Target Audience:
Yamaha DT125R owners, mechanics, restorers, and enthusiasts seeking detailed repair and maintenance information.
Value Proposition:
Provides the same in-depth information used by professional technicians, enabling owners to perform complex repairs and maintenance themselves, saving significant costs.
Illustration Quality:
Detailed illustrations, drawings, and photos to guide procedures, including enlarged inset views for critical components.
Navigability:
Numbered table of contents for quick information retrieval and bold figure numbers to match illustrations with instructions.
Safety Notes:
Includes notes, cautions, and warnings throughout to highlight critical safety and procedural information.
General Coverage:
Full Service Repair
Specific Systems:
Engine, Transmission, Fuel System, Ignition System, Electrical System, Chassis, Suspension, Brakes, Cooling System, Lubrication System, Bodywork, Troubleshooting, Wiring Diagrams.
Estimated Page Count:
While not explicitly stated, comprehensive full service repair manuals for this era typically range from 300 to 600+ pages depending on the detail.
Manual Type:
Service and Repair Manual
Delivery Method:
Instant Download
Compatibility:
All Windows and Mac versions
Engine Overhaul:
Yes, includes detailed breakdown, assembly, and tuning procedures for the 125cc two-stroke engine.
Transmission Service:
Yes, covering gearbox, clutch, and shifting mechanism maintenance and repair.
Electrical Diagnostics:
Yes, with comprehensive wiring diagrams for ignition, lighting, and other electrical components.
Suspension And Steering:
Yes, including fork and rear shock absorber servicing, along with steering head bearing maintenance.
Braking System:
Yes, covering hydraulic front disc and rear drum brake system maintenance and component replacement.
Routine Maintenance:
Yes, including oil changes, chain adjustment, filter cleaning/replacement, spark plug service.
Troubleshooting Guide:
Yes, detailed diagnostic procedures for common and uncommon issues.
Rebuilding And Reconditioning:
Yes, designed for full restoration and component rebuilding.
Torque Specifications:
Yes, essential for proper assembly and component longevity.
Diagnostic Capabilities:
Advanced, covering electrical circuit tracing and component testing.
Repair Scope:
Comprehensive, suitable for professional technicians and experienced DIY enthusiasts.
PDF Quality:
High Resolution, fully printable.
Printability:
All pages are printable, allowing for on-the-bench use.
Binding Type:
N/A (Digital Download)
Paper Type:
N/A (Digital Download)
Software Requirements:
Adobe PDF Reader, WinRAR (for potential archive extraction).
Engine Type:
Two-stroke, liquid-cooled, single-cylinder
Displacement:
123 cc (7.5 cubic inches)
Bore X Stroke:
Typically 56.4 mm x 50.0 mm for this model, but manual confirmation is advised.
Compression Ratio:
Likely around 7.2:1 or similar for this era of two-stroke, manual confirmation needed.
Horsepower Output:
Approx. 21-23 hp at 8000 rpm (subject to regional tuning and specific model variant, manual confirmation required).
Torque Output:
Approx. 19-20 Nm at 7000 rpm (subject to regional tuning and specific model variant, manual confirmation required).
Carburetor Type:
Mikuni VM28SS or similar, with specific jetting and adjustment procedures detailed in the manual.
Fuel Type:
Unleaded gasoline with a recommended octane rating (e.g., 95 RON) and a proper two-stroke oil mix (typically 50:1 or as specified).
Overall Length:
Varies slightly by model year but typically around 2050-2100 mm.
Overall Width:
Varies, but typically around 800-830 mm.
Overall Height:
Varies, but typically around 1160-1180 mm.
Dry Weight:
Approximately 115-120 kg.
Gross Vehicle Weight Rating:
Manual will specify, but typically around 250-270 kg.
Oil Change Interval:
Refer to manual for specific mileage/time recommendations for engine oil and 2-stroke oil injection system. Typically every 2000-3000 km.
Spark Plug Service:
Refer to manual for recommended service interval and plug type (e.g., NGK BR9ES or equivalent).
Air Filter Cleaning:
Regular inspection and cleaning, especially if used in dusty conditions. Interval will be specified in manual.
Engine Oil:
Manual will specify viscosity grade (e.g., SAE 10W-30 or 10W-40) and API classification for the gearbox oil. Typically a dedicated gearbox oil is used.
Two Stroke Oil:
High-quality JASO FD or API TC certified two-stroke engine oil for the oil injection system.
Coolant Type:
Ethylene glycol-based coolant, mixed 50/50 with distilled water for the liquid-cooled engine.
Carburetor Clogging:
Common on older two-strokes due to fuel degradation; requires periodic cleaning and carburetor kit replacement.
Exhaust Port Fouling:
Can occur with improper oil mix or excessive idling; requires decarbonization of the exhaust port and power valve.
Clutch Wear:
Friction plates can wear over time, affecting clutch engagement; manual will detail replacement procedures and specifications.
Suspension Seals:
Fork and shock seals can degrade, leading to leaks; manual covers seal replacement and fluid changes.
Yamaha Motorcycles:
Yamaha has a long and storied history in motorcycle manufacturing, known for innovation and performance, particularly in off-road and dual-sport segments.
Dt Series Legacy:
The DT series has been a cornerstone of Yamaha's dual-sport offerings, evolving from the iconic early DT models to more performance-oriented versions like the DT125R.
Dt125R Significance:
The DT125R represented a more aggressive, performance-focused iteration of the popular 125cc dual-sport, often featuring more advanced suspension and engine tuning for off-road capability.
Production Period For Model:
The DT125R model was produced over several years, with the 1987-1988 period representing a specific generation.
