The Yamaha DT125R, produced from 1988 to 2002, is a versatile dual-sport motorcycle celebrated for its robust engineering and reliable performance. Known for its 2-stroke, liquid-cooled engine with the innovative Yamaha Power Valve System (YPVS), the DT125R offers engaging power delivery suitable for both on-road commuting and off-road adventures. Its design emphasizes durability and trail capability, making it a favored choice for riders seeking a capable and enduring machine. Yamaha's heritage in motorcycle manufacturing further underscores the quality and engineering prowess found in this iconic model. This factory service and repair manual provides comprehensive guidance for the Yamaha DT125R (3FW) generation covering production years 1988-2002. It details complete factory-level repair procedures, engine fault diagnosis, electrical system troubleshooting, routine maintenance, and engine tuning. The manual includes step-by-step repair instructions for all major components, detailed electrical wiring diagrams, and advanced troubleshooting for common issues. It is designed to assist owners, mechanics, and technicians in effectively maintaining, repairing, and restoring the DT125R, ensuring its longevity and optimal performance through clear, illustrated instructions. 🏷️ Basic Information Identification Make: Yamaha Model: DT125R Generation: DT125R (3FW) Production Years Covered: 1988-2002 👋 Introduction Market Position Target Audience: Yamaha DT125R owners, DIY mechanics, restoration enthusiasts Competitive Analysis Value Proposition: Provides professional-level repair knowledge, enabling significant cost savings on labor ($50-$60/hour) Key Features Completeness: Covers every detail for repair, maintenance, rebuilding, refurbishing, and restoration Ease Of Use: User-friendly navigation, printable pages, numbered instructions, clear illustrations Authenticity: Actual Genuine Factory Service Manual 📋 Manual Details Coverage Areas Primary Coverage: Complete Factory Service & Repair Diagnostic Coverage: Engine Fault Diagnosis, Electrical System Troubleshooting Maintenance Coverage: Routine Maintenance, Scheduled Service Repair Coverage: Step-by-step repair procedures for all major components Tuning Coverage: Engine Tuning and Performance Adjustments Wiring Diagrams: Detailed Electrical Wiring Diagrams Page Count Estimated Pages: Hundreds of pages (actual number not specified, but implied comprehensive) Manual Type Type: Official Factory Service Repair Manual Origin: Genuine Factory Manuals (Not 3rd Party) Language Language: English Format Delivery Format: PDF Download File Format: PDF Compatibility: Windows and Mac OS Portability: Printable (entire manual or selected pages) Searchability: Searchable PDF (allows quick information retrieval) 📖 Manual Coverage Systems Covered General Information: Included Fuel System: Included (Carburetor, fuel lines, fuel tank) Cooling System: Included (if applicable to the DT125R variants within the year range) Engine Top End: Included (Cylinder, piston, cylinder head, exhaust valve timing if applicable) Clutch: Included (Clutch operation, maintenance, adjustment) Engine Lubrication: Included (Oil injection system, oil pump) Engine Removal Installation: Included (Detailed procedures) Crankshaft Transmission: Included (Gearbox, crankshaft, bearings, seals) Wheels Tires: Included (Wheel bearing maintenance, tire changes, wheel balancing) Final Drive: Included (Chain and sprockets maintenance, adjustment) Brakes: Included (Front and rear brake systems, hydraulic/mechanical, fluid replacement) Suspension: Included (Front forks, rear shock absorber, linkage maintenance) Steering: Included (Handlebar, steering stem, bearings) Frame: Included (Chassis inspection, maintenance) Electrical System: Included (Ignition, lighting, charging system, battery, wiring harnesses) Appendix: Included (Potentially for specifications or reference data) Procedures Included Troubleshooting: Advanced troubleshooting guide for common and complex issues Diagnostics: Engine fault symptom diagnosis, part testing techniques Routine Maintenance: Oil changes, filter replacements, chain lubrication, general checks Component Rebuild: Engine top-end rebuild, transmission overhaul, suspension fork rebuild Electrical Repair: Wiring harness repair, component testing, diagnostic procedures Assembly Disassembly: Step-by-step guides for engine, chassis, and component removal/installation Technical Advice: Tips for owner-mechanic communication, identifying quality work Technical Depth Depth: Comprehensive Factory Level (suitable for technicians and advanced DIYers) Detail Level: Detailed substeps, notes, cautions, warnings, numbered instructions Illustrations: Detailed illustrations, drawings, and photos Illustrations Detail: Enlarged inset views for critical component examination 📊 Manual Specifications File Format Quality: High Resolution Print Quality Printability: Fully Printable (unrestricted) Binding Type Binding: N/A (Digital PDF Download) Paper Type Paper Type: N/A (Digital PDF Download) ⚙️ Engine Specifications Primary Engine Engine Type: 2-stroke, Single Cylinder, Reed Valve Induction, YPVS (Yamaha Power Valve System) - Common for many DT125R models Displacement: Approximately 123-124cc (specific variant dependent) Cooling: Liquid-cooled (typical for DT125R, though air-cooled variants might exist in early years) Performance Horsepower: Typically in the range of 20-26 HP depending on year and specific tuning (manual will detail exact specs) Torque: Varies, but typically around 1.7-2.0 kgf-m (manual will provide precise figures) Fuel System Carburetor: Mikuni VM24 or similar (manual will specify exact model and jetting) Fuel Type: Unleaded gasoline, typically with 2-stroke oil premix (or via autolube system) 🔧 Transmission Standard Transmission Type: 6-speed constant mesh Optional Optional Transmission: N/A (Standard for the model) Features Clutch Type: Wet, multi-plate 📐 Dimensions Exterior Length: Varies by specific sub-model, but typically around 2100-2200 mm Width: Varies by specific sub-model, but typically around 770-850 mm Height: Varies by specific sub-model, but typically around 1150-1250 mm Weights Dry Weight: Approximately 110-120 kg (depending on model variant and equipment) 🛡️ Safety Features Ratings Safety Ratings: N/A (Motorcycle, not subject to automotive crash ratings) Active Features...