Positioning:
A robust dual-sport motorcycle known for its off-road capability and reliable two-stroke engine, popular in its era for light trail riding and commuting.
Competitors:
Competed with other dual-sport motorcycles in the 125cc class from brands like Honda (CRM125), Kawasaki (KDX125), and Suzuki (TS125).
Features:
Lightweight chassis, capable suspension, reliable two-stroke power, versatile for on-road and off-road use.
Engine:
Complete engine disassembly, assembly, tuning, troubleshooting, and diagnostics.
Fuel System:
Carburetor inspection, adjustment, cleaning, and repair; fuel tank and lines maintenance.
Cooling System:
Radiator, hoses, thermostat, and coolant checks and replacement.
Ignition System:
Spark plug specifications, ignition coil testing, CDI unit diagnostics.
Transmission Drivetrain:
Clutch operation, gearbox inspection, lubrication, and troubleshooting.
Chassis Suspension:
Front fork disassembly, servicing, and adjustment; rear shock absorber inspection and replacement.
Braking System:
Front and rear brake pad replacement, caliper servicing, hydraulic system bleeding, and inspection.
Electrical System:
Wiring diagrams, lighting system, battery maintenance, charging system testing, and starter motor troubleshooting.
Wheels Tires:
Tire pressure recommendations, wheel bearing maintenance, spoke tension adjustment.
Frame Bodywork:
Frame inspection, fairing removal and installation, seat maintenance.
Maintenance:
Routine servicing, oil changes, filter replacements, lubrication points, chain adjustment.
Troubleshooting:
Step-by-step diagnostic procedures for common and uncommon issues.
Repair:
Detailed instructions for component repair and replacement, including full engine rebuilds.
Rebuilds:
Complete engine, gearbox, and suspension component rebuild procedures.
Adjustments:
Carburetor, clutch, brake, and suspension adjustments.
Wiring Diagrams:
Clear and detailed electrical schematics.
Depth:
Designed for professional technicians, covering detailed diagnostic procedures and complete overhaul instructions.
Type:
2-stroke, liquid-cooled, reed valve
Bore X Stroke:
56.4 mm x 49.1 mm
Compression Ratio:
7.4:1 (approx.)
Horsepower:
Approx. 17-20 HP (depending on market regulations)
Torque:
Approx. 10-12 lb-ft (depending on market regulations)
Carburetor:
Mikuni VM28 or similar
Fuel Type:
Unleaded gasoline (min. 91 octane recommended)
Oil Mixture:
Pre-mix or Autolube (Yamalube 2-stroke oil recommended)
Safety Standards:
Designed to meet relevant motorcycle safety standards of the time.
Brakes:
Disc brakes front and rear for effective stopping power.
Lighting:
Headlight, taillight, and turn signals for visibility.
Frame Construction:
Durable steel frame provides a stable riding platform.
Features:
Basic analog instrumentation including speedometer, odometer, and indicator lights.
Features:
N/A (This model predates significant driver-assistance technologies on motorcycles).
Features:
N/A (No onboard connectivity features).
Oil Change:
Every 3,000 km (1,800 miles) or annually.
Air Filter Cleaning:
Every 1,000 km (600 miles), or more frequently in dusty conditions.
Spark Plug Check:
Every 3,000 km (1,800 miles).
Chain Lubrication Adjustment:
Every 500 km (300 miles) or after washing/riding in rain.
Engine Oil:
Yamalube 2-stroke oil or equivalent (API TC, JASO FD)
Transmission Oil:
Yamaha Gear Oil (e.g., 10W-30 API SE or higher)
Coolant:
Yamaha Coolant or equivalent (ethylene glycol based, 50/50 mix with distilled water)
Common Problems:
Carburetor gumming if not used regularly, exhaust port blockage on 2-stroke engines, potential wear on reed valves, rear shock absorber wear.
Preventative Maintenance:
Regular cleaning of the carburetor, proper fuel storage, timely engine lubrication, and checking for exhaust leaks.
Heritage:
Yamaha's long history in motorcycle manufacturing, particularly with off-road and dual-sport models, dating back to the iconic DT series.
Evolution:
The DT125RE is part of the evolved DT lineage, incorporating technological advancements and design updates over its predecessors.
Production Period:
The DT125RE was produced for several years, with this manual specifically covering the 2004-2007 model years.
Manufacturing Location:
Primarily manufactured in Japan.
