Model Code:
Likely specific to regional variants, e.g., 3SW, 4BL, 4X7 (typical Yamaha codes)
Production Years Covered:
2002, 2003, 2004, 2005, 2006, 2007, 2008
Target Audience:
Owners, independent repair shops, and mechanics working on the Yamaha DT125RE.
Segment:
Lightweight Dual-Sport Motorcycle
Key Competitors:
Honda CRM125R, Suzuki RM125 (off-road variant, but similar displacement), Kawasaki KDX125SR.
Design Philosophy:
Compact, agile, and reliable dual-sport machine suitable for on-road commuting and light off-road excursions.
Durability:
Yamaha's reputation for robust 2-stroke engines and well-built chassis.
Engine System:
Detailed diagnostics, disassembly, assembly, tuning, and troubleshooting for the 125cc 2-stroke engine.
Fuel System:
Carburetor (likely Mikuni VM series), fuel lines, fuel tank, and related components.
Ignition System:
CDI ignition, spark plug, coil, and timing checks.
Cooling System:
Liquid cooling system, radiator, hoses, coolant specifications, and thermostat operation.
Transmission System:
6-speed gearbox, clutch operation, inspection, adjustment, and overhaul.
Drivetrain:
Chain drive, sprockets, lubrication, and inspection.
Suspension Front:
Telescopic front forks, seals, oil levels, inspection, and adjustment.
Suspension Rear:
Monoshock rear suspension, linkage, bearing checks, and shock absorber.
Braking System:
Hydraulic disc brakes (front and rear), brake pads, fluid types, bleeding procedures, and caliper maintenance.
Wheel And Tires:
Spoked wheels, rim inspection, spoke tension, tire pressure, and replacement procedures.
Electrical System:
Wiring diagrams, battery maintenance, lighting, horn, and starter motor.
Frame And Bodywork:
Frame inspection, body panel removal/installation, seat, fuel tank, and fairings.
Scheduled Maintenance:
Includes routine checks and replacements at specified intervals (e.g., oil changes, filter replacements, chain adjustments).
Troubleshooting Guides:
Diagnostic charts and symptom-based troubleshooting for common issues.
Engine Overhaul:
Complete procedures for engine disassembly, component inspection, and reassembly.
Suspension Rebuild:
Fork seal replacement, shock absorber servicing, and linkage bearing replacement.
Carburetor Tuning:
Jetting specifications, idle speed adjustment, and mixture control.
Brake System Repair:
Pad replacement, caliper servicing, and hydraulic system bleeding.
Electrical Diagnostics:
Using wiring diagrams to diagnose faults in the electrical system.
Torque Specifications:
Precise torque values for all critical fasteners.
Diagnostic Capability:
Advanced diagnostic procedures, fault code interpretation (if applicable to this era/model), and troubleshooting flowcharts.
Rebuild Scope:
Covers complete disassembly and reassembly of major components, including the engine and transmission.
Special Tools:
Lists any specialized tools or equipment required for specific repair procedures.
Engine Type:
2-stroke, liquid-cooled, reed valve induction
Bore X Stroke:
56.5 mm x 50.6 mm
Compression Ratio:
Approximately 7.2:1 (typical for this engine type)
Power Output:
Estimated 20-25 HP at 8,000 RPM (regionally dependent)
Torque Output:
Estimated 18-20 Nm at 7,000 RPM (regionally dependent)
Carburetor Model:
Likely a Mikuni VM28 or similar
Fuel Type:
Unleaded gasoline (RON 91 or higher recommended)
Oil Mixing:
2-stroke pre-mix or Autolube system (check manual for specifics)
Fuel Tank Capacity:
Approximately 10-12 Liters
Safety Certification:
CE, EPA, or other regional emissions and safety standards depending on market.
Brakes:
Front and rear hydraulic disc brakes for reliable stopping power.
Lighting:
Headlight, taillight, brake lights, and turn signals for visibility.
Frame Construction:
Durable steel frame designed for off-road stress and road stability.
Ergonomics:
Upright riding position for comfort and control.
Oil Change Interval:
Refer to manual, typically every 3,000-5,000 km for transmission oil.
Air Filter Cleaning:
Inspect/clean every 1,000-2,000 km, replace as needed.
Spark Plug Replacement:
Typically every 3,000-6,000 km, depending on usage and plug type (e.g., NGK BR9ES).
Chain Lubrication:
Lubricate every 500 km or after riding in wet conditions.
Fork Oil Change:
Recommended every 10,000-15,000 km or as per manual.
Engine Oil:
Yamalube 2R or equivalent API TC-W3 certified 2-stroke oil (for Autolube).
Transmission Oil:
Yamalube SAE 10W-40 API GL-4 or GL-5 Gear Oil (specific viscosity and spec in manual).
Coolant:
Yamaha Super Coolant or equivalent ethylene glycol-based antifreeze with corrosion inhibitors (50% mix).
Brake Fluid:
DOT 4 hydraulic brake fluid (DOT 3 acceptable but DOT 4 preferred).
Power Valve:
The YPVS (Yamaha Power Valve System) can accumulate carbon and require cleaning or adjustment to maintain optimal performance.
Carburetor Clogging:
Like many 2-strokes, the carburetor can be susceptible to clogging from old fuel or debris, requiring regular cleaning.
Exhaust Carbon Buildup:
Carbon deposits can form in the exhaust port and silencer, affecting performance and requiring periodic cleaning.
Clutch Wear:
Frequent aggressive use can lead to clutch plate wear, requiring adjustment or replacement.
