX PRO JUNIOR/SENIOR LC
water cooled
once a year
CARBURETOR

ENGLISH
15
VITAL CHECKS AND CARE PROCEDURES TO BE CONDUCTED BY THE OWNER OR THE MECHANIC
Check transmission oil level ●
Check cooling liquid level ●
Check brake fluid level ●
Check brake pads for wear ●
Check brake performance ●●
Lubricate and adjust actuating cables and nipples ●
Remove and clean dust sleeves of telescopic fork at regular intervals ●
Clean and lubricate chain, check tension and readjust it if necessary ●●
Clean air filter and filter box ●
Check tire inflation pressure and wear ●
Check fuel line for leaks ●
Drain and clean float chamber ●
Verify smooth operation of all controls ●
Treat exposed metal components (except for the brake and exhaust systems) ●
with wax-based anti-corrosion agents
Check all screws, nuts, and hose clamps for their tight fit at regular intervals ●
for cross country use
once a year
after every cleaning
before each start
RECOMMENDED INSPECTION OF THE MINI LC ENGINE BY YOUR KTM WORKSHOP
(ADDITIONAL ORDER FOR THE KTM WORKSHOP)
Check the reed-type intake valve for wear ●●●●●●
Check the clutch shoes for wear ●●●●●●
Check the clutch drum for wear ●●●●●●
Check the water pump shaft and bearings for wear ●●●●●●
Check the water pump wheel for wear ●●●●●●
Check the cylinder and piston for wear ●●●●●●
Check the eccentricity of the crankshaft journal ●●●●●●
Check the radial clearance of the conrod bearings ●●●
Check the radial clearance of the piston pin main bearing ●●●
Check the crankshaft main bearing for wear ●●●
Replace the crankshaft bearings and conrod bearings ●●●
Check the entire transmission including bearings for wear ●●●
30
hours
45
hours
60
hours
90
hours
120
hours
135
hours
NOTE: IFTHE INSPECTION ESTABLISHES THAT PERMISSIBLE TOLERANCES ARE EXCEEDED, THE RESPECTIVE COMPONENTS MUST BE REPLACED.

ENGLISH
16
Removing the seat
The quick-release mechanism 1allows 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 2of the top
triple clamp and the counternut 3. Turn the adjusting nut 4until 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 3reduces 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 15 Nm.
 WARNING 
IFTHE STEERING HEAD BEARING IS NOT ADJUSTED TO BE FREE OF CLEARANCE, THE
MOTORCYCLE WILL EXHIBIT UNSTEADY DRIVING CHARACTERISTICS AND CAN GET OUT OF
CONTROL.
! CAUTION !
–THE HANDLEBAR MUST MOVE EASILY. OTHERWISE THE BEARINGS WILL BE DAMAGED.
–I
FYOU 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).
MAINTENANCE WORK ON CHASSIS AND ENGINE
 WARNING 
MAINTENANCE WORK AND ADJUSTMENTS MARKED WITH AN ASTERISK (*) MUST BE PER-
FORMED BY AN EXPERT. TO PROTECT YOUR YOUNGSTER, ALWAYS HAVE SUCH WORK PER-
FORMED BY A SPECIALIZED KTM DEALER WHERE YOUR MOTORCYCLE WILL BE OPTIMALLY
SERVICED BY APPROPRIATELY QUALIFIED, SKILLED STAFF.
! CAUTION !
–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.
–B
EFORE CLEANING WITH WATER, PLUG THE EXHAUST PIPE TO PREVENT WATER INGRESS
–WHEN TRANSPORTING YOUR MOTORCYCLE, SECURE IT WITH ELASTIC STRAPS OR OTHER MECHANICAL DEVICES IN AN UPRIGHT POSITION.
BESURE THAT THE FUEL TAP IS CLOSED. IFTHE MOTORCYCLE TOPPLES OVER, FUEL CAN FLOW OUT OF THE CARBURETOR OR FUEL TANK.
–D
ONOT 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.
–L
ET YOUR MOTORCYCLE COOL DOWN BEFORE BEGINNING ANY MAINTENANCE WORK IN ORDER TO AVOID GETTING BURNED.
–D
ISPOSE OF OILS, FATTY MATTERS, FILTERS, FUELS, WASHING DETERGENTS, ETC. PROPERLY.
–U
NDER 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
2
4
3
1
24

ENGLISH
17
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 1on the upper triple clamp and
loosen the steering head screw 2by a few turns. Lift the triple clamp
slightly and turn the adjusting nut 3until 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 15 Nm.
 WARNING 
IFTHE STEERING HEAD BEARING IS NOT ADJUSTED TO BE FREE OF CLEARANCE, THE
MOTORCYCLE WILL EXHIBIT UNSTEADY DRIVING CHARACTERISTICS AND CAN GET OUT OF
CONTROL.
! CAUTION !
–THE HANDLEBAR MUST MOVE EASILY. OTHERWISE THE BEARINGS WILL BE DAMAGED.
–IFYOU 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 4includes 2 bores arranged at a distance of 15 mm (0.6 in)
from one another. The bores at the handlebar support 5are 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 6of the handlebar clamps and screws 7
of the handlebar support. Position handlebar support, and tighten screws
7to 40 Nm. Mount handlebar and handlebar clamps, and tighten screws
6to 20 Nm. The gap between the handlebar support and handlebar
clamps should be the same size in the front and in the rear.
! CAUTION !
THE SCREWS 7MUST BE SECURED WITH LOCTITE 243.
1
2
3
1
2
3
4
5
6
7
15 mm
3,5 mm

ENGLISH
18
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 deli-
very, 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 gro-
und.
– 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. 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 gro-
und.
–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 redu-
ced, 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).
A
B
C
D
1

ENGLISH
19
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 1from 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 2on the fork stabilizers and pull the fork legs
down out of the fork stabilizers.
! CAUTION !
–DONOT OPERATE THE HAND BRAKE WHEN THE FRONT WHEEL HAS BEEN
DISMOUNTED.
–M
AKE 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 4at 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 tigh-
ten 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 15 Nm.
Mount front wheel (see chapter: mounting the front wheel).
 WARNING 
THE SCREWS 1MUST 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.
 WARNING 
–I
TISVERY IMPORTANT TO KEEP THE BRAKE DISK FREE FROM OIL AND FATTY MAT-
TERS. OTHERWISE, THE BRAKING EFFECT WOULD BE STRONGLY REDUCED.
–A
FTER 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 cm3SAE 7.5 fork oil into each fork tube.
Slide the fork tube all the way into the slider tube.
Adjust the air-chamber length Ato 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).
4
3
A
2
12
5