125cc Stator Wiring Diagram: A Comprehensive Guide

The stator is an essential component of a motorcycle’s electrical system, which generates and distributes electrical power to various parts of the bike. Wiring a stator can be a challenging task for novice mechanics, but with the right guidance, it can become a simple process. This article will provide you with a comprehensive guide to wiring a 125cc stator, which will help you understand the wiring process and identify common issues.

What is a Stator in a Motorcycle?

The stator is a stationary part of the motorcycle’s electrical system, which generates electrical power that is transferred to the battery and other electrical components. It consists of a series of windings or coils that generate AC current when the bike’s engine is running. The stator is responsible for producing electrical power to run the headlights, taillights, turn signals, horn, and other electrical components of the bike.

The stator is fixed on the motorcycle’s engine casing and is located near the flywheel. It is often referred to as the alternator and works in conjunction with the rectifier/regulator to convert the AC current into DC current, which is required to charge the battery.

Stator Winding Diagram

Here is a diagram that shows the stator winding in a 125cc motorcycle:

Coils Color Code
Coil 1 Green
Coil 2 White
Coil 3 Yellow
Coil 4 Red

How to Wire a 125cc Stator

Wiring a 125cc stator is not a difficult task, but it requires attention to detail and some basic knowledge of electrical systems. Here’s a step-by-step guide to wiring a 125cc stator:

Step 1: Disconnect the Battery

Before working on the motorcycle’s electrical system, it’s essential to disconnect the battery to avoid any electrical shock and short circuits. You can disconnect the battery by removing the negative cable from the battery terminal.

Step 2: Remove the Stator Cover

To access the stator, you need to remove the stator cover, which is located on the left side of the engine casing. Use a wrench or socket to remove the bolts and nuts that hold the stator cover in place.

Step 3: Identify the Coils

Once you have removed the stator cover, you can identify the coils that need to be wired. The 125cc stator has four coils, which are identified by their color-code. The green coil is Coil 1, the white coil is Coil 2, the yellow coil is Coil 3, and the red coil is Coil 4.

Step 4: Connect the Coils

To wire the stator, you need to connect the coils according to the diagram provided above. Connect Coil 1 to the green wire, Coil 2 to the white wire, Coil 3 to the yellow wire, and Coil 4 to the red wire. Use a soldering iron and heat shrink tubing to connect the coils securely.

Step 5: Reassemble the Stator Cover

Once you have wired the stator, you can reassemble the stator cover by tightening the nuts and bolts. Make sure that the cover is placed correctly and that there are no loose parts.

Step 6: Reconnect the Battery

Once you have assembled the stator cover, you can reconnect the battery by attaching the negative cable to the battery terminal. Make sure that the connections are tight and that there are no loose wires or cables.

Common Issues with Stator Wiring

Stator wiring can be a tricky job, and there can be several issues that you may face during the process. Here are some of the common problems that you can encounter:

Problem 1: Incorrect Wiring

The most common problem with stator wiring is incorrect wiring. If you wire the coils incorrectly, the bike’s electrical system may not function correctly, and there may be issues with the lights, horn, and other electrical components.

Problem 2: Loose Connections

Loose connections can also cause issues with the stator wiring. If the connections are not tight, they may become loose over time, which can lead to shorts and electrical problems. It’s essential to make sure that all the connections are tight and secure before reassembling the stator cover.

Problem 3: Faulty Stator

Sometimes, the stator itself may be faulty, which can cause issues with the electrical system. If you have checked the wiring and connections and are still facing issues, it’s essential to test the stator using a multimeter to identify any faults.

Frequently Asked Questions

Q1: How do I know if my stator is faulty?

A faulty stator can cause issues with the bike’s electrical system, such as dimming lights, weak horn, and dead battery. You can check the stator’s output by using a multimeter to measure the AC voltage output. If the stator is faulty, you may not get any voltage reading or a low reading.

Q2: Can I wire a 125cc stator myself?

Wiring a 125cc stator is not difficult if you have basic knowledge of electrical systems and attention to detail. If you are a novice mechanic, it’s better to get professional help or guidance to avoid any electrical problems.

Q3: How often should I check my stator wiring?

It’s essential to check the stator wiring periodically to ensure that the electrical system is functioning correctly. You can check the wiring when you perform routine maintenance or when you face any electrical issues with the bike.


The stator is an essential component of a motorcycle’s electrical system, and wiring it correctly is crucial for proper functioning. This guide has provided you with an in-depth understanding of the 125cc stator’s wiring process, including the diagram and step-by-step instructions. If you follow these instructions carefully, you can wire the stator yourself and avoid any electrical problems. Remember to check the wiring periodically and seek professional help if you face any difficulties.