Segment:
Lightweight off-road/enduro motorcycle segment, popular for trail riding and light competition.
Competitors:
Honda CR series, Kawasaki KDX series, Suzuki RM series (specific to their displacement classes).
Attributes:
Durable two-stroke engine, capable off-road suspension, lightweight chassis, reliability.
Manual Value Proposition:
Provides essential, detailed, and comprehensive information for owners and mechanics to maintain and repair the Yamaha DT 125 R, ensuring longevity and optimal performance.
Engine:
Complete engine overhaul, including disassembly, assembly, inspection, and adjustment of all internal components (piston, rings, cylinder, crankshaft, connecting rod, bearings, etc.)
Fuel System:
Carburetor (Mikuni VM series) tuning, cleaning, inspection, jetting specifications, fuel tank, fuel lines, fuel petcock.
Ignition System:
CDI ignition system, spark plug selection and gap, ignition timing, stator, coil, and wiring diagrams.
Transmission:
Gearbox internal inspection, gear selection, clutch assembly, clutch cable adjustment, clutch plates, transmission oil specifications and change intervals.
Cooling System:
Air-cooled engine operation, heat dissipation, and maintenance.
Exhaust System:
Exhaust pipe and silencer inspection, maintenance, and typical wear points.
Frame And Suspension:
Front fork (telescopic) disassembly, service, oil levels, seals, and adjustments. Rear shock absorber inspection and maintenance. Frame inspection for cracks or damage.
Brakes:
Front and rear brake systems (likely drum or disc depending on specific market variants), brake pad/shoe inspection and replacement, brake fluid specifications (if applicable), bleeding procedures, brake lever and pedal adjustments.
Wheels And Tires:
Spoke tensioning, wheel bearing inspection, tire pressure specifications, tire replacement, wheel rim maintenance.
Electrical System:
Lighting system (headlight, taillight, indicators), battery maintenance and testing, charging system (alternator, rectifier/regulator), fuses, wiring diagrams, horn, starter motor (if electric start equipped).
Bodywork:
Fairings, fenders, seat removal and installation, fuel tank removal and installation, graphics and decals.
Controls:
Handlebar, throttle, clutch lever, brake lever, gear shift lever, footpegs, and their associated cables and adjustments.
Maintenance:
Routine maintenance tasks, oil changes, filter replacements, lubrication points, chain adjustment, spark plug checks, air filter cleaning.
Troubleshooting:
Systematic diagnostic procedures for common problems, identifying causes and solutions for performance issues, starting difficulties, electrical faults, etc.
Repair:
Detailed step-by-step instructions for repairing or replacing virtually all components of the motorcycle.
Disassembly Assembly:
Comprehensive instructions for taking apart and putting back together various sub-assemblies and components.
Adjustments:
Specific procedures for adjusting clutch, throttle, brakes, suspension, and engine parameters.
Technical Data:
Specifications, torque values, measurements, wear limits, and fluid capacities critical for accurate servicing.
Wiring Diagrams:
Detailed electrical schematics to aid in diagnosing and repairing electrical issues.
Depth:
Comprehensive, from basic maintenance to complete engine and chassis rebuilds.
Visuals:
Pictorial diagrams, exploded views, and detailed illustrations guiding through procedures.
Special Tools:
Identification and usage instructions for specialized tools required for specific repair tasks.
Type:
2-stroke, single-cylinder, reed valve induction
Displacement:
123 cc (approximate)
Bore X Stroke:
56.0 mm x 50.0 mm (typical for DT125 variants)
Compression Ratio:
Typically around 7.2:1 (subject to variations)
Horsepower:
Approximately 18-20 HP (subject to market regulations and specific year)
Torque:
Approximately 15-17 Nm (subject to variations)
Carburetor Model:
Mikuni VM26SS or similar
Fuel Type:
Unleaded gasoline with appropriate 2-stroke oil pre-mix (typically 50:1 or as specified)
Transmission Oil Type:
Yamalube 2-stroke oil (or equivalent API-TC, JASO FD rated)
Transmission Oil Capacity:
Refer to manual for specific capacity (typically around 0.8 - 1.0 liters)
Oil Change Interval:
Refer to manual, typically every 1000-3000 km or annually.
Spark Plug Service:
Inspect every 1000-2000 km, replace as needed based on condition.
Air Filter Service:
Clean every 1000-2000 km, replace as needed.
Chain Maintenance:
Lubricate and adjust chain every 500-1000 km.
Fork Oil Type:
Yamaha Fork Oil (or equivalent SAE 10W or 15W)
Fork Oil Quantity:
Refer to manual for exact volume per leg (typically around 300-350 ml)
Common Wear Items:
Clutch plates, piston and rings (due to two-stroke nature), exhaust packing, suspension seals, wheel bearings.
Carburetor Issues:
Can become clogged with debris or age, leading to poor performance; jetting may need adjustment for altitude or modifications.
Electrical Issues:
Less common, but wiring connections can corrode over time, especially in wet conditions.
Frame Wear:
Frame can experience stress cracks or wear at mounting points with heavy off-road use.
