Stators

Is your battery not charging while riding, or are the lights getting dim on your motorcycle or ATV? Then the stator may be the cause. It is the stationary coil in the alternator that generates the power. We stock new 12V stators and stator coils to replace worn or burnt-out original parts.

What the stator does in the charging system

The stator is typically located behind a cover on the engine and generates alternating current when the magnets in the flywheel rotate around the coils. The current is rectified and limited by a voltage regulator before it charges the battery. A faulty stator can show up as a battery that drains while riding, dim lights or an engine that cuts out. If you replace the stator, it is a good idea to check the regulator and connectors at the same time, because a fault in one place can put strain on the other parts.

How to choose the right stator

• Model and year: The product names specify particular vehicles, e.g. Yamaha YFM400 Grizzly IRS 07-08 or Polaris Sportsman.
• OEM part number: Some stators state which original part they replace. One example is the stator from TwinPower for 99-01 FLH FLT, which replaces H-D 29987-99.
• Output and voltage: Compare with the original. For example, 12V or 40 Amp may be stated in the product name.
• Connectors and design: Check that the connectors, wires and mounting holes match the part you are removing.

In this category you will find stators from brands such as Arrowhead and QuadBoss.

Installation and troubleshooting

Measure the stator's resistance and AC voltage and compare with the values in the service manual before you order. Depending on the model, it may be necessary to remove the flywheel and replace the cover gasket. The battery must be fully charged, e.g. with a battery charger, otherwise the measurements can give a misleading picture.

Frequently asked questions

How do I find out whether the stator is faulty?

Measure the resistance between the stator's phases and to ground, and measure the AC voltage at different engine speeds. Compare with the values in the service manual. Also check the battery, regulator and connectors, as they can cause similar symptoms.

Should the regulator be replaced at the same time as the stator?

It is not always necessary. However, test the regulator and connectors before putting the new stator into service. A faulty regulator or a corroded or burnt connector can strain a new stator and shorten its lifespan.

Can I fit a new stator myself?

That depends on the model and your tools. On some models the stator sits directly behind the cover. On others the flywheel has to be removed with a puller. Follow the service manual for tightening torques, and use a new gasket if the cover requires it.