Contents

1 MEANS OF REPRESENTATION
- 1.1 Symbols used
- 1.2 Formats used
2 SAFETY ADVICE
- 2.1 Use definition - intended use
- 2.2 Safety advice
- 2.3 Degrees of risk and symbols
- 2.4 Tampering warning
- 2.5 Safe operation
- 2.6 Protective clothing
- 2.7 Work rules
- 2.8 Environment
- 2.9 Owner's Manual
3 IMPORTANT INFORMATION
- 3.1 Guarantee, warranty
- 3.2 Operating and auxiliary substances
- 3.3 Spare parts, accessories
- 3.4 Service
- 3.5 Figures
- 3.6 Customer service
4 VIEW OF VEHICLE
- 4.1 View of the vehicle from the left front (example)
- 4.2 View of vehicle, rear right (example)
5 SERIAL NUMBERS
- 5.1 Chassis number
- 5.2 Type label
- 5.3 Engine number
- 5.4 Fork part number
- 5.5 Shock absorber part number
6 CONTROLS
- 6.1 Clutch lever
- 6.2 Hand brake lever
- 6.3 Throttle grip
- 6.4 Kill switch
- 6.5 Electric starter button (All XC models)
- 6.6 Opening the filler cap
- 6.7 Closing the filler cap
- 6.8 Fuel tap (All SX models)
- 6.9 Fuel tap (All XC models)
- 6.10 Choke
- 6.11 Shift lever
- 6.12 Kick starter
- 6.13 Foot brake lever
- 6.14 Plug-in stand (All SX models)
- 6.15 Side stand (All XC models)
7 PREPARING FOR USE
- 7.1 Advice on first use
- 7.2 Running in the engine
- 7.3 Preparing the vehicle for difficult riding conditions
- 7.4 Preparations for riding on dry sand
- 7.5 Preparations for riding on wet sand
- 7.6 Preparations for riding on wet and muddy surfaces
- 7.7 Preparations for riding at high temperatures and low speeds
- 7.8 Preparing for riding at low temperatures or in snow
8 RIDING INSTRUCTIONS
- 8.1 Checks and maintenance work when preparing for use
- 8.2 Starting
- 8.3 Starting off
- 8.4 Shifting, riding
- 8.5 Braking
- 8.6 Stopping, parking
- 8.7 Transport
- 8.8 Refueling
9 SERVICE SCHEDULE
- 9.1 All SX models
  - 9.1.1 Service schedule
  - 9.1.2 Service work (as additional order)
- 9.2 All XC models
  - 9.2.1 Service schedule
  - 9.2.2 Service work (as additional order)
10 TUNING THE CHASSIS
- 10.1 Checking the basic chassis setting with the rider's weight
- 10.2 Compression damping of shock absorber
- 10.3 Adjusting the low-speed compression damping of the shock absorber
- 10.4 Adjusting the high-speed compression damping of the shock absorber
- 10.5 Adjusting the rebound damping of the shock absorber
- 10.6 Measuring the sag of the unloaded rear wheel
- 10.7 Checking the static sag of the shock absorber
- 10.8 Checking the riding sag of the shock absorber
- 10.9 Adjusting the spring preload of the shock absorber x
- 10.10 Adjusting the riding sag x
- 10.11 Checking the basic setting of the fork
- 10.12 Adjusting the compression damping of the fork
- 10.13 Adjusting the rebound damping of the fork
- 10.14 Handlebar position
- 10.15 Adjusting the handlebar position x
11 SERVICE WORK ON THE CHASSIS
- 11.1 Raising the motorcycle with the lift stand
- 11.2 Removing the motorcycle from the lift stand
- 11.3 Bleeding the fork legs
- 11.4 Cleaning the dust boots of the fork legs
- 11.5 Removing the fork legs x
- 11.6 Installing the fork legs x
- 11.7 Removing the fork protector
- 11.8 Installing the fork protector
- 11.9 Removing the lower triple clamp x
- 11.10 Installing the lower triple clamp x
- 11.11 Checking the play of the steering head bearing
- 11.12 Adjusting the play of the steering head bearing x
- 11.13 Greasing the steering head bearing x
- 11.14 Removing the start number plate
- 11.15 Installing the start number plate
- 11.16 Removing the front fender
- 11.17 Installing the front fender
- 11.18 Removing the shock absorber x
- 11.19 Installing the shock absorber x
- 11.20 Removing the seat
- 11.21 Mounting the seat
- 11.22 Removing the air filter box lid
- 11.23 Installing the air filter box lid
- 11.24 Removing the air filter x
- 11.25 Cleaning the air filter and air filter box x
- 11.26 Installing the air filter x
- 11.27 Securing the air filter box lid x
- 11.28 Sealing the air filter box x
- 11.29 Removing the main silencer
- 11.30 Installing the main silencer
- 11.31 Changing the glass fiber yarn filling of the main silencer x
- 11.32 Removing the fuel tank x
- 11.33 Installing the fuel tank x
- 11.34 Checking the chain for dirt
- 11.35 Cleaning the chain
- 11.36 Checking the chain tension
- 11.37 Adjusting the chain tension
- 11.38 Checking the chain, rear sprocket, engine sprocket and chain guide
- 11.39 Checking the frame x
- 11.40 Checking the swingarm x
- 11.41 Checking the routing of the throttle cable
- 11.42 Checking the rubber grip
- 11.43 Additionally securing the rubber grip
- 11.44 Adjusting the basic position of the clutch lever
- 11.45 Checking/correcting the fluid level of the hydraulic clutch
- 11.46 Changing the hydraulic clutch fluid x
12 BRAKE SYSTEM
- 12.1 Checking the free travel of the hand brake lever
- 12.2 Adjusting the basic position of the hand brake lever
- 12.3 Checking the brake discs
- 12.4 Checking the front brake fluid level
- 12.5 Adding front brake fluid x
- 12.6 Checking the front brake linings
- 12.7 Changing the front brake linings x
- 12.8 Checking the free travel of foot brake lever
- 12.9 Adjusting the basic position of the foot brake lever x
- 12.10 Checking the rear brake fluid level
- 12.11 Adding brake fluid for the rear brake x
- 12.12 Checking the rear brake linings
- 12.13 Changing the rear brake linings x
13 WHEELS, TIRES
- 13.1 Removing the front wheel x
- 13.2 Installing the front wheel x
- 13.3 Removing the rear wheel x
- 13.4 Installing the rear wheel x
- 13.5 Checking the tire condition
- 13.6 Checking the tire air pressure
- 13.7 Checking the spoke tension
14 ELECTRICAL SYSTEM
- 14.1 Removing the battery x (All XC models)
- 14.2 Installing the battery x (All XC models)
- 14.3 Recharging the battery x (All XC models)
- 14.4 Changing the main fuse (All XC models)
15 COOLING SYSTEM
- 15.1 Cooling system
- 15.2 Radiator cover (All SX models)
- 15.3 Installing the radiator cover (All SX models)
- 15.4 Removing the radiator cover (All SX models)
- 15.5 Checking the antifreeze and coolant level
- 15.6 Checking the coolant level
- 15.7 Draining the coolant x
- 15.8 Refilling with coolant x
16 TUNING THE ENGINE
- 16.1 Checking the play in the throttle cable
- 16.2 Adjusting the play in the throttle cable x
- 16.3 Carburetor - idle
- 16.4 Carburetor - adjusting the idle speed x
- 16.5 Emptying the carburetor float chamber x
- 16.6 Plug-in connection, ignition timing map
- 16.7 Changing the ignition curve
- 16.8 Checking the basic position of the shift lever
- 16.9 Adjusting the basic position of the shift lever x
- 16.10 Engine characteristic - auxiliary spring (All 250/300 models)
- 16.11 Engine characteristic - set the auxiliary spring x (All 250/300 models)
17 SERVICE WORK ON THE ENGINE
- 17.1 Checking the gear oil level
- 17.2 Changing the gear oil x
- 17.3 Draining the gear oil x
- 17.4 Refilling with gear oil x
- 17.5 Adding gear oil x
18 CLEANING, CARE
- 18.1 Cleaning the motorcycle
19 STORAGE
- 19.1 Storage
- 19.2 Preparing for use after storage
20 TROUBLESHOOTING
21 TECHNICAL DATA
- 21.1 Engine
  - 21.1.1 125 SX EU, 125 SX US
  - 21.1.2 150 SX EU, 150 SX US
  - 21.1.3 250 SX EU, 250 SX US
  - 21.1.4 250 XC EU/US
  - 21.1.5 300 XC EU/US
- 21.2 Engine tightening torques
  - 21.2.1 125/150 SX
  - 21.2.2 250 SX EU, 250 SX US
  - 21.2.3 All XC models
- 21.3 Carburetor
  - 21.3.1 125 SX EU, 125 SX US
  - 21.3.2 Carburetor - basic setting for sandy surfaces (125 SX EU, 125 SX US)
  - 21.3.3 Carburetor tuning (125 SX EU, 125 SX US)
  - 21.3.4 150 SX EU, 150 SX US
  - 21.3.5 Carburetor - basic setting for sandy surfaces (150 SX EU, 150 SX US)
  - 21.3.6 Carburetor tuning (150 SX EU, 150 SX US)
  - 21.3.7 250 SX EU, 250 SX US
  - 21.3.8 Carburetor - basic setting for sandy surfaces (250 SX EU, 250 SX US)
  - 21.3.9 Carburetor tuning (250 SX EU, 250 SX US)
  - 21.3.10 250 XC EU/US
  - 21.3.11 Carburetor tuning (250 XC EU/US)
  - 21.3.12 300 XC EU/US
  - 21.3.13 Carburetor tuning (300 XC EU/US) x
- 21.4 Capacities
  - 21.4.1 Gear oil
  - 21.4.2 Coolant
  - 21.4.3 Fuel
- 21.5 Chassis
- 21.6 Electrical system
- 21.7 Tires
- 21.8 Fork
  - 21.8.1 125 SX EU, 150 SX EU
  - 21.8.2 125 SX US, 150 SX US
  - 21.8.3 250 SX EU
  - 21.8.4 250 SX US
  - 21.8.5 All XC models
- 21.9 Shock absorber
  - 21.9.1 125/150 SX
  - 21.9.2 250 SX EU
  - 21.9.3 250 SX US
  - 21.9.4 All XC models
- 21.10 Chassis tightening torques
22 SUBSTANCES
23 AUXILIARY SUBSTANCES
24 STANDARDS
INDEX
- A
- B
- C
- D
- E
- F
- G
- H
- I
- K
- L
- M
- O
- P
- R
- S
- T
- U
- V
- W

KTM SX 125 EU 2015 Owner's Manual

KTM SX 125 EU 2015 Motorcycle manual cover

Pages 129

Year 2015

Language(s)

of 129

KTM SX 125 EU 2015 Motorcycle Specification

The KTM SX 125 EU 2015 is a high-performance motocross motorcycle designed for competitive racing and advanced off-road riding. This model is powered by a 124.8 cc, single-cylinder, two-stroke engine featuring a reed valve and exhaust control. The engine, known for its high power-to-weight ratio, is paired with a six-speed transmission, providing a wide range of gearing options for various terrains and riding styles. The chassis is constructed from lightweight, high-strength chromoly steel, ensuring optimal rigidity and handling precision.

The front suspension consists of WP upside-down 48 mm forks with 300 mm of travel, while the rear suspension is a WP monoshock with linkage, offering 310 mm of travel. These suspension components are fully adjustable, allowing riders to tailor the bike's response to their preferences and the demands of the track. The braking system includes a 260 mm disc with a two-piston caliper at the front and a 220 mm disc with a single-piston caliper at the rear, delivering strong and reliable stopping power.

The KTM SX 125 EU 2015 features a lightweight aluminum swingarm and a robust wheelset with CNC-machined hubs and high-performance spokes, ensuring durability and reduced unsprung weight. The ergonomics are designed for aggressive riding, with a slim profile, grippy seat cover, and adjustable handlebar position. The fuel tank has a capacity of 7.5 liters, providing adequate range for racing scenarios.

Overall, the KTM SX 125 EU 2015 is engineered for agility, power, and durability, making it a top choice for riders seeking a competitive edge in motocross racing. Its advanced engineering, combined with KTM's racing heritage, ensures it meets the demands of both amateur and professional riders alike.

KTM SX 125 EU 2015 Motorcycle F.A.Q.

How do I properly break in a new KTM SX 125 EU 2015 engine?

To break in a new engine, start by riding at varying speeds and avoid full throttle for the first few hours. Gradually increase speed and load after the first 1-2 hours of moderate riding. Always let the engine cool down between rides.

What type of oil is recommended for the KTM SX 125 EU 2015?

The recommended oil for the KTM SX 125 EU 2015 is high-quality, fully synthetic 2-stroke engine oil. Ensure it meets the JASO FD or ISO-L-EGD specifications for optimal performance.

How can I troubleshoot a starting problem with the KTM SX 125 EU 2015?

Check the spark plug for fouling, ensure the fuel is fresh, and inspect the carburetor for blockages. Also, verify that the ignition system is functioning properly and that the air filter is clean.

What is the recommended maintenance schedule for the KTM SX 125 EU 2015?

Regular maintenance includes checking and cleaning the air filter every 5 hours, inspecting the chain tension and lubrication every ride, and replacing the spark plug every 20 hours. Additionally, conduct a full service including oil change every 40 hours.

How do I adjust the suspension on my KTM SX 125 EU 2015 for different terrains?

Adjust the suspension by altering the compression and rebound damping settings. For rough terrains, soften the suspension by reducing compression damping. For smoother tracks, increase damping for a firmer ride. Always refer to the user manual for specific settings.

Why is my KTM SX 125 EU 2015 overheating and how can I fix it?

Check the coolant level and ensure there are no leaks in the cooling system. Ensure the radiator is clean and not blocked by debris. Additionally, verify that the carburetor jetting is correct and not causing a lean running condition.

What is the proper way to clean the air filter on a KTM SX 125 EU 2015?

Remove the air filter and wash it with a mild detergent and warm water. Allow it to dry completely, then apply air filter oil evenly. Reinstall the filter ensuring it is seated correctly to prevent dirt ingress.

How do I check and adjust the chain tension on the KTM SX 125 EU 2015?

To check the chain tension, measure the slack in the middle of the chain span; it should be about 1-2 inches. To adjust, loosen the axle nut and turn the adjusters evenly on both sides, then retighten the axle nut securely.

What spark plug should be used in the KTM SX 125 EU 2015?

The recommended spark plug for the KTM SX 125 EU 2015 is NGK BR8EG or a similar high-performance spark plug with the same heat range and dimensions.

How can I improve the performance of my KTM SX 125 EU 2015?

Regular maintenance is key. Additionally, consider upgrading the exhaust system, optimizing carburetor jetting, or installing a high-performance air filter. Always ensure modifications are compatible and do not void the warranty.