🏷️ Basic Information

Make:

KTM

Model:

50 SX JUNIOR

Model Variant:

JUNIOR

Market:

USA

Year:

2008

Product Code Identifier:

EXPLODED VIEW PARTS LIST

👋 Introduction

Vehicle Segment:

Entry-level youth motocross motorcycle

Target Audience:

Young riders learning the fundamentals of motocross and off-road riding.

Key Competitors:

Husqvarna TC 50, Cobra CX50, Yamaha YZ50F (though YZ50F is 4-stroke and older).

Youth Oriented Design:

Scaled-down ergonomics and controls for junior riders.

Performance Focus:

Designed for competitive motocross use, emphasizing power and handling.

Durability:

Built with robust components suitable for the rigors of off-road riding.

📋 Manual Details

Manual Type:

Parts List / Exploded View

Coverage Scope:

Engine Components

Estimated Pages:

Variable (dependent on specific parts list format, typically 20-50 pages for a focused list)

Manual Format Description:

Diagrammatic illustration of engine components with corresponding part numbers for identification and ordering.

Language:

English

Digital Format:

PDF (likely)

📖 Manual Coverage

Engine Assembly:

Complete breakdown of the 50cc engine assembly, including all internal and external parts.

Carburetor Assembly:

Detailed view of carburetor components and their arrangement.

Ignition System Components:

Identification of spark plug, coil, and related ignition parts.

Exhaust System Components:

Illustration of exhaust pipe and silencer components.

Cooling System Components:

Identification of any relevant cooling system parts, though likely air-cooled.

Air Filter Assembly:

Breakdown of the air intake and filter housing.

Clutch Assembly:

Exploded view of the centrifugal clutch mechanism.

Drive Train Components:

Identification of sprockets and chain components.

Part Identification:

Precise identification of every individual component within the engine assembly.

Part Number Lookup:

Provides official KTM part numbers for ordering replacement parts.

Assembly Guidance:

Visual guidance on the correct placement and order of components during reassembly.

Depth Level:

Component Identification & Replacement

Diagnostic Assistance:

Indirectly aids in diagnosing issues by clearly showing component relationships.

Repair Assistance:

Essential for identifying correct parts for repairs and understanding how they fit together.

📊 Manual Specifications

File Type:

Digital (PDF likely)

Searchability:

Typically searchable by text within the PDF for part names or numbers.

Print Readability:

High, designed for clear viewing of diagrams and part numbers.

Binding Method:

N/A (Digital Format)

Paper Quality:

N/A (Digital Format)

⚙️ Engine Specifications

Engine Type:

Single-cylinder, 2-stroke

Displacement:

49 cc (3.0 cu in)

Bore X Stroke:

39.5 x 40 mm (approximate, often not specified in basic parts lists)

Cooling System:

Air-cooled

Lubrication:

Pre-mix (typically 1:50 ratio of quality 2-stroke oil to gasoline)

Horsepower:

Approximately 8.0 - 9.0 HP (subject to specific tuning and conditions)

Torque:

Not typically quoted for this class, but optimized for low-end grunt.

Carburetor Model:

Dell'Orto PHVA 12 (common, but can vary slightly)

Fuel Type:

Unleaded gasoline (minimum 91 octane recommended)

Fuel Delivery:

Carburetor with gravity feed

🔧 Transmission

Transmission Type:

Automatic (Centrifugal Clutch)

Optional Transmission:

N/A

Clutch Type:

Automatic centrifugal clutch, requiring no rider input for gear changes.

Drive:

Chain drive

📐 Dimensions

Wheelbase:

Approx. 1040 mm (40.9 in)

Seat Height:

Approx. 560 mm (22.0 in)

Ground Clearance:

Approx. 160 mm (6.3 in)

Dry Weight:

Approx. 40 kg (88.2 lbs)

Fuel Tank Capacity:

Approx. 2.3 liters (0.61 US gal)

🛡️ Safety Features

Safety Certification:

Meets EPA emissions standards for off-road use. Not street legal.

Brakes Front:

Hydraulic disc brake with wave rotor, 4-piston caliper (specific model may vary, e.g., Formula).

Brakes Rear:

Hydraulic disc brake with wave rotor, 2-piston caliper (specific model may vary, e.g., Formula).

Suspension Front:

WP Upside-Down (USD) fork, approx. 35mm diameter, 100mm travel (specifics can vary).

Suspension Rear:

WP Monoshock, approx. 100mm travel (specifics can vary).

Handlebars:

Youth-sized handlebars with handguards.

Seat:

Contoured seat for stability.

💡 Technology Features

Infotainment System:

N/A (Basic motocross competition machine, no infotainment features).

Driver Assistance Systems:

N/A (No electronic driver assistance systems).

Connectivity Features:

N/A (No connectivity features).

🔧 Maintenance

Air Filter Cleaning:

Clean after every few rides, depending on conditions. Replace as needed.

Spark Plug Replacement:

Inspect and clean regularly. Replace as per engine manual, typically every 20-40 hours of use.

Chain Lubrication:

Lubricate chain before every ride and after washing.

Gearbox Oil Change:

Refer to the service manual. Typically every 10-20 hours of use for clutch-integrated gearbox oil.

2 Stroke Oil:

High-quality synthetic 2-stroke oil for racing applications (e.g., Motorex, Castrol TTS). Mix ratio typically 1:50.

Gearbox Oil:

Specific KTM gearbox oil or equivalent SAE 10W/50 API SG or higher (refer to service manual for exact specification).

Brake Fluid:

DOT 4 Hydraulic Brake Fluid.

Carburetor Clogging:

Common in small 2-strokes if fuel quality is poor or bike sits with fuel in the carb. Requires regular cleaning.

Clutch Wear:

Centrifugal clutches can wear over time, especially with aggressive riding. Springs and shoes may need replacement.

Air Filter Maintenance:

Crucial for engine longevity. Neglecting it leads to premature wear.

📚 Vehicle History

Ktm Legacy:

KTM has a long-standing reputation for producing high-performance off-road and motocross motorcycles.

50Sx Lineage:

The 50 SX line has been a cornerstone for KTM's junior motocross program, evolving with component updates and chassis refinements over the years.

Manufacturing Origin:

Austria (KTM AG)

🏆 Awards & Recognition

Motocross Awards:

While specific model year awards might be rare, the KTM 50 SX has consistently been a benchmark in the junior motocross class, earning numerous informal recognitions from parents, trainers, and junior riders for its performance and suitability as a first competition bike.

Industry Perception:

Highly regarded as a quality entry-level motocross machine.