Vehicle Type:
Dual-purpose motorcycle, popular for trail riding, off-road use, and light on-road commuting.
Competitors:
Competed with other 125cc dual-sport motorcycles from brands like Honda (e.g., XR125), Kawasaki (e.g., KLR250, although larger displacement), and Suzuki (e.g., DR125).
Defining Characteristics:
Robust 2-stroke engine, lightweight chassis, long-travel suspension, and Yamaha's renowned reliability. This model was known for its torque and off-road prowess for its displacement.
Engine Systems:
Engine assembly/disassembly, lubrication, cooling, fuel system, ignition system, exhaust system, carburetor tuning and overhaul, cylinder head, piston, crankshaft, transmission (gearbox), clutch, and engine diagnostics.
Chassis Systems:
Frame, suspension (front forks, rear shock absorber), steering system, wheels, tires, braking system (front and rear brakes, hydraulic components), electrical system (wiring diagrams, lighting, battery, charging system, ignition components), and bodywork.
Maintenance Procedures:
Scheduled maintenance, lubrication intervals, fluid checks and changes, filter replacements, brake adjustments, chain adjustment, tire pressure checks, spark plug maintenance, air filter cleaning/replacement.
Repair Procedures:
Detailed step-by-step instructions for removal, disassembly, inspection, repair, reassembly, and installation of all major components and systems.
Troubleshooting:
Diagnostic guides for identifying and resolving common and uncommon issues, including electrical faults, engine performance problems, and mechanical failures.
Adjustments:
Carburetor synchronization, ignition timing, clutch play, brake lever travel, throttle cable free play, and suspension settings.
Depth:
Comprehensive, covering everything from basic tune-ups and fluid changes to complete engine rebuilds, electrical system diagnostics, and chassis overhaul. Includes detailed specifications and wear limits.
Format:
PDF (Portable Document Format)
Printability:
Fully printable, allowing users to print specific sections or the entire manual.
Binding:
N/A (Digital Download - PDF)
Paper Type:
N/A (Digital Download - PDF)
Software Requirement:
Adobe Reader (or compatible PDF viewer)
Operating Systems:
Compatible with Windows, Mac, and Linux operating systems.
Engine Type:
2-stroke, reed valve induction, air-cooled single-cylinder
Displacement:
Approximately 123cc (specific displacement may vary slightly by year/market, but the core engine is the 125cc class)
Horsepower:
Typically in the range of 15-20 HP (exact figures vary by year and market tuning). The manual will provide precise specifications.
Torque:
The manual will detail specific torque figures and power curves. Known for good low-to-mid range torque due to its 2-stroke nature.
Carburetion:
Typically equipped with a Mikuni VM series carburetor. Specific model and jetting details will be in the manual.
Fuel Type:
Unleaded gasoline mixed with 2-stroke oil (pre-mix or Autolube system, depending on specific model year variations detailed in the manual).
Type:
6-speed constant mesh manual transmission
Options:
N/A (Manual transmission was standard)
Clutch Type:
Wet, multiple-disc clutch, operated by a cable-actuated lever.
Gear Ratios:
Specific gear ratios for each of the 6 speeds will be provided in the manual.
Overall Length:
Varies by year, but generally around 2150-2200 mm.
Overall Width:
Varies by year, but generally around 800-850 mm.
Overall Height:
Varies by year, but generally around 1150-1200 mm.
Dry Weight:
Typically around 105-115 kg (dry weight).
Wet Weight:
The manual will specify wet weight including all fluids.
Safety Certification:
Specific safety ratings are not typically applied to off-road motorcycles in the same way as cars. The manual will emphasize safe operating procedures.
Braking System:
Front: Disc brake (hydraulic), Rear: Drum brake (mechanical) or Disc brake (hydraulic) depending on specific model year. Manual details inspection and maintenance.
Suspension Damping:
Adjustable front forks and rear shock absorber for optimized handling and stability. Manual covers adjustments and maintenance.
Frame Construction:
Strong steel frame designed for off-road durability and rider control. Manual includes frame inspection and repair guidance.
Oil Change Interval:
The manual will specify the recommended interval for gearbox oil changes, likely every 3,000-5,000 km or annually.
Spark Plug Maintenance:
Recommended checks and replacement intervals for the spark plug will be detailed, crucial for 2-stroke performance.
Air Filter Maintenance:
Regular cleaning or replacement of the air filter is vital for engine health. The manual will specify intervals based on operating conditions.
Engine Oil Type:
For the gearbox: Yamaha recommends specific gear oil grades (e.g., SAE 10W-30 or 10W-40 API GL-4). For 2-stroke oil: Use a high-quality 2-stroke oil specifically designed for air-cooled, performance 2-stroke engines (e.g., Yamalube).
Brake Fluid Type:
DOT 3 or DOT 4 brake fluid, depending on the specific hydraulic system. Manual will specify the exact requirement.
Common Wear Items:
Common wear items may include clutch plates, piston rings, exhaust packing, suspension seals, and brake pads/shoes. The manual addresses their inspection and replacement.
Carburetor Issues:
Carburetors can be prone to clogging from old fuel or dirt, leading to poor running. The manual provides detailed cleaning and tuning procedures.
2 Stroke Engine Maintenance:
Proper 2-stroke oil mixture and regular decarbonization of the exhaust port and piston crown are critical for longevity. The manual emphasizes these aspects.
Yamaha Legacy:
Yamaha has a long and successful history in motorsports and motorcycle manufacturing, known for innovation and performance across various disciplines, including off-road and dual-sport segments.
Dt Series Legacy:
The DT series has a distinguished lineage dating back to the 1960s, known for its go-anywhere capability and ruggedness. The 125cc models were particularly popular as entry-level and versatile machines.
Manufacturing Location:
Likely manufactured in Japan or other Yamaha global production facilities. The manual will focus on the specific models covered.
Model Longevity:
The DT 125 platform was produced for a significant period, indicating its enduring popularity and effective design, with continuous refinements over the years covered by this manual.
Model Recognition:
The Yamaha DT series, in general, has received widespread recognition over its production run for its durability, off-road capability, and value, making it a favorite for both beginners and experienced riders.
Reliability Rating:
Yamaha motorcycles, particularly the DT line, are generally considered highly reliable when properly maintained, a testament to their robust engineering. The manual aids in maintaining this reliability.
