Segment:
Entry-level to mid-level sportbike/naked bike segment, offering accessible performance and styling.
Target Audience:
New riders, budget-conscious enthusiasts, and owners seeking to perform their own maintenance and repairs.
Competitors:
Kawasaki Ninja 250/300, Honda CBR250R/300R, Yamaha R25/R3 (depending on specific market and year comparison).
Manual Value Proposition:
Provides comprehensive technical data and procedures to empower owners and independent workshops for effective maintenance and repair, reducing reliance on expensive dealership services.
Accessibility:
Instant download in PDF format ensures immediate access to crucial repair information.
Coverage Scope:
All repairs, service, maintenance, adjustments, overhauls, troubleshooting, and specifications
Estimated Page Count:
Detailed, comprehensive (specific number not provided but implied to be extensive for workshop use)
Type:
Workshop Service Repair Manual
Engine:
Engine assembly, disassembly, internal components, lubrication system, cooling system, ignition system, fuel system, carburetor/fuel injection (depending on model variant).
Transmission:
Gearbox operation, clutch system, shift mechanism, transmission fluid specifications.
Electrical System:
Wiring diagrams, lighting system, starting system, charging system, battery, ignition switch, sensors, ECU (if applicable).
Chassis And Suspension:
Front fork assembly and adjustments, rear shock absorber and linkage, swingarm, steering system, bearings.
Braking System:
Front and rear brake systems (disc brakes), brake fluid, hydraulic lines, calipers, master cylinders, bleeding procedures.
Fuel System:
Fuel tank, fuel lines, petcock, fuel pump (if applicable), carburetor tuning and cleaning (for GT125/GT250), fuel injection system diagnostics (for later GT250i models).
Exhaust System:
Exhaust pipe removal, installation, and gasket replacement.
Wheels And Tires:
Wheel removal and installation, tire pressure specifications, bearing maintenance.
Bodywork And Trim:
Fairing removal and installation, seat, fenders, fuel tank cover.
Maintenance:
Regular scheduled maintenance, oil changes, filter replacements, chain adjustment, lubrication, spark plug replacement, brake checks, fluid level checks.
Repair:
Detailed step-by-step repair instructions for all major systems and components, including engine internals, transmission, suspension, brakes, and electrical faults.
Troubleshooting:
Diagnostic procedures for common problems, identification of causes, and recommended solutions.
Disassembly Reassembly:
Complete instructions for taking apart and putting back together all vehicle components and systems.
Adjustments:
Precise instructions for adjusting critical components like clutch, brakes, suspension, and carburetor idle speed.
Overhauls:
Comprehensive guidance for complete engine rebuilds and major system overhauls.
Depth:
Comprehensive: from basic user maintenance to advanced diagnostic and repair procedures suitable for professional mechanics and experienced DIY enthusiasts.
Diagnostic Capability:
High, including detailed troubleshooting guides and symptom-based problem solving.
Diagrammatic Representation:
Excellent, featuring easy-to-understand exploded views and detailed diagrams for component identification and assembly.
File Type:
PDF (Portable Document Format)
Compatibility:
PC & Mac compatible (Windows 95, 98, 2000, NT, XP, Vista, 7, 8, etc.)
Searchability:
Likely searchable text-based PDF, allowing for quick information retrieval.
Print Readability:
Designed for clarity and ease of reading, suitable for printing specific sections or the entire manual.
Binding:
Not applicable (Digital Download)
Paper Quality:
Not applicable (Digital Download)
Engine Type:
V-twin, 4-stroke, liquid-cooled (common configuration)
Displacement:
124cc (approx.)
Bore X Stroke:
Variable, typically around 49.0 x 66.0 mm (check specific model variant)
Compression Ratio:
Variable, often around 10.0:1 (check specific model variant)
Horsepower:
Approximately 15-17 HP (check specific model variant)
Torque:
Approximately 10-12 Nm (check specific model variant)
Engine Type:
V-twin, 4-stroke, liquid-cooled
Displacement:
249cc (approx.)
Bore X Stroke:
Variable, typically around 57.0 x 49.0 mm (check specific model variant)
Compression Ratio:
Variable, often around 10.0:1 (check specific model variant)
Horsepower:
Approximately 28-30 HP (check specific model variant)
Torque:
Approximately 22-24 Nm (check specific model variant)
Fuel Delivery Gt125:
Carburetor (dual Keihin or similar, depending on year)
Fuel Delivery Gt250:
Carburetor (dual Keihin or similar, later models GT250i use Fuel Injection)
Fuel Type:
Unleaded gasoline
Cooling Method:
Liquid-cooled
Ignition Type:
CDI (Capacitor Discharge Ignition) or Electronic Ignition
Safety Ratings:
Not applicable (Motorcycle safety is typically assessed through regulatory standards and independent testing agencies, not standardized ratings like cars).
Braking System Type:
Disc brakes (front and rear), hydraulic actuation.
ABS:
Optional on some later GT250 models, not standard on most 2002 onwards models covered.
Lighting:
Halogen headlight, LED taillight (on some later models), turn signals.
Frame Construction:
Steel diamond frame or trellis frame (depending on specific model variant).
Oil Change Interval:
Typically every 3,000-6,000 km or 6-12 months (refer to manual for specific mileage/time interval and conditions).
Spark Plug Replacement:
Every 10,000-15,000 km (specific plug type and gap to be confirmed in manual).
Chain Adjustment:
Regularly check and adjust slack every 1,000-2,000 km, lubricate frequently.
Valve Clearance Check:
Typically at 10,000-20,000 km intervals (critical for engine health, refer to manual).
Engine Oil Type:
JASO MA certified motorcycle oil, SAE 10W-40 or 10W-50 (check manual for precise viscosity and API rating, e.g., Yamalube, Motul 5100).
Engine Oil Capacity:
Approximately 1.5 - 2.0 Liters (including filter, check manual for exact quantity).
Coolant Type:
Ethylene glycol-based antifreeze/coolant, mixed 50/50 with distilled water.
Brake Fluid Type:
DOT 3 or DOT 4 (check manual for precise specification).
Common Wear Items:
Clutch plates, chain and sprockets, brake pads, fork seals, wheel bearings.
Carburetor Issues:
Clogged jets, idle instability, off-idle hesitation, particularly if fuel is left in the system for extended periods without stabilizer. Regular cleaning and synchronization are key.
Electrical Gremlins:
Can sometimes arise from aging connectors or poor grounds. The manual's wiring diagrams are essential for diagnosing these.
Cooling System Maintenance:
Ensuring proper coolant levels and regular flushing is vital to prevent overheating, especially in the V-twin configuration.
Manufacturer:
Hyosung (South Korea)
Manufacturer Background:
Hyosung Motors & Heavy Industries, part of the Hyosung Group, known for its diverse manufacturing capabilities including motorcycles.
Gt125 Development:
Evolved from earlier Hyosung 125cc models, focusing on a V-twin engine for a unique selling proposition in its class.
Gt250 Development:
Introduced as a significant step up from the 125cc, adopting a larger V-twin engine and refined styling, with updates including fuel injection on later iterations (GT250i).
Production Period:
Since 2002, with continuous updates and variants introduced.
Manufacturing Locations:
South Korea
