KTM 450 SX ATV User Manual (English)

Questions and Answers:

J
Jacqueline HallJul 28, 2025
Why won't my KTM Offroad Vehicle engine start?
- V
  vargasmarkJul 28, 2025
  If your KTM Offroad Vehicle's engine turns over but doesn't start, several factors could be at play. Start by ensuring you're following the correct starting procedure. A common issue is fuel supply interruption; check the fuel tank breather and clean the fuel tap. Inspect and adjust the carburetor components as well. Also, a spark plug that's oily or wet can prevent ignition; clean and dry it, or replace if needed. Make sure the spark plug electrode gap is correctly set to 0.7 mm (0.028 in). Finally, inspect the kill switch/emergency OFF switch wiring and electrical system for faults.
K
Katherine CastanedaAug 2, 2025
What to do if KTM Offroad Vehicle engine turns but does not start and spark plug is oily?
- S
  Stephanie TerrellAug 2, 2025
  If the engine of your KTM Offroad Vehicle turns but fails to start, and the spark plug is oily or wet, you should clean and dry the spark plug. If cleaning doesn't resolve the issue, consider replacing the spark plug.
M
Michael WilsonAug 9, 2025
What to do if KTM Offroad Vehicle engine turns but does not start and socket connector is oxidized?
- L
  lisamartinAug 9, 2025
  If your KTM Offroad Vehicle engine turns but does not start, and you suspect the socket connector of the CDI control device, pulse generator or ignition coil is oxidized, clean the plug-in connector and treat it with contact spray.
A
arthur02Aug 14, 2025
What to do if KTM 450 SX ATV engine turns but does not start and kill switch is faulty?
- A
  amorrisAug 14, 2025
  If your KTM Offroad Vehicle's engine turns over but fails to start, and you suspect the kill switch/emergency OFF switch with rip cord is faulty, check the wiring harness with a visual inspection and check the electrical system.
D
Debbie HicksAug 20, 2025
Why KTM 450 SX ATV engine turns but does not start when throttle lever activated?
- D
  Diana PearsonAug 20, 2025
  If your KTM Offroad Vehicle's engine turns but doesn't start, ensure that you are not activating the throttle lever during the starting procedure. Refer to the starting instructions for the correct procedure.

KTM 450 SX ATV Specifications

General

Brand	KTM
Model	450 SX ATV
Category	Offroad Vehicle
Language	English

Summary

IMPORTANT INFORMATION

Use definition and maintenance basics

Defines ATV use and stresses the importance of proper maintenance for longevity.

Handlebar and Safety Controls

Hand brake, parking brake, and kill switch

Details hand brake, parking brake, and kill switch functions for safety and control.

GENERAL TIPS AND HINTS ON PUTTING INTO OPERATION

First-use advice and safety

Provides crucial advice for new riders, including safety warnings and training recommendations.

Initial Operation Guidance

Engine break-in procedure

Guidelines for the engine's running-in phase to ensure proper break-in and longevity.

RIDING INSTRUCTIONS

Pre-ride checks and starting procedures

Lists essential pre-ride checks and detailed engine starting instructions.

Riding Techniques

Shifting, braking, and cornering

Explains gear shifting, braking, and cornering techniques with safety advice.

Basic Riding Operation

Normal riding and stopping

General guidance on riding posture, operation, and stopping the engine.

Riding on Slopes

Uphill and downhill riding techniques

Instructions and warnings for safely riding uphill and downhill, including slope angles.

Riding on Slopes and Water

Riding across slopes and through water

Advice on riding across slopes and through water, with safety precautions.

Parking and Refueling

Safe parking and refueling procedures

Procedures for parking and detailed safety warnings for refueling the vehicle.

SERVICE SCHEDULE

Workshop maintenance tasks schedule

Rider Maintenance Schedule

Routine checks and rider maintenance tasks

Routine checks and maintenance tasks the rider can perform themselves.

MAINTENANCE ON CHASSIS AND ENGINE

Vehicle lifting and chassis settings

Shock Absorber Adjustments

Front shock absorber damping adjustments

Guide on adjusting front shock absorber compression and rebound damping.

Front Shock Absorber Adjustments

Front spring preload adjustment

Steps to adjust the spring preload on the front shock absorber.

Rear Shock Absorber Adjustments

Rear shock absorber damping adjustments

Guide on adjusting rear shock absorber compression and rebound damping.

Rear spring preload adjustment

Steps to adjust the spring preload on the rear shock absorber.

Chassis Alignment and Suspension

Installing rear shock and checking toe alignment

Chassis Alignment Adjustments

Adjusting front wheel toe alignment

Checking and adjusting wheel camber

Chain Maintenance Procedures

Cleaning and tensioning the drive chain

Chain Tension Adjustment

Adjusting drive chain tension

Wheel and Brake System Checks

Greasing rear eccentric element and brake disc inspection

Brake Lever and Fluid Checks

Adjusting hand brake lever and checking front fluid

Adjusting hand brake lever position and checking front brake fluid level.

Front Brake Linings Check

Checking front brake lining thickness

Rear Brake Fluid and Lever Checks

Checking rear brake fluid level

Instructions for checking the rear brake fluid level and identifying potential issues.

Rear Brake Fluid Service

Adding rear brake fluid

Step-by-step guide on how to add rear brake fluid, including safety precautions.

Rear Brake Linings Check

Checking rear brake lining thickness

Ignition System Adjustments

Ignition curve plug connection and change

Air Filter Service

Removing the air filter

Installing the air filter

Air Filter Cleaning

Cleaning the air filter

Cooling System Checks

Checking antifreeze and coolant level

How to check coolant antifreeze protection and level, with safety warnings.

Checking coolant level

How to check the coolant level in the radiator, with safety warnings.

Coolant Draining Procedure

Draining the coolant

Cooling System Filling Procedure

Filling and bleeding cooling system

Instructions for filling the cooling system with coolant and bleeding air, with safety warnings.

Carburetor Idle Adjustment

Adjusting carburetor idle speed and mixture

Detailed steps for adjusting the carburetor idle speed and mixture.

Carburetor Idle Speed Adjustment

Adjusting idle speed

Steps to fine-tune the engine idle speed for optimal performance.

Engine Oil and Filter Service

Changing engine oil, filter, and oil screen

Comprehensive guide to changing engine oil, oil filter, and cleaning the oil screen.

Engine Oil Screen Cleaning

Cleaning the oil screen

Engine Oil Filter Service

Removing and installing oil filter

Instructions for safely removing and correctly installing the engine oil filter.

Engine Oil Refill

Filling up with engine oil

Guide for refilling the engine with the correct type and amount of oil.

Adding engine oil

Instructions for adding engine oil, including temperature-specific recommendations.

TROUBLESHOOTING

Engine starting problems

Lists possible causes and actions for engine starting issues.

Engine Performance Issues

Starter, acceleration, and idle problems

Possible causes and actions for starter, acceleration, and idle issues.

Engine Operation Problems

Stalling, backfiring, and overheating

Addresses engine stalling, backfiring, and overheating problems with potential fixes.

Engine and Battery Issues

Power loss, oil consumption, battery problems

Diagnoses for lack of power, oil consumption, and battery problems.

STORAGE PROCEDURES

Preparing vehicle for storage

Post-Storage Vehicle Operation

Putting vehicle into operation after storage

TECHNICAL DATA - ENGINE

ENGINE TIGHTENING TORQUES

CARBURETOR TECHNICAL DATA

CHASSIS TECHNICAL DATA

FRONT SHOCK ABSORBER DATA

REAR SHOCK ABSORBER DATA

CHASSIS TIGHTENING TORQUES

OPERATING SUBSTANCES

Brake fluid and coolant specifications

Engine oil specifications

Recommendations for SAE 10W/50 and 5W/40 engine oils.

Related product manuals