KTM 150 SX 2021 Manual

SETUP INSTRUCTIONS 2021
125 SX
150 SX
125 XC
Art. no. 3214364en

INTRODUCTION
*3214364en*
3214364en
02/2021
INTRODUCTION
Perform the work described in these setup instructions before the vehicle is delivered to the customer.
Read the setup instructions in their entirety before beginning work.
These setup instructions were written to correspond to the latest state of this series. We reserve the right to make
changes in the interest of technical advancement without at the same time updating this manual.
We shall not provide a description of general workshop methods. Likewise, safety rules that apply in a workshop
are not specified here. It is assumed that the work will be performed by a fully trained mechanic.
All specifications contained herein are non-binding. KTM Sportmotorcycle GmbH specifically reserves the right
to modify or delete technical specifications, prices, colors, forms, materials, services, designs, equipment, etc.,
without prior notice and without specifying reasons, to adapt these to local conditions, as well as to stop produc-
tion of a particular model without prior notice. KTM accepts no liability for delivery options, deviations from fig-
ures and descriptions, misprints, and other errors. The models portrayed partly contain special equipment that
does not belong to the regular scope of supply.
© 2021 KTM Sportmotorcycle GmbH, Mattighofen Austria
All rights reserved
Reproduction, even in part, as well as copying of all kinds, is permitted only with the express written permission
of the copyright owner.
ISO 9001(12 100 6061)
KTM applies quality assurance processes that lead to the highest possible product quality as
defined in the ISO 9001 international quality management standard.
Issued by: TÜV Management Service
KTM Sportmotorcycle GmbH
Stallhofnerstraße 3
5230 Mattighofen, Austria
This document is valid for the following models:
125 SX (F6101U0)
150 SX (F6101U1)
125 XC US (F6175U3)

1 MEANS OF REPRESENTATION
2
1.1 Symbols used
The meaning of specific symbols is described below.
Indicates an expected reaction (e.g. of a work step or a function).
Indicates an unexpected reaction (e.g. of a work step or a function).
Indicates a page reference (more information is provided on the specified page).
Indicates information with more details or tips.
Indicates the result of a testing step.
Indicates a voltage measurement.
Indicates a current measurement.
Indicates a resistance measurement.
Indicates the end of an activity including potential rework.
1.2 Formats used
The typographical formats used in this document are explained below.
Proprietary name Indicates a proprietary name.
Name®Indicates a protected name.
Brand™ Indicates a brand available on the open market.
Underlined terms Refer to technical details of the vehicle or indicate technical terms, which
are explained in the glossary.

SETUP 2
3
2.1 Unpacking and setting up the vehicle
E00851-10
Package 2
–Remove the box and the plastic packaging.
Info
To avoid damaging the motorcycle during the setup,
leave the protective film on the vehicle until you
have finished.
–Remove the separate enclosure and unpack it. Check that
the scope of supply is complete using the enclosed pack-
ing list.
Info
The procedure in the event of missing parts is
described in the customer service manual.
–Have a lift stand available.
Lift stand (78129955100)
–Carefully loosen and remove the tension belt of the footrest
mount.
Info
An assistant prevents the motorcycle from falling
over.
402050-01
–Together with an assistant, take the vehicle off the pallet.
–Position the vehicle on a lift stand.
–Check the vehicle for transport damage.
Info
The procedure in the event of transport damage is
described in the customer service manual.
E00850-10
Package 12
–Remove the box and the plastic packaging.
Info
An assistant prevents the motorcycle from falling
over.
To avoid damaging the motorcycle during the setup,
leave the protective film on the vehicle until you
have finished.
–Remove the separate enclosure and unpack it. Check that
the scope of supply is complete using the enclosed pack-
ing list.
Info
The procedure in the event of missing parts is
described in the customer service manual.

2 SETUP
4
–Have a lift stand available.
Lift stand (78129955100)
–Together with an assistant, take the vehicle off the pallet.
402051-01
–Position the vehicle on a lift stand.
–Check the vehicle for transport damage.
Info
The procedure in the event of transport damage is
described in the customer service manual.
A00001-11
–Remove the cardboard from around the shock absorber.
–Position the angle lever and linkage lever.
–Mount and tighten fitting 1.
Guideline
Nut, linkage lever
on angle lever
M14x1.5 60 Nm
(44.3 lbf ft)
–Mount and tighten screw 2.
Guideline
Screw, bottom
shock absorber
M10 60 Nm (44.3 lbf ft)
Loctite®2701™
Info
Raise the wheel slightly to be able to mount the
screw more easily.
–Route the clutch line with the clutch master cylinder
toward the front between the upper and lower triple
clamps.
–Install the fork legs. ( p. 10)

SETUP 2
5
K00620-10
–Remove screws 3. Take off the handlebar clamp. Remove
the handlebar and lay it to one side.
Info
Cover the components to protect them against damage.
Do not kink the cables and lines.
–Remove screws 4. Take off handlebar supports 5.
–Position rubber bushings 6and push through nuts 7from
below.
–Place handlebar supports in required position.
Info
The handlebar supports are longer and higher on one
side.
Position the left and right handlebar supports evenly.
–Mount and tighten screws 4.
Guideline
Screw, handle-
bar support
M10 40 Nm (29.5 lbf ft)
Loctite®243™
Warning
Danger of accidents A repaired handlebar poses a
safety risk.
If the handlebar is bent or straightened, the mate-
rial becomes fatigued. The handlebar may break as a
result.
–Change the handlebar if the handlebar is damaged
or bent.
–Position the handlebar.
Info
Make sure the cables and wiring are positioned cor-
rectly.
–Position the handlebar clamp.
–Mount screws 3, but do not tighten yet.
–First bolt the handlebar clamp with screws 3onto the longer,
higher side of the handlebar supports so that both parts touch.
–Tighten screws 3evenly.
Guideline
Screw, handlebar
clamp
M8 20 Nm (14.8 lbf ft)

2 SETUP
6
F01707-01
–Position the controls on the right half of the handlebar.
F01706-01
–Position the controls on the left handlebar half.
–Mount the cable ties.
–Mount the fuel tank breather.
–Install the front wheel. ( p. 10)
–Install front fender. ( p. 11)
–Install the start number plate. ( p. 12)
F01708-01
–Mount the handlebar cushion.
R01229-10
–Position the new footrest and pin.
Info
Only insert the pin to the extent that the spring can still
be mounted.

SETUP 2
7
K00621-10
–Position spring as shown.
Spring Aengages in area B.
K00622-10
–Press the spring with special tool 8.
Footrest spring plier (79029083000)
The special tool is applied to area Con the footrest.
–Mount pin 9.
K00623-10
–Mount the washer and splint bk.
–Repeat these steps on the opposite side.
F01705-10
–Position the left frame protector.
–Insert the right frame protector from below and push it to the
rear.
–Mount and tighten screws bl with the washers.
Guideline
Screw, frame protec-
tor
M5 3 Nm (2.2 lbf ft)
–Mount and tighten screw bm.
Guideline
Screw, frame protec-
tor
M5 3 Nm (2.2 lbf ft)
–Mount the cable ties.

2 SETUP
8
–Unpack and mount the KTM PowerParts included in the deliv-
ery (optional).
Info
Read the accompanying KTM PowerParts fitting instruc-
tions.
–Attach the stickers included in the scope of supply (optional).
–Refuel. ( p. 13)
–Position all controls in their exact positions on the handlebar.
Tighten all screws.
–Remove the remaining films, the padding, the corrugated card-
board, and the other packaging material.
–Prepare the vehicle according to the specifications in
KTM Dealer.net for handover to the customer.

WORK 3
9
3.1 Raising the motorcycle with a lift stand
Note
Material damage The vehicle may be damaged by incorrect procedure when parking.
Significant damage may be caused if the vehicle rolls away or falls over.
The components for parking the vehicle are designed only for the weight of the vehicle.
–Park the vehicle on a firm and level surface.
–Ensure that nobody sits on the vehicle when the vehicle is parked on a stand.
401942-01
–Raise the motorcycle at the frame underneath the engine.
Lift stand (78129955100)
Neither wheel is in contact with the ground.
–Secure the motorcycle against falling over.
3.2 Removing the motorcycle from the lift stand
Note
Material damage The vehicle may be damaged by incorrect procedure when parking.
Significant damage may be caused if the vehicle rolls away or falls over.
The components for parking the vehicle are designed only for the weight of the vehicle.
–Park the vehicle on a firm and level surface.
–Ensure that nobody sits on the vehicle when the vehicle is parked on a stand.
H02629-10
(125/150 SX)
–Remove the motorcycle from the lift stand.
–Remove the lift stand.
–To park the motorcycle, insert plug-in stand 1into the
left side of the wheel spindle.
Info
Remove the plug-in stand before riding.
401943-10
(125 XC US)
–Remove the motorcycle from the lift stand.
–Remove the lift stand.
–To park the motorcycle, press side stand 1to the ground
with your foot and lean the motorcycle on it.
Info
When you are riding, the side stand must be folded
up and secured with the rubber strap.

3 WORK
10
3.3 Installing the fork legs
H01182-10
Main work
–Position the fork legs.
Air bleeder screw 1of the right fork leg is positioned to
the front.
Valve Aof the left fork leg faces the front.
Info
Grooves are milled into the side of the upper end of the
fork legs. The second milled groove (from the top) must
be flush with the upper edge of the upper triple clamp.
The air suspension is located in the left fork leg. The
pressure and rebound damping is located in the right
fork leg.
K01174-11
–Tighten screws 2.
Guideline
Screw, top triple
clamp
M8 17 Nm (12.5 lbf ft)
–Tighten screws 3.
Guideline
Screw, bottom triple
clamp
M8 12 Nm (8.9 lbf ft)
K01143-11
–Position the brake caliper. Mount and tighten screws 4.
Guideline
Screw, front
brake caliper
M8 25 Nm (18.4 lbf ft)
Loctite®243™
–Position the brake line and the clamp. Mount and tighten
screws 5.
Finishing work
–Install the front wheel. ( p. 10)
3.4 Installing the front wheel
Warning
Danger of accidents Oil or grease on the brake discs reduces the braking effect.
–Always keep the brake discs free of oil and grease.
–Clean the brake discs with brake cleaner when necessary.

WORK 3
11
H00935-10
–Check the wheel bearing for damage and wear.
» If the wheel bearing is damaged or worn:
–Change front wheel bearing.
–Clean and grease shaft seal rings 1and contact surfaces A
of the spacers.
Long-life grease ( p. 19)
–Insert the spacers.
–Clean and grease the wheel spindle.
Long-life grease ( p. 19)
K00454-11
–Position the front wheel and insert the wheel spindle.
The brake linings are correctly positioned.
–Mount and tighten screw 2.
Guideline
Screw, front wheel
spindle
M20x1.5 35 Nm (25.8 lbf ft)
–Operate the hand brake lever several times until the brake lin-
ings are seated correctly against the brake disc.
–Remove the motorcycle from the lift stand. ( p. 9)
–Operate the front brake and compress the fork a few times
firmly.
The fork legs straighten.
–Tighten screws 3.
Guideline
Screw, fork stub M8 15 Nm (11.1 lbf ft)
3.5 Installing front fender
M01144-10
Main work
–Position front fender. Mount and tighten screws 1and 2.
Guideline
Remaining screws,
chassis
M6 10 Nm (7.4 lbf ft)
Finishing work
–Install the start number plate. ( p. 12)

3 WORK
12
3.6 Installing the start number plate
F00013-10
–Connect the brake line at the start number plate.
–Position the start number plate.
The holding lugs engage in the fender.
–Mount and tighten screw 1.
3.7 Removing the seat
K01133-10
–Remove screw 1.
H02218-10
–Raise the rear of the seat, pull the seat back, and lift it off.
3.8 Mounting the seat
H02218-11
–Mount the front of the seat on the collar bushing of the fuel
tank, lower the seat at the rear, and push the seat forward.
–Make sure that the seat is locked in correctly.

WORK 3
13
K01133-10
–Mount and tighten screw 1.
Guideline
Remaining screws,
chassis
M6 10 Nm (7.4 lbf ft)
3.9 Refueling
Danger
Fire hazard Fuel is highly flammable.
The fuel in the fuel tank expands when warm and can escape if overfilled.
–Do not fuel the vehicle in the vicinity of open flames or lit cigarettes.
–Switch off the engine for refueling.
–Make sure that no fuel is spilled; particularly not on hot parts of the vehicle.
–If any fuel is spilled, wipe it off immediately.
–Observe the specifications for refueling.
Warning
Danger of poisoning Fuel is poisonous and a health hazard.
–Avoid skin, eye and clothing contact with fuel.
–Immediately consult a doctor if you swallow fuel.
–Do not inhale fuel vapors.
–In case of skin contact, rinse the affected area with plenty of water.
–Rinse the eyes thoroughly with water, and consult a doctor in case of fuel contact with the eyes.
–Change your clothing in case of fuel spills on them.
Note
Environmental hazard Improper handling of fuel is a danger to the environment.
–Do not allow fuel to enter the groundwater, the soil, or the sewage system.
–Switch off the engine.
–Open the fuel tank filler cap. ( p. 14)
400382-10
–Fill the fuel tank with fuel up to measurement A.
Guideline
Measurement of A35 mm (1.38 in)
Total fuel tank
capacity, approx.
(125/150 SX)
7.5 l
(1.98 US gal)
Super unleaded
(98 octane) mixed
with 2-stroke
engine oil (1:40)
( p. 18)
Total fuel tank
capacity, approx.
(125 XC US)
10 l
(2.6 US gal)
Super unleaded
(98 octane) mixed
with 2-stroke
engine oil (1:40)
( p. 18)

3 WORK
14
Engine oil, 2-stroke ( p. 18)
–Close the fuel tank filler cap. ( p. 15)
3.10 Opening the fuel tank filler cap
Danger
Fire hazard Fuel is highly flammable.
The fuel in the fuel tank expands when warm and can escape if overfilled.
–Do not fuel the vehicle in the vicinity of open flames or lit cigarettes.
–Switch off the engine for refueling.
–Make sure that no fuel is spilled; particularly not on hot parts of the vehicle.
–If any fuel is spilled, wipe it off immediately.
–Observe the specifications for refueling.
Warning
Danger of poisoning Fuel is poisonous and a health hazard.
–Avoid skin, eye and clothing contact with fuel.
–Immediately consult a doctor if you swallow fuel.
–Do not inhale fuel vapors.
–In case of skin contact, rinse the affected area with plenty of water.
–Rinse the eyes thoroughly with water, and consult a doctor in case of fuel contact with the eyes.
–Change your clothing in case of fuel spills on them.
–Keep fuels correctly in a suitable canister, and out of the reach of children.
Note
Environmental hazard Improper handling of fuel is a danger to the environment.
–Do not allow fuel to enter the groundwater, the soil, or the sewage system.
K01132-11
(125/150 SX)
–Turn fuel tank filler cap 1counterclockwise and lift it
off.
K01334-10
(125 XC US)
–Press release button 1, turn the fuel tank filler cap coun-
terclockwise, and lift it off.

WORK 3
15
3.11 Closing the fuel tank filler cap
K01132-10
(125/150 SX)
–Mount fuel tank filler cap 1and turn it clockwise until
the fuel tank is tightly closed.
Info
Route fuel tank breather hose 2without kinks.
K01334-11
(125 XC US)
–Mount filler cap 1and turn it clockwise until the release
button engages.
Info
Route fuel tank breather hose 2without kinks.

4 TECHNICAL DATA
16
4.1 Chassis tightening torques
Screw, stop button M3 0.4 Nm (0.3 lbf ft)
Screw, fixed grip M4 5 Nm (3.7 lbf ft)
Loctite®243™
Screw, service hour counter M4 0.8 Nm (0.59 lbf ft)
Spoke nipple, front wheel M4.5 6 Nm (4.4 lbf ft)
Spoke nipple, rear wheel M4.5 6 Nm (4.4 lbf ft)
Remaining nuts, chassis M5 5 Nm (3.7 lbf ft)
Remaining screws, chassis M5 5 Nm (3.7 lbf ft)
Screw, shock absorber adjusting
ring
M5 5 Nm (3.7 lbf ft)
Screws on main silencer M5 7 Nm (5.2 lbf ft)
Remaining nuts, chassis M6 10 Nm (7.4 lbf ft)
Remaining screws, chassis M6 10 Nm (7.4 lbf ft)
Screw, absorbing element on frame M6 6 Nm (4.4 lbf ft)
Screw, absorbing element on mani-
fold
M6 6 Nm (4.4 lbf ft)
Screw, ball joint of push rod on
foot brake cylinder
M6 10 Nm (7.4 lbf ft)
Loctite®243™
Screw, chain sliding guard M6 10 Nm (7.4 lbf ft)
Loctite®243™
Screw, front brake disc M6 14 Nm (10.3 lbf ft)
Loctite®243™
Screw, rear brake disc M6 14 Nm (10.3 lbf ft)
Loctite®243™
Screw, throttle grip M6 5 Nm (3.7 lbf ft)
Nut, foot brake lever stop M8 20 Nm (14.8 lbf ft)
Nut, rear sprocket screw M8 35 Nm (25.8 lbf ft)
Loctite®2701™
Nut, rim lock M8 12 Nm (8.9 lbf ft)
Remaining nuts, chassis M8 25 Nm (18.4 lbf ft)
Remaining screws, chassis M8 25 Nm (18.4 lbf ft)
Screw, bottom triple clamp M8 12 Nm (8.9 lbf ft)
Screw, chain sliding piece M8 15 Nm (11.1 lbf ft)
Screw, engine brace on engine M8x20 25 Nm (18.4 lbf ft)
Loctite®243™
Screw, engine brace on frame M8x15 25 Nm (18.4 lbf ft)
Loctite®2701™
Screw, fork stub M8 15 Nm (11.1 lbf ft)
Screw, front brake caliper M8 25 Nm (18.4 lbf ft)
Loctite®243™
Screw, handlebar clamp M8 20 Nm (14.8 lbf ft)
Screw, manifold M8 15 Nm (11.1 lbf ft)
Screw, subframe bottom M8x18 30 Nm (22.1 lbf ft)
Loctite®2701™
Screw, subframe top M8x20 35 Nm (25.8 lbf ft)
Loctite®2701™

TECHNICAL DATA 4
17
Screw, top steering stem M8 20 Nm (14.8 lbf ft)
Loctite®243™
Screw, top triple clamp M8 17 Nm (12.5 lbf ft)
Engine bracket screw M10 60 Nm (44.3 lbf ft)
Remaining nuts, chassis M10 45 Nm (33.2 lbf ft)
Remaining screws, chassis M10 45 Nm (33.2 lbf ft)
Screw, bottom shock absorber M10 60 Nm (44.3 lbf ft)
Loctite®2701™
Screw, handlebar support M10 40 Nm (29.5 lbf ft)
Loctite®243™
Screw, top shock absorber M10 60 Nm (44.3 lbf ft)
Loctite®2701™
Nut, angle lever to link fork M14x1.5 60 Nm (44.3 lbf ft)
Nut, frame on linkage lever M14x1.5 60 Nm (44.3 lbf ft)
Nut, linkage lever on angle lever M14x1.5 60 Nm (44.3 lbf ft)
Nut, fork pivot M16x1.5 100 Nm (73.8 lbf ft)
Screw, front wheel spindle M20x1.5 35 Nm (25.8 lbf ft)
Screw, top steering head M20x1.5 12 Nm (8.9 lbf ft)
Screw-in fitting, cooling system M24x1.5 18 Nm (13.3 lbf ft)
Loctite®243™
Nut, rear wheel spindle M25x1.5 80 Nm (59 lbf ft)

5 SUBSTANCES
18
Engine oil, 2-stroke
Standard/classification
–JASO FD ( p. 20)
Guideline
–Only use high-grade 2-stroke engine oil from a reputable brand.
fully synthetic
Recommended supplier
MOTOREX®
–Cross Power 2T
Super unleaded (ROZ 98 / RON 98 / PON 94)
Standard/classification
–DIN EN 228 (ROZ 98 / RON 98 / PON 94)
Super unleaded (98 octane) mixed with 2-stroke engine oil (1:40)
Standard/classification
–DIN EN 228
–JASO FD ( p. 20) (1:40)
Mixture ratio
1:40 Engine oil, 2-stroke ( p. 18)
Super unleaded (ROZ 98 / RON 98 / PON 94) ( p. 18)
Recommended supplier
MOTOREX®
–Cross Power 2T