KTM 50 SX User Manual (English)

Other manuals for KTM 50 SX

Repair Manual159 pages

Setup Instructions19 pages

Questions and Answers:

M
Monique RobinsonAug 17, 2025
Why is my KTM 50 SX Motorcycle engine overheating?
- S
  Stephanie ButlerAug 18, 2025
  If your KTM Motorcycle engine is overheating, check the following: ensure there's enough coolant in the system, and bleed it if necessary. Clean the radiator fins with a water jet. Use a branded anti-freeze coolant. Ride faster or reduce clutch spring preload. Replace any pinched or kinked water hoses. Readjust the ignition timing and secure screws. Measure and adjust the compression ratio. Possible causes include insufficient coolant, clogged radiator fins, frothing in the cooling system, slow driving with clutch slippage, pinched water hoses, incorrect ignition timing, and incorrect compression ratio.
J
Jennifer SampsonAug 21, 2025
Why does my KTM Motorcycle have less engine power?
- R
  Rebecca Alvarez DVMAug 21, 2025
  If your KTM Motorcycle engine has less power, you should clean or replace the air filter. Blow through the fuel pipe and clean the carburetor. Tighten the spark plug. Check the exhaust system for damage. Check and adjust the ignition. Replace the reed paddles or reed valve housing. Overhaul the engine. This can happen because of an obstructed air filter, partly interrupted or blocked fuel supply, loss of compression due to a loose spark plug, damaged exhaust system, not enough preignition, tensionless or damaged reed paddles, or wear.
D
Diana MartinezAug 25, 2025
What to do if KTM Motorcycle engine splutters into the carburetor?
- L
  Lauren LeonAug 25, 2025
  If your KTM Motorcycle engine splutters into the carburetor, you should clean the fuel pipes, check the tank aeration, and clean it if necessary. Fit the correct spark plug. Check if the intake flange and carburetor are firmly set. This may be caused by a lack of fuel, a spark plug with an incorrect heat value, or the engine taking air out of control.
R
richardmooreAug 28, 2025
What to do if KTM Motorcycle engine is stalling?
- H
  Heather MendozaAug 28, 2025
  If your KTM Motorcycle engine is stalling or running with a four-stroke cycle, you should clean the carburetor, and if necessary, replace the float needle and adjust the level. Also, tighten the jets. This issue may arise if the carburetor overflows due to a level that is adjusted too high, a dirty or enlarged float needle seating, or loose carburetor jets.
R
Richard PeckAug 31, 2025
How to fix high rpm misfiring on a KTM Motorcycle?
- K
  kevin88Aug 31, 2025
  To resolve high RPM misfiring in your KTM Motorcycle, refer to the technical data section for the correct spark plug. Check and seal the ignition socket connector with silicon. This issue can be caused by an incorrect heat range or low-quality spark plug, or a loose, corroded, or non-conductive ignition socket connector.
M
mfrankSep 3, 2025
Why KTM 50 SX Motorcycle engine is not running at idle?
- K
  Kimberly SimmonsSep 4, 2025
  To fix a KTM Motorcycle engine without idle running, readjust the idle running or replace the idle adjusting screw. Examine the ignition system. Overhaul the engine. This problem may be caused by the idle adjusting screw being out of adjustment, a damaged ignition system, or wear.
J
jacobjohnsonSep 7, 2025
What causes excessive oil to escape from KTM Motorcycle transmission breather tube?
- S
  Scott CastilloSep 7, 2025
  If there is excessive oil escaping from the transmission breather tube of your KTM Motorcycle, correct the transmission oil level. This is caused by an excessive oil quantity in the transmission.
P
Patrick AndrewsSep 10, 2025
Why is my KTM 50 SX emitting white smoke?

KTM 50 SX Specifications

General

Displacement	49 cm³
Cooling System	Liquid cooled
Transmission	Single-speed automatic
Starter	Kickstarter
Front Brake	Disc brake
Rear Brake	Disc brake
Weight (without fuel)	41.5 kg
Seat Height	684 mm
Engine Type	Single cylinder, 2-stroke
Front Suspension	WP XACT 35 USD fork, Ø 35 mm
Rear Suspension	WP monoshock
Fuel Tank Capacity	2.3 liters

Summary

Means of Representation

Symbols Used

Explains the meaning of symbols used throughout the manual for clarity.

Formats Used

Details the typographical and other formats utilized in the manual's presentation.

Safety Advice and Precautions

Intended Use of Motorcycle

Defines the specific intended use and compliance of KTM sport motorcycles.

General Safety Instructions

Provides essential safety instructions for operating the vehicle safely. Read carefully.

Risk Degrees and Symbols

Explains different levels of risk and associated symbols used in the manual.

Protective Clothing

Emphasizes the importance of wearing protective clothing for rider safety and injury prevention.

Important Notes

Guarantee and Warranty Information

Details warranty conditions, service requirements, and voiding claims due to modifications.

Service and Maintenance

Emphasizes proper service, care, and tuning for optimal operation and longevity.

Spare Parts and Accessories

Recommends using approved parts and accessories installed by authorized workshops.

View of Vehicle Components

Left Front View of Motorcycle

Identifies key components visible from the left front view of the motorcycle.

Right Rear View of Motorcycle

Identifies key components visible from the right rear view of the motorcycle.

Serial Number Identification

Chassis Number Location

Shows the location where the chassis number is stamped on the vehicle.

Engine Number Location

Specifies where the engine number is stamped on the engine.

Vehicle Type Label

Indicates the location of the type label on the motorcycle's frame.

Motorcycle Controls

Hand Brake Lever Operation

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

Kill Switch Operation

Details the location and possible states of the kill switch for engine control.

Fuel Filler Cap Operation

Covers opening the fuel filler cap, including safety warnings about fuel.

Fuel Tap Operation

Describes the fuel tap's function and its open/closed states for fuel flow.

Preparing for Use

First Use Guidelines

Provides crucial advice for the initial use of the motorcycle, focusing on rider readiness and safety.

Engine Running-In Procedure

Details the recommended procedure for running in the engine to ensure longevity and performance.

Refueling the Motorcycle

Details the refueling process, including safety warnings and fuel type.

Riding Instructions

Pre-Ride Checks and Maintenance

Lists essential checks and maintenance tasks before operating the motorcycle.

Starting the Engine

Provides instructions and safety warnings for starting the motorcycle's engine.

Braking Techniques and Safety

Explains braking procedures, potential hazards, and adapting to conditions.

Motorcycle Transport

Provides instructions and safety notes for transporting the motorcycle securely.

Service Schedule and Maintenance

Scheduled Maintenance Intervals

Outlines the recommended service schedule based on operating hours and time intervals.

Chassis Tuning and Adjustments

Adjusting Shock Absorber Rebound Damping

Explains how to adjust the rebound damping on the shock absorber for optimal performance.

Checking Static Sag of Shock Absorber

Describes how to check the static sag of the shock absorber and its specifications.

Adjusting Shock Absorber Spring Preload

Provides instructions for adjusting the spring preload on the shock absorber.

Adjusting Seat Height

Guides the user on how to adjust the seat height of the motorcycle.

Chassis Service and Maintenance

Raising Motorcycle with Lift Stand

Instructions for safely raising the motorcycle using a lift stand.

Cleaning Fork Leg Dust Boots

Details how to clean the dust boots of the fork legs to prevent seal damage.

Checking Steering Head Bearing Play

Explains how to check for play in the steering head bearing.

Removing Air Filter

Procedure for removing the air filter for cleaning or replacement.

Brake System Operation and Maintenance

Checking Handbrake Lever Play

Details how to check the free play of the handbrake lever and its specifications.

Checking Brake Discs for Wear

Explains how to check the thickness and condition of the brake discs.

Checking Front Brake Fluid Level

Details how to check the front brake fluid level and related warnings.

Checking Rear Brake Fluid Level

Details how to check the rear brake fluid level and related warnings.

Wheels and Tires Maintenance

Removing Front Wheel

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

Checking Tire Condition

Guide on inspecting tire condition, tread depth, and age.

Checking Tire Air Pressure

Details how to check tire air pressure and recommended off-road values.

Cooling System Service

Checking Antifreeze and Coolant Level

Details how to check coolant level and antifreeze protection with safety warnings.

Draining Coolant

Instructions for draining the coolant, including safety warnings.

Refilling Coolant

Guide on refilling the cooling system with coolant and bleeding air.

Engine Tuning and Adjustments

Checking Throttle Cable Play

Details how to check the play in the throttle cable and related warnings.

Carburetor Idle Adjustment (50 SX)

Guidance on adjusting the idle speed and mixture for the 50 SX carburetor.

Adjusting the Clutch

Instructions for adjusting the clutch to achieve the correct slip speed.

Engine Service and Maintenance

Checking Engine Oil Level (50 SX Mini)

Details how to check the engine oil level in the oil tank for the 50 SX Mini.

Checking Gear Oil Level

Explains how to check the gear oil level.

Changing Gear Oil

Instructions for draining and changing the gear oil, with safety warnings.

Cleaning and Care

Cleaning the Motorcycle

Provides detailed instructions for cleaning the motorcycle, including safety precautions.

Motorcycle Storage

Long-Term Storage Procedures

Details actions to take when storing the motorcycle for an extended period.

Preparing for Use After Storage

Instructions on how to prepare the motorcycle for use after it has been stored.

Troubleshooting Guide

Engine Won't Start Troubleshooting

Addresses common causes and solutions when the engine fails to start.

Engine Overheating Troubleshooting

Diagnoses and resolves causes of engine overheating.

Engine Low Power Troubleshooting

Diagnoses and resolves issues causing the engine to have insufficient power.

Technical Data and Specifications

Engine Specifications

Provides detailed technical data for the engine, including displacement and lubrication.

Engine Tightening Torques

Lists specific torque values for various engine screws and nuts.

Tire Specifications

Details tire specifications, validity, and recommended sizes.

Chassis Tightening Torques

Lists specific torque values for chassis components.

Recommended Substances and Fluids

2-Stroke Engine Oil Recommendations

Specifies recommended 2-stroke engine oils and their standards.

Brake Fluid Specifications

Details recommended brake fluid types and compatibility.

Coolant and Antifreeze Recommendations

Provides information on recommended coolant types and mixture ratios.

Auxiliary Substances and Cleaners

Air Filter Cleaner Recommendations

Recommends specific cleaners for the air filter.

Chain Cleaner Recommendations

Specifies recommended cleaners for the drive chain.

Motorcycle Cleaner Recommendations

Recommends specific cleaners for the overall motorcycle.

Standards and Classifications

JASO FC Standard

Explains the JASO FC classification for 2-stroke engine oils.

SAE Viscosity Standard

Describes the SAE viscosity classification system for oils.

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KTM 50 SX SENIOR 2000