This manual covers the TZ125G1, a performance racing motorcycle produced from 1990 to 2005. Engineered for track days and club racing, the TZ125 is renowned for its high-revving, liquid-cooled two-stroke engine, lightweight race-bred chassis, and exceptional handling capabilities. Its design emphasizes extensive tuning potential and a focus on delivering peak performance in competitive environments, building on a rich heritage in Grand Prix racing. This comprehensive workshop service and repair manual provides detailed guidance for maintaining and repairing your TZ125G1. It covers all essential systems, including engine overhaul, transmission, chassis, electrical systems, and braking. The manual offers step-by-step instructions for periodic maintenance, troubleshooting common faults, and complete component repair and overhaul procedures, making it an indispensable resource for owners and technicians seeking to ensure optimal performance and longevity. 🏷️ Basic Information Identification Make: Yamaha Model: TZ125G1 Production Years Covered: 1990-2005 Codes Manual Code: Not Specified 👋 Introduction Market Position Segment: Performance Racing Motorcycle Usage: Track days, club racing, high-performance riding. Competitive Analysis Competitors 125Cc Class: Honda RS125, Aprilia RS 125 (though TZ is more track-focused). Key Features Engine Type: High-revving two-stroke, liquid-cooled, single-cylinder. Chassis Design: Lightweight, race-bred chassis for exceptional handling. Tuning Potential: Designed for extensive tuning and modification for racing. Suspension: High-performance adjustable front forks and rear shock absorber. 📋 Manual Details Coverage Areas Primary Coverage: Workshop Service and Repair Secondary Coverage: Periodic Maintenance, Troubleshooting, Overhaul Procedures, Wiring Diagrams Page Count Estimated Page Count: Hundreds (as per description) Manual Type Type: Workshop Service Manual / Repair Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine System: Complete engine overhaul, tuning, carburetor, ignition system, cooling system (if applicable), lubrication. Transmission System: Gearbox inspection, maintenance, repair, clutch operation. Chassis System: Frame inspection, suspension (front and rear), steering, wheels, tires. Electrical System: Wiring diagrams, lighting, ignition, charging system, battery, instrumentation. Braking System: Brake caliper, master cylinder, brake lines, fluid replacement, adjustments. Bodywork And Trim: Fairings, body panels, seat, controls, exhaust system. Carburetor System: Detailed breakdown, adjustment, cleaning, and jetting information for Mikuni carburetors. Fuel System: Fuel tank, lines, fuel cock, carburetor. Procedures Included Maintenance: Regular scheduled maintenance, oil changes, filter replacements, chain adjustment, spark plug service. Troubleshooting: Diagnostic procedures for common and uncommon faults, symptom-based solutions. Repair: Step-by-step instructions for component disassembly, repair, and reassembly. Overhaul: Detailed procedures for engine, gearbox, and other major component rebuilds. Engine Tuning: Information on port timing, exhaust modifications, and ignition curve adjustments. Diagnostics: Systematic diagnosis of electrical and mechanical faults. Technical Depth Depth: Comprehensive, suitable for professional technicians and advanced DIY enthusiasts. Detail Level: Detailed diagrams, torque specifications, clearances, adjustment procedures. 📊 Manual Specifications File Format Format: PDF Requirements: Adobe PDF Reader, WinRAR Compatibility: All Versions of Windows & Mac Print Quality Printability: Full Printable Zoom Capability: YES (Zoom IN/OUT) Binding Type Binding: Digital Download (Printable) Paper Type Paper Type Suggestion: Not Applicable (Digital) ⚙️ Engine Specifications Primary Engine Engine Type: Liquid-cooled, 2-stroke, reed valve induction, single-cylinder Bore X Stroke: Typically around 56 mm x 50.7 mm (subject to specific TZ125 variant evolution). Displacement: 124 cc Compression Ratio: Variable, typically high for racing (e.g., 10.0:1 or higher). Cooling System: Liquid-cooled Performance Horsepower: Estimated 30-40+ HP (depending on year, tuning, and exhaust). Torque: Not typically the primary focus for this class, but significant at high RPM. Fuel System Carburetor: Mikuni VM series (e.g., VM28SS or similar high-performance variant). Fuel Type: High-octane gasoline, often mixed with two-stroke oil. Ignition System Ignition: CDI (Capacitor Discharge Ignition), often with adjustable timing. 🔧 Transmission Standard Type: 6-speed constant mesh Optional Features: Close-ratio gear sets for optimal track performance. Features Clutch Type: Wet, multi-plate 📐 Dimensions Exterior Length: Approximately 1915 mm (varies slightly by year). Width: Approximately 690 mm (varies slightly by year). Height: Approximately 1050 mm (varies slightly by year). Weights Dry Weight: Around 90-95 kg (highly dependent on year and specific race configuration). Fuel Capacity: Approximately 9.5 - 10.5 Liters. 🛡️ Safety Features Ratings Classification: Competition Motorcycle (not street legal in most configurations). Active Features Handling: Designed for extreme lean angles and precise control. Passive Features Frame Construction: Lightweight aluminum alloy frame for rigidity and mass centralization. 💡 Technology Features Infotainment Features: Basic instrumentation focused on essential riding information (tachometer, speedometer, temperature). Driver Assistance Features: None (This is a pure racing machine). Connectivity Features: None. 🔧 Maintenance Service Intervals Oil Change: After every few race sessions or as specified for track use (pre-mix or oil injection system). Spark Plug: Regularly inspected and replaced based on plug type and usage. Chain Adjustment: Frequent checks and adjustments required due to high performance. Engine Rebuild: Typically performed after a set number of race hours or performance degradation. Fluid Specifications Coolant: High-quality motorcycle-specific coolant with anti-corrosion additives. Transmission Oil: Yamaha's recommended 2-stroke transmission oil or equivalent. Brake Fluid: DOT 4 or DOT 5.1, depending on specific brake system requirements. Premix...