This manual covers the DT125R, produced for the 1987 and 1988 model years. The DT125R is a testament to heritage in crafting reliable and capable dual-sport motorcycles, building on a lineage that dates back decades. Known for its robust two-stroke engine, the DT125R offers a blend of off-road prowess and on-road usability, making it a popular choice for riders seeking adventure and versatility. Its engineering quality and performance characteristics defined a generation of dual-sport machines, solidifying reputation in this segment. This comprehensive factory service repair manual provides in-depth technical knowledge essential for owners and independent repair shops. It details routine maintenance, troubleshooting, and repair procedures for all major systems, including the engine, fuel system, cooling system, drivetrain, chassis, and electrical components. With hundreds of pages of detailed illustrations, diagrams, and specifications, this English-language manual empowers users to perform everything from basic upkeep to complete engine rebuilds, ensuring the longevity and optimal performance of their DT125R. 🏷️ Basic Information Identification Make: Yamaha Model: DT125 Model Variant: DT125R Year: 1987-1988 Codes Vin Decoder Reference: Refer to manual for VIN specifics 👋 Introduction Market Position Target Audience: Yamaha DT125R owners and independent repair shops seeking comprehensive, factory-authorized service information. Competitive Analysis Value Proposition: Provides the same in-depth technical knowledge as professionals, enabling informed maintenance, repair, and cost savings. Key Features Format Advantage: Digital PDF format allows for easy searching, printing of specific pages, and avoidance of physical manual wear and tear. Content Quality: Includes hundreds of pages with detailed illustrations, diagrams, photos, and specifications. 📋 Manual Details Coverage Areas Covered Models: Yamaha DT125R (all styles covered) Covered Years: 1987, 1988 Page Count Estimated Pages: Hundreds Manual Type Type: Factory Service Repair Manual Language Language: English Format Format: PDF Download 📖 Manual Coverage Systems Covered Engine: General Information, Engine Top End, Engine Lubrication System, Crankshaft/Transmission Fuel System: Fuel System Cooling System: Cooling System Drivetrain: Clutch, Engine Removal/Installation, Crankshaft/Transmission, Final Drive Chassis: Wheels/Tires, Brakes, Suspension, Steering, Frame Electrical: Electrical System, Wiring Diagrams Miscellaneous: Appendix Procedures Included Maintenance: Routine maintenance, fluid checks, component lubrication Troubleshooting: Engine fault symptom diagnosis, advanced troubleshooting guide Repair: Step-by-step repair procedures for all covered systems, component replacement Diagnostics: Engine management system analysis, electrical system diagnostics, part testing techniques Rebuild: Complete engine rebuild, transmission overhaul Technical Advice: Mechanic tips, advice for owners on interacting with service professionals Technical Depth Depth: Comprehensive factory-level detail for professional technicians and advanced DIY mechanics. 📊 Manual Specifications File Format Format: PDF Compatibility: Windows, macOS, Linux (requires Adobe PDF Reader) Print Quality Printability: Printable without restriction (individual pages or entire manual) Resolution: High quality, suitable for clear printing of diagrams and text. Binding Type Binding: Digital Download (user printable, can be bound or stored electronically) Paper Type Paper Type Recommendation: Standard copy paper for printing, heavier stock recommended for frequently referenced sections. ⚙️ Engine Specifications Primary Engine Type: 2-stroke, single-cylinder, reed valve induction Displacement: 124 cc (approximately) Bore X Stroke: Refer to manual for precise specifications Cooling: Liquid-cooled (typically with a radiator) Performance Horsepower: Refer to manual for specific model year output (typically around 15-20 HP) Torque: Refer to manual for specific model year output Fuel System Carburetor Type: Mikuni VM series (specific model number in manual) Fuel Type: Unleaded gasoline (refer to manual for octane rating) Fuel Mixture: 2-stroke oil/gasoline mix (specific ratio and oil type in manual) 🔧 Transmission Standard Type: 6-speed constant mesh, return shift Features Clutch: Wet, multi-plate Gear Ratios: Detailed in manual Transmission Oil: Yamalube (specific grade and capacity in manual) 📐 Dimensions Exterior Overall Length: Refer to manual Overall Width: Refer to manual Overall Height: Refer to manual Weights Dry Weight: Refer to manual (typically around 110-120 kg) Wet Weight: Refer to manual 🛡️ Safety Features Ratings Safety Certification: Refer to regional homologation documents Active Features Braking System: Front: Disc brake; Rear: Drum brake (or Disc on some R models - verify with manual) Suspension Front: Telescopic fork Suspension Rear: Monocross suspension 💡 Technology Features Infotainment Features: Basic analog instrument cluster (speedometer, tachometer, odometer, indicators). Driver Assistance Features: None Connectivity Features: None 🔧 Maintenance Service Intervals Oil Change Transmission: Refer to manual for specific mileage/time intervals (e.g., every 3000-5000 km) Spark Plug Check Replace: Refer to manual (typically every 1000-2000 km) Air Filter Cleaning: Refer to manual (frequency dependent on operating conditions) Fluid Specifications Engine Oil Mix: Yamalube 2-stroke oil or equivalent (100% synthetic recommended) at specified ratio (e.g., 20:1 or 30:1) Transmission Oil: Yamalube Gear Oil (GL-4 80W or 90W) or equivalent Coolant: Ethylene glycol-based antifreeze/coolant (50% mixture with distilled water) Known Issues Common Wear Items: Piston rings, clutch plates, exhaust packing, bearings (e.g., swingarm, wheel, steering stem) Carburetion Issues: Clogged jets, worn needle/seat due to fuel quality or age Power Valve Operation: Carbon buildup affecting operation, requiring cleaning Technical Specifications Ignition Timing: Refer to manual (critical for 2-stroke performance)...