How to Test an ATV Stator and Fix It If It’s Bad

Your ATV’s stator is an important part of the electrical system, along with the battery and regulator. If you have some kind of electrical problem, particularly a failure to charge, the issue is likely with one of these components. 

An ATV’s stator recharges the battery while the machine is in use, like an alternator in a car. Your ATV may have a single-phase stator, a three-phase stator, or a bar coiled stator, all of which look differently. Most modern ATVs use a three-phase-stator as these components produce more electricity.

Testing the stator gives you an idea of where to start. If the problem is with the stator, someone can fix it. Here’s how to test your ATV’s stator and fix it if it turns out to be a problem. 

Understanding the Stator

Your ATV’s service manual will contain the information you need about your type of stator. It should also illustrate any extra components on your particular model. No matter the type of stator, testing it is a similar process.

Before testing the stator, however, you may wish to take a few additional steps. First, check the battery by placing it on a different charger. Take the time to look for corrosion, and clean the connectors and wiring. If none of those actions fix the battery charging issue, it is time to test the stator.

Testing the ATV Stator

To test the ATV stator, you will again need the multimeter. You will first perform a static test, or a test done without the engine running and without the stator attached to the ATV. Make sure the ATV is off when you disconnect the stator.

With your multimeter set to ohms, get to work resistance testing each circuit. Connect the multimeter leads to the terminals in the stator’s electrical connector, testing between pins 1 and 2, 2 and 3, and 1 and 3. Compare the multimeter reading to what it should be in your service manual.

The next test is to determine if the stator is shorting out to the ground. For this you will put one meter lead in the connector and the other on the stator body. The correct reading in this situation is OL, or open line. If you see another reading, the stator has a problem. Perform this measurement for each coil/winding/phase. 

Another test is the dynamic test, this time with the motor running. This will only work if your battery has some charge. You must set your multimeter to AC voltage for this measurement. You will likely need a friend to help.

With the engine running, measure between coils/pins by connecting the multimeter lead to the terminals in the electrical connector for the stator. Again, measure between 1 and 2, 2 and 3, and 1 and 3. You are looking for a positive reading.

You can also re-do this test with an increased engine RPM. In this case, you are looking for the reading between terminals to increase as the RPM increases. A voltage reading that remains the same from the static test to the dynamic test indicates a problem. 

Fixing an ATV Stator

Fixing a stator usually involves unwinding and cleaning the original stator core, then rewinding it with a machine or carefully by hand. It starts with looking at the coil heads for damaged or burned wires, then cutting out the protective rubber coating from damaged coils. Note which direction the wire wraps around the coil head, then remove terminal clips from the base with a screwdriver. 

The next step is to unwind the damaged wire. After this, you will clean the surface of the stator head with fine-grade steel wool. Wipe it clean afterward. The new wire should be the same gauge as the old, wrapped around the heads in the same direction as before. There should be no gaps between the wire wrappings, and terminal leads will require an additional length at the top and bottom.

Crimp the terminal leads to those one-inch lengths using pliers, and attach the leads to the stator with a screwdriver. Then, test the functionality of the repaired stator with your multimeter in ohm setting mode. If all looks good, coat the new wiring with liquid rubber and allow it to set.

If repairing a stator is outside of your skillset or you would rather get a new stator, a full replacement is possible. You can either perform the installation yourself or outsource the whole process to a reliable ATV repair expert.