Symptoms of a Bad Motorcycle Stator – All You Need To Know

Symptoms of a Bad Motorcycle Stator – All You Need To Know

Electrical problems on a motorcycle are some of the worst to deal with, especially when it happens to be related to the most critical parts of the bike, like the stator. The stator is responsible for generating electrical power used to run the bike; without it, your motorcycle won’t be going anywhere. 

Most people aren’t comfortable working with the electrical system, either because they don’t understand the intricate wiring or because they would rather not take the risks associated with working around the system. 

In this article, we’ll take a closer look at this important part of your bike. We’ll go over a few signs that tell us if the stator has gone bad and what can be done to get your bike back on the road as quickly as possible. 

What is the Main Symptom of a Bad Motorcycle Stator?

The main function of a stator is to generate electrical energy for the spark plugs. 

Without that power, the battery cannot provide enough power for the spark plugs to function normally, and the bike will not run since it isn’t getting spark. In more minor cases, the bike may have trouble starting in colder temperatures or might misfire, but these are all signs of the same thing: a lack of spark. 

Top 3 Motorcycle Stator Symptoms

motorcycle stator error message

Let’s look at the main indicators of a failed stator in more detail. As mentioned, most symptoms of a bad stator are related to a lack of spark, but the stator isn’t always just broken outright. Some of these symptoms can be seen as early warning signs that the stator is on its way out, and can contribute to catching the problem before it is too critical. 

Quick Drain from the Accessories

This is the first sign you may notice, and the least detrimental to your riding experience. When riding, especially at night, you may notice that your gauges or lights are starting to dim. When you go to start the bike the next day, the battery is drained, so you need to charge it before the bike can be ridden again. 

This happens because the stator is failing to generate enough power to run the accessories, and they are draining the battery in order to function. You may also notice that when you go to turn on the bike, the headlight is not switching on, indicating a total loss of power from the battery. 

Having to charge the battery more frequently will wear it down, so it’s a good idea to have your stator repaired or replaced when this sort of symptom pops up to avoid the cost of replacing the battery as well. 


A somewhat more serious sign of a failing stator is when your bike is misfiring. This is caused by weak or intermittent sparks from the plugs and can eventually lead to greater issues down the road. 

When the stator fails to provide strong power to the spark plugs, they fail to ignite the fuel in the cylinder effectively. This can be a problem that appears sporadically, or it can also be a regular occurrence. In either case, the sputtering effect you may hear from the engine, as well as a delay in power delivery, are clear indications that this is the problem you are dealing with. 

When the bike is misfiring, the stator is still functioning, but not well enough for the bike to run at its best, and it usually isn’t long before the stator fails completely. If your bike is experiencing this symptom, it is a good idea to take it into the shop to have the stator and plugs checked out to avoid further complications. 

Failure to Start

This is the most serious complication of a failed stator. At this stage, the component isn’t generating enough charge to power the spark plugs at all, and the bike will not turn on. This is usually accompanied by a dead battery, but charging the battery if the stator has failed will not allow the bike to start. 

When the stator has completely failed, it must be repaired or replaced. It is also a good idea to have the battery and spark plugs tested at this time as well, just for good measure. 

What Causes a Stator to Fail?

A stator is not generally referred to as a “wear item” or a piece of the motorcycle that is designed to wear down and be replaced. However, there are some factors that contribute to its wearing out or that can cause it to fail prematurely. 

Mechanic checking what causes a stator to fail


As motorcycle owners and riders, this is a factor that we can’t do anything about. All of the parts of a motorcycle, even those designed not to wear out, will be exposed to changing elements and stress over time. The stator is no exception to this. 

Performing routine maintenance and always being mindful of the state of your bike and its components will maximize its life span. Remember that the stator is a core component of the bike’s electrical system. Maintaining the attached parts, like batteries and spark plugs, will be the greatest contributor to ensuring the stator lasts a long time. 

Power Load

The second element that can influence the lifespan of the stator is power load. For many riders, the stock accessories on the bike will simply not be sufficient, so we add extra electronic gadgets like heated grips, GPS units, and even stereos. 

All these accessories will load the bike’s electrical system, putting significantly greater stress on the stator, which is responsible for generating the power they use. Most motorcycles aren’t originally equipped with that many gadgets, and so their electrical systems aren’t designed to handle the added draw of those accessories. 

Repair a Bad Motorcycle Stator

Running anything beyond its intended specifications will cause it to burn out more quickly, including the electrical system. That’s something to keep in mind when thinking about how to customize your bike.

Is it Possible to Repair a Bad Motorcycle Stator?

The stator on your motorcycle is made of several very small, very delicate parts. This means that repairing it yourself will be very time-consuming and is not a low-risk task. Because of the likelihood of failure, it is definitely recommended to take your bike to a professional who can tell you whether the stator can be repaired or will need to be completely replaced.

Frequently Asked Questions

What problems can a bad stator cause?

Because the stator is responsible for generating electrical power for the bike, the problems it causes are also electrical in nature. Minor issues will involve the electrical accessories, such as lights and gauges not working like they are supposed to, while major problems will involve the spark plugs failing to ignite the fuel in the cylinders. This can range from intermittent misfiring to the bike failing to start at all.  

Will a bad stator drain a battery?

A bad stator will not drain the battery itself but instead fails to charge it This means that electrical accessories installed on the bike will draw more power than the stator is generating and ultimately cause the battery to die. 

Will a stator charge the battery at idle?

Technically, yes, the battery will charge while the bike is idling, but extremely slowly. At higher speeds, the electrical system will generate power for the battery and help keep it topped off. Any time the bike is running, the stator is generating power, but it needs to be running at a higher speed to reach its maximum output. 


Today we’ve looked at one of a motorcycle’s most overlooked components: the stator. While most of us don’t put a lot of thought into this piece of the bike’s electrical system, it serves a critical role in keeping our favorite ride running effectively. 

Now, when the gauges start to dim on your bike or you hear the engine start to misfire, you will have a much better idea of what to check out to get back on the road as quickly as possible. 

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Ryan Christian

My lifelong love of everything on wheels began with a dusty old scooter and a set of second hand wrenches. Since then I’ve spent every moment I can spare finding new dirt paths, winding country roads, and long open highways. I write to share my passion with other enthusiasts, and maybe inspire one or two new ones along the way!