Yamaha YJ125S Service Manual

About this manual

This service manual is intended for Yamaha dealers and qualified mechanics working on the YJ125S scooter. It contains step‑by‑step instructions, exploded diagrams, and safety warnings for disassembly, inspection, and repair of the vehicle.

The manual is organized into chapters covering general information, specifications, periodic checks, chassis, engine, carburetor, electrical system, and troubleshooting, with symbols indicating special tools, lubricants, and torque values.

What's inside

• General Information
• Specifications
• Periodic Checks and Adjustments
• Chassis
• Engine
• Carburetor
• Electrical System
• Troubleshooting

Frequently asked questions

Where is the vehicle identification number (VIN) located on the YJ125S?

The VIN is stamped into the steering head pipe.

Where can the model label be found on the YJ125S?

The model label is affixed to the seat.

What are common causes for a turn signal that remains lit?

A faulty turn signal relay or a burnt‑out turn signal bulb can cause the turn signal to stay lit.