The Yamaha DT125R, produced between 1987 and 1988, is a versatile dual-sport motorcycle renowned for its lightweight, agile handling and reliable 2-stroke, liquid-cooled 124cc engine. Building on a legacy in motorcycle manufacturing, the DT series has a history of popularizing off-road and dual-sport riding. This particular model offers a compelling blend of performance and practicality, making it a popular choice for both entry-level riders and experienced enthusiasts venturing onto trails and light off-road terrain. Its engineering emphasizes mechanical simplicity and rider control, reflecting a design philosophy focused on dependable performance. This comprehensive workshop service repair manual provides detailed guidance for maintaining and repairing the Yamaha DT125R models from 1987 and 1988. It covers a wide array of systems, including the engine's mechanical and electrical components, fuel and emission control systems, suspension, drivetrain, brakes, and bodywork. The manual offers step-by-step repair and rebuild instructions, preventive maintenance schedules, troubleshooting guides, electrical diagnostics with wiring diagrams, and essential technical specifications such as torque values and special tool requirements. Its extensive coverage is designed to assist owners and technicians in keeping the DT125R in optimal working condition. 🏷️ Basic Information Identification Make: Yamaha Model: DT125R Year: 1987-1988 Vehicle Type: Dual-Sport Motorcycle Generation Generation Code: 34X / 4ES 👋 Introduction Market Position Market Segment: Entry-level to mid-range dual-sport motorcycles, popular for off-road riding and light trail use. Competitive Analysis Key Competitors: Honda CR125R, Kawasaki KDX125, Suzuki RM125, KTM 125 EXC of similar eras. Key Features Vehicle Appeal: Known for its lightweight, agile handling, reliable two-stroke engine, and versatility for both on- and off-road use. Manual Value Cost Effectiveness: Inexpensive way to maintain and repair the vehicle compared to professional shop rates. User Base: Targeted at both DIY enthusiasts and professional mechanics seeking detailed repair information. 📋 Manual Details Coverage Areas Manual Title: Yamaha DT125 DT125R 1987-1988 Workshop Service Repair Manual PDF Download Covered Models: Yamaha DT125R Covered Years: 1987, 1988 Page Count Estimated Page Count: 300+ Manual Type Manual Type: Workshop Service Repair Manual / Factory Service Manual Language Language: English Format Digital Format: PDF 📖 Manual Coverage Systems Covered Engine Mechanical: Full coverage including disassembly, inspection, repair, and reassembly of engine components. Engine Electrical: Comprehensive details on ignition system, charging system, lighting, and starter motor. Emission Control: Specific information related to emission control systems for the applicable model years. Fuel System: Detailed coverage of carburetor system, fuel tank, fuel lines, and fuel pump operation. Suspension System: Front fork and rear monoshock suspension servicing, adjustments, and overhaul procedures. Clutch System: Maintenance, adjustment, and repair of the clutch assembly and actuation mechanism. Transmission: Coverage of the 6-speed manual transaxle, including gear inspection, shift mechanism, and lubrication. Drivetrain: Information on the final drive chain and sprockets, including maintenance and replacement. Steering System: Handlebar, steering stem bearing, and fork alignment servicing. Brake System: Front and rear brake system maintenance, including hydraulic fluid, pad replacement, and caliper servicing. Body Interior Exterior: Fairings, fenders, seat, fuel tank, and other body panel removal, installation, and repair. Body Electrical: Wiring harnesses, switches, controls, lighting, and instrument cluster diagnostics. Restraint System: While primarily a motorcycle, this might refer to user safety recommendations or specific components if applicable. Procedures Included Preventive Maintenance: Detailed schedules and procedures for regular servicing, lubrication, and inspections. Troubleshooting: Systematic diagnostic guides for identifying and resolving common operational issues. Repair And Rebuild: Step-by-step instructions for component removal, overhaul, repair, and reinstallation. Electrical Diagnostics: Includes wiring diagrams and procedures for diagnosing electrical faults. Torque Specifications: Precise torque values for all critical fasteners and bolts. Special Tools: Identification of any specific tools required for certain maintenance or repair tasks. Technical Depth Depth Of Coverage: Comprehensive, suitable for both novice DIY enthusiasts and experienced mechanics. Diagnostic Capability: Extensive troubleshooting sections for diagnosing a wide range of mechanical and electrical issues. 📊 Manual Specifications File Format File Format: PDF Print Quality Printability: Fully printable, allowing users to print specific pages or the entire manual. Zoom Capability: Yes, allows for zooming in and out of illustrations and diagrams. Binding Type Delivery Method: Instant Download Paper Type Software Requirements: Adobe PDF Reader Compression Requirement: WinZip or similar archive utility Compatibility Operating Systems: Compatible with all versions of Windows and Mac OS ⚙️ Engine Specifications Primary Engine Engine Type: 2-stroke, reed valve, liquid-cooled Displacement: 124cc Bore X Stroke: 56.4 mm x 50.0 mm Compression Ratio: 7.2:1 (typical) Performance Horsepower: Approx. 20-22 HP @ 8000 RPM (variant dependent) Torque: Approx. 16-18 Nm @ 7000 RPM (variant dependent) Fuel System Carburetor Model: Mikuni VM28SS (typical) Fuel Type: Unleaded gasoline with appropriate 2-stroke oil pre-mix or oil injection system. Lubrication Lubrication Type: Yamaha's Autolube system (oil injection) or manual pre-mix. 🔧 Transmission Standard Transmission Type: Constant mesh 6-speed sequential manual Clutch Type: Wet, multiple disc Features Gear Ratios: Specific gear ratios available within the manual. Final Drive: Chain drive 📐...