KTM 50 SX 2010 - User Manual

Questions and Answers

C
Clayton HowardAug 5, 2025
Why does my KTM Motorcycle engine have too little power?
- J
  James BoydAug 5, 2025
  If your KTM Motorcycle engine has too little power, several factors could be responsible. A fuel feed interruption could be the problem, so check the fuel tank breather and clean the fuel tap. A very dirty air filter can also cause this issue, so clean the air filter. Inspect the exhaust system for leaks or deformation and replace the glass fiber yarn filling in the main silencer if it's insufficient. The ignition system could be defective, so check the ignition coil and spark plug connector. Also, examine the diaphragm and reed valve housing for damage. Excessive wear might necessitate an engine overhaul. Lastly, an improperly adjusted clutch engagement speed can cause power loss, so check the clutch engagement speed.
P
Patrick BuckleyAug 13, 2025
What to do if my KTM Motorcycle engine stalls or is popping into the carburetor?
- A
  Adam KempAug 13, 2025
  If your KTM Motorcycle engine stalls or pops into the carburetor, it could be due to a few reasons. First, ensure the engine isn't running out of fuel by turning the knurled screw on the fuel tap all the way counterclockwise and filling up the fuel tank. Also, check for air leaks by inspecting the intake flange and carburetor for tightness. Clean the socket connector and treat it with contact spray if the socket connector or ignition coil is loose or oxidized.
G
Glenda BerryAug 21, 2025
Why does my KTM Motorcycle engine have no idle?
- K
  Karen WangAug 21, 2025
  If your KTM Motorcycle engine won't idle, there are several potential causes. The idling jet might be blocked, so check/set the carburetor components. Also, the adjusting screws on the carburetor could be distorted, so adjust the idle speed. A defective spark plug can also cause idling issues, so change the spark plug. Check the ignition coil and spark plug connector because the ignition system could be defective. Finally, if the carburetor is running over because the float needle is dirty or worn, check/set the carburetor components.
M
Matthew SextonOct 29, 2025
What to do if my KTM 50 SX 2010 engine turns but does not start?
- S
  Sandra DoyleOct 29, 2025
  If your KTM Motorcycle engine turns over but doesn't start, several factors could be at play. First, consider if it's an operating error and review the engine starting steps. If the motorcycle has been sitting unused for an extended period, old fuel in the float chamber might be the culprit; in this case, empty the carburetor float chamber. Check for any interruptions in the fuel feed, such as a blocked fuel tank breather or a dirty fuel tap. If the engine is flooded or the spark plug is oily/wet, clean and dry the spark plug, replacing it if necessary. Make sure that the spark plug electrode gap is properly adjusted to 0.60 mm (0.0236 in). Also, a fault in the ignition system, a short circuit in the cable harness, a defective kill switch, a loose or oxidized socket connector or ignition c...

Summary

Motorcycle Operation

Starting the engine

Front Fork and Triple Clamp Service

Removing the fork legs

Step-by-step guide for safely removing the front fork legs from the motorcycle.

Checking the fork legs

Instructions for inspecting inner tubes, outer tubes, and springs for damage or wear.

Removing the lower triple clamp

Shock Absorber and Swingarm Service

Adjusting the rebound damping of the shock absorber

How to adjust the shock absorber's rebound damping for desired ride characteristics.

Adjusting the spring preload of the shock absorber

Steps to adjust the shock absorber spring preload for proper sag settings.

Servicing shock absorber

Air Filter Service

Front Wheel Service

Removing front wheel

Step-by-step instructions for safely removing the front wheel.

Installing the front wheel

Procedure for correctly installing the front wheel.

Rear Wheel Service

Removing rear wheel

Step-by-step guide for safely removing the rear wheel.

Installing the rear wheel

Procedure for correctly installing the rear wheel.

Cleaning the chain

Checking the chain tension

Adjusting chain tension

Brake System Service

Checking the front brake fluid level

Procedure for checking the front brake fluid reservoir level.

Checking the front brake linings

Inspection of front brake linings for wear and damage.

Checking the rear brake fluid level

Procedure for checking the rear brake fluid reservoir level.

Checking the rear brake linings

Inspection of rear brake linings for wear and damage.

Engine Service

Removing the engine

Step-by-step guide for safely removing the engine from the frame.

Installing the engine

Procedure for correctly installing the engine back into the frame.

Removing the cylinder head

Instructions for disassembling and removing the cylinder head.

Removing the piston

Procedure for removing the piston from the cylinder.

Installing the piston

Steps for correctly installing the piston into the cylinder.

Installing the cylinder

Procedure for fitting the cylinder onto the engine block.

Engine - Work on Individual Parts

Changing the conrod bearing

Procedure for replacing the conrod bearing.

Checking the crankshaft run-out on the bearing pin

Method for checking crankshaft run-out to ensure alignment.

Checking;measuring clutch

Engine - Assembly

Installing the crankshaft

Procedure for installing the crankshaft into the engine case.

Installing the left engine case

Steps for fitting the left section of the engine case.

Carburetor Service

Removing the carburetor (50 SX)

Instructions for safely removing the carburetor from the 50 SX model.

Installing the carburetor (50 SX)

Procedure for correctly installing the carburetor on the 50 SX.

Clutch Service

Removing the centrifugal force clutch

Step-by-step guide for disassembling the centrifugal clutch.

Checking clutch engagement speed

Procedure for measuring and verifying the clutch engagement speed.

Adjust the clutch engagement speed

Water Pump and Cooling System

Lubrication System Service

Ignition System Service

Checking the ignition system

Troubleshooting

Engine turns but does not start

Diagnosing causes and solutions when the engine fails to start.

Engine has no idle

Troubleshooting steps for an engine that does not maintain idle speed.

Engine overheats

Identifying and resolving issues causing the engine to overheat.

Technical Data - Engine

Capacity - gear oil

Technical Data - Carburetor

50 SX Carburetor Specifications

50 SX Mini Carburetor Specifications

Technical Data - Chassis

Technical Data - Fork

50 SX Fork Specifications

50 SX Mini Fork Specifications

Technical Data - Shock Absorber

50 SX Shock Absorber Specifications

50 SX Mini Shock Absorber Specifications

Service Schedule

Important maintenance work for authorized KTM workshop

List of maintenance tasks recommended for authorized KTM workshops.

Wiring Diagram

Wiring diagram

Substances

Special Tools

KTM 50 SX 2010 Specifications

General

Front Brake	Disc brake
Rear Brake	Disc brake
Cooling System	Liquid cooled
Fuel Tank Capacity	2.3 L
Starter	Kickstarter
Rear Brake Diameter	160 mm
Engine Type	Single-cylinder, 2-stroke
Displacement	49 cc
Bore x Stroke	39.5 mm x 40.0 mm
Rear Suspension	Monoshock
Frame	Steel