KTM 250 SX 2021 User Manual

OWNER'S MANUAL 2021
250 SX
Art. no. 3214210en

KTM 250 SX 2021 Specifications

General

Engine Type	1-cylinder, 2-stroke engine
Displacement	249 cm³
Bore x Stroke	66.4 mm x 72 mm
Starter	Kickstarter
Transmission	5-speed
Front Suspension	WP XACT-USD, Ø 48 mm
Front Brake	Disc brake
Rear Brake	Disc brake
Fuel Tank Capacity	7.5 liters
Ground Clearance	375 mm
Seat Height	950 mm
Frame	Chromium Molybdenum Steel
Rear Suspension	WP XACT Monoshock

Summary

Means of Representation

Symbols Used

Explains the meaning of various symbols used in the manual for clarity.

Formats Used

Details the typographical formats like proprietary names and underlined terms.

Safety Advice

Use Definition – Intended Use

Defines the intended use of the vehicle for racing and compliance with regulations.

Misuse

Describes actions that constitute misuse of the vehicle and potential dangers.

Safety Advice

General instructions for safe operation and reference to highlighted safety information.

Degrees of Risk and Symbols

Explains the risk levels (Danger, Warning, Caution, Note) and associated symbols.

Safe Operation

Provides critical safety guidelines for operating the motorcycle responsibly.

Important Notes

Manufacturer Warranty, Implied Warranty

Details warranty conditions, voiding clauses, and authorized workshop requirements.

Fuel, Auxiliary Substances

Information on fuel types and environmental hazards associated with handling fuels.

Spare Parts, Accessories

Guidance on using approved spare parts and accessories for safety and performance.

Service

Emphasizes the importance of proper service for operation, wear prevention, and longevity.

View of Vehicle

View of Vehicle, Front Left (example)

Illustrates and labels key components visible from the front left side.

View of Vehicle, Rear Right (example)

Illustrates and labels key components visible from the rear right side.

Serial Numbers

Vehicle Identification Number

Shows the location of the VIN, stamped on the right side of the steering head.

Type Label

Indicates the location of the type label, fixed to the front of the steering head.

Engine Number

Specifies the location of the engine number on the left side of the engine.

Controls

Clutch Lever

Description and operation of the hydraulic clutch lever on the handlebar.

Hand Brake Lever

Details the location and function of the hand brake lever for the front brake.

Throttle Grip

Explains the location and operation of the throttle grip on the right handlebar.

Switch-off Button

Describes the function and states of the engine switch-off button.

Fuel Tap

Information on the fuel tap's location and function for controlling fuel supply.

Shift Lever

Details the location and function of the shift lever on the engine.

Preparing for Use

Advice on Preparing for First Use

Essential steps and safety precautions before the first ride.

Running in the Engine

Guidelines for the engine's running-in phase to ensure optimal performance and lifespan.

Preparing the Vehicle for Difficult Operating Conditions

Instructions for preparing the vehicle for challenging conditions like sand or mud.

Riding Instructions

Checks and Maintenance Measures When Preparing for Use

Pre-ride checks to ensure the vehicle is safe and in perfect technical condition.

Starting

Procedures and safety warnings for starting the motorcycle's engine.

Shifting, Riding

Guidance on gear shifting, riding techniques, and adapting speed to conditions.

Applying the Brakes

Instructions on proper brake application, including warnings about misuse.

Refueling

Safe procedures and precautions for refueling the motorcycle with fuel.

Service Schedule

Additional Information

Notes on service work, intervals, and obtaining the most up-to-date schedule.

Required Work

Lists the mandatory service tasks and their intervals (e.g., after every race, operating hours).

Recommended Work

Lists recommended service tasks for optimal performance and longevity.

Tuning the Chassis

Checking the Basic Chassis Setting with Rider's Weight

Guidance on adjusting suspension based on rider's weight for optimal handling.

Air Suspension XACT 5448

Details on the air suspension system used in the fork and its adjustment.

Compression Damping of the Shock Absorber

Explanation of high-speed and low-speed compression damping adjustment.

Adjusting the Spring Preload of the Shock Absorber

Procedure for adjusting the spring preload to influence sag and ride height.

Adjusting the Fork Air Pressure

Instructions for adjusting the air pressure in the fork for personalized suspension.

Service Work on the Chassis

Raising the Motorcycle with a Lift Stand

Procedure for safely lifting the motorcycle using a lift stand.

Removing the Fork Legs

Step-by-step instructions for removing the front fork legs.

Removing the Shock Absorber

Detailed procedure for safely removing the rear shock absorber.

Removing the Fuel Tank

Instructions for safely removing the fuel tank from the motorcycle.

Cleaning the Chain

Procedure for cleaning the drive chain to ensure proper maintenance.

Adjusting the Chain Tension

Steps for adjusting the chain tension to the correct specification.

Changing the Hydraulic Clutch Fluid

Procedure for changing the hydraulic clutch fluid for optimal clutch performance.

Brake System

Checking the Front Brake Fluid Level

Procedure for checking the brake fluid level in the front brake reservoir.

Adding Front Brake Fluid

Instructions on how to add front brake fluid safely and correctly.

Checking the Front Brake Linings

Guidance on checking the wear and condition of the front brake linings.

Changing the Front Brake Linings

Detailed steps for replacing the front brake linings for safety.

Checking the Rear Brake Fluid Level

Procedure for checking the brake fluid level in the rear brake reservoir.

Checking the Brake Linings of the Rear Brake

Guidance on checking the wear and condition of the rear brake linings.

Wheels, Tires

Removing the Front Wheel

Step-by-step instructions for removing the front wheel from the motorcycle.

Installing the Front Wheel

Procedure for correctly installing the front wheel onto the motorcycle.

Checking the Tire Condition

Guidance on inspecting tires for damage, wear, and age.

Checking Spoke Tension

Method for checking spoke tension to ensure wheel integrity and handling.

Cooling System

Checking the Antifreeze and Coolant Level

Instructions for checking coolant level and antifreeze protection.

Draining the Coolant

Procedure for safely draining the coolant from the system.

Refilling with Coolant

Steps for refilling the cooling system with the correct coolant.

Tuning the Engine

Checking Throttle Cable Play

Procedure for checking the correct play in the throttle cable.

Carburetor Tuning

Explains the effects of carburetor components on engine performance.

Carburetor Idle Control

Details the influence of idle settings on starting and engine response.

Engine Characteristic – Auxiliary Spring

Explains how auxiliary springs affect engine characteristics and their tuning.

Service Work on the Engine

Emptying the Carburetor Float Chamber

Procedure for emptying the carburetor float chamber to prevent issues.

Checking the Gear Oil Level

Instructions for checking the gear oil level when the engine is cold.

Changing the Gear Oil

Procedure for changing the engine's gear oil for proper lubrication.

Cleaning, Care

Cleaning the Motorcycle

Guidelines for regular cleaning to maintain the motorcycle's value and appearance.

Storage

Storage

Steps for preparing the motorcycle for long-term storage.

Preparing for Use After Storage

Procedures for getting the motorcycle ready after a period of storage.

Troubleshooting

Technical Data

Engine

Specifications related to the engine design, displacement, and components.

Engine Tightening Torques

Specific torque values for various engine screws and bolts.

Carburetor

Details on the carburetor type, settings, and tuning parameters.

Chassis

Specifications for the chassis, frame, suspension, and brake system components.

Fork

Technical data for the front fork, including damping and oil specifications.

Shock Absorber

Technical data for the shock absorber, including damping and spring specifications.

Substances

Brake Fluid DOT 4 / DOT 5.1

Specifications and recommended suppliers for brake fluid.

Coolant

Information on coolant types, antifreeze protection, and recommended suppliers.

Engine Oil (15W/50)

Specifications and recommended suppliers for 4-stroke engine oil.

Engine Oil, 2-Stroke

Specifications and recommended suppliers for 2-stroke engine oil.

Auxiliary Substances

Standards

List of Abbreviations