Top 10 Most Common Symptoms Of Bad Motorcycle Stator

Top 10 Most Common Symptoms Of Bad Motorcycle Stator

The motorcycle’s charging system consists of a battery, regulator, rectifier, and alternator/Stator which plays a vital role in keeping the motorcycle charged up and running.

A bad motorcycle stator can cause a lot of problems and hinder your riding experience. In this article, you will know the symptoms/signs of a bad motorcycle stator and what are the causes behind each one of them, and how to fix this problem.

Here’s a Quick List For Symptoms Of A Bad Motorcycle Stator

  1. Motorcycle Experiences No Spark Condition
  2. Dimming Of Motorcycle Headlight
  3. Motorcycle Will Misfire
  4. Spark Plug Produces Weak Spark 
  5. No Riding Information On Motorcycle’s Instrument/Gauge Cluster.
  6. Motorcycle Electronic Features Will Not Working Properly
  7. Engine Stalls Frequently
  8. Motorcycle Will Be Harder To Start
  9. The Battery Will Drain Quickly
  10. Motorcycle Performance Drops

Now let’s get into details of each symptom of a bad motorcycle stator.

Symptom No 1: Motorcycle Experiences No Spark Condition

When you start the motorcycle by pressing the starter button, the spark plugs create a spark inside the combustion chamber to ignite the air-fuel mixture and start the combustion process.

And a motorcycle stator provides the power( electric current ) to the spark plugs with the help of a battery and regulator/rectifier.

A bad motorcycle stator that is completely damaged won’t be able to supply a sufficient amount of current to the spark plugs creating a no-spark condition that results in the motorcycle not starting at all.

Symptom No 2: Dimming Of Motorcycle Headlight

Your Motorcycle headlight and indicators need a power supply to work effectively. 

Even when your switch from low beam to high beam or activate motorcycle indicators, a constant steady supply of current is needed.

Though the battery provides power to headlights, the motorcycle’s stator is continuously creating and supplying power to the battery. 

And if there is a problem/issue with your stator, the headlight and indicators will start dimming because of insufficient and unsteady supply of current/power to them.

Symptom No 3: Motorcycle Will Misfire

Spark plugs work in the motorcycle by continuously sparking or firing inside the combustion chamber to ignite the air-fuel mixture.

As you know, spark plugs fire multiple times in a continuous pattern to keep the motorcycle running properly. 

If a stator goes bad, the supply of current that fires/sparks the spark plugs will be unstable and not in a continuous flow causing the motorcycle engine to misfire.

Symptom No 4: Spark Plug Produces Weak Spark 

In a weak spark condition the spark plug fires with less intensity because of an insufficient amount of current/power provided to it by a bad motorcycle stator.

You will experience this while riding too, as the motorcycle will start to buck and bog (jerky movements) because the spark plugs are not operating at their full capacity.

This results in an imbalanced riding experience where the acceleration of the motorcycle is not steady and drops when you roll your motorcycle’s throttle.

Symptom No 5: No Riding Information On Motorcycle’s Instrument/Gauge Cluster

Motorcycle gauges also called instrument cluster shows information such as speedometer, odometer, tachometer, fuel range, engine temperature, and other modern riding features.

To show all the riding data on the front panel screen called instrument cluster/gauge, it needs sufficient electrical power/current supplied to it.

A bad stator causes insufficient or even no supply to the battery to further provide the power to the gauges/instrument cluster to show riding information.

This results in the dimming of lights from motorcycle gauges and stops showing riding information turning into a completely blank screen.

Symptom No 6: Motorcycle Electronic Riding Features Will Not Working Properly

So most of the modern motorcycles come with various riding features such as switchable abs, riding modes, build GPS, automatic suspension adjustment in higher cc motorcycles, and much more. 

Making changes and altering your riding experience at the click of a button on the motorcycle is all handled by the ECU ( Electronic Control Unit ) of the bike.

And the ECU is supplied with a sufficient amount of electric power, which is provided by the motorcycle’s battery and stator.

A bad stator that has problems will not be able to supply electric power to the ECU, causing the motorcycle’s various electronic riding features/functions to stop working.

Symptom No 7: Engine Stalls Frequently

For a motorcycle to run smoothly and steadily it requires a proper ratio of air-fuel mixture and a sufficient amount of electric supply ECU and fuel injection system (at least for modern motorcycles ).

The motorcycle engine will stall if it’s not provided with a steady supply of air and fuel which are handled by a fuel injection system (controlled by ECU) or carburetor

A stator that has gone bad will not be able to provide electric power for the fuel system and spark plugs to maintain a proper combustion process, which will result in the motorcycle’s engine stalling or halting.

Symptom No 8: Motorcycle Will Be Harder To Start

The stator has a vital role in starting the motorcycle since it’s generating electric current/charge and continuously supplying it to the battery, which provides power for the ignition helping the motorcycle to start.

A stator that is in bad condition but not completely damaged and is still somehow working will provide insufficient electric supply to essential parts of the motorcycle, which helps to start the bike.

So due to this irregular insufficient electric power supply, the motorcycle will be harder to start and can take multiple attempts.

Symptom No 9: The Battery Will Drain Quickly

A motorcycle battery can hold a particular amount of charge in it to carry out all the necessary motorcycle functions.

But the battery also needs a constant supply of DC ( direct current )to keep it charged which is provided by the stator and regulator/rectifier of the motorcycle.

The motorcycle stator generates AC ( alternate current ) electric power inside the rotor, which is then supplied to the regulator/rectifier that converts AC power into DC power, this DC power then finally goes to the battery and charges it.

A bad stator will not only stop generating electric power but will also stop further charging the battery, so the motorcycle’s electric functions will solely depend on the battery alone causing it to drain quickly.

Symptom No 10: Motorcycle Performance Drops

This symptom is plain and simple, as you know by now ECU of the motorcycle needs a supply of current that controls the fuel system of the motorcycle.

Bad stator condition causes the supply of current to be irregular and not sufficient to the ECU, fuel system, and spark plugs of the motorcycle causing the imbalance in the air-fuel mixture which results in a drop in the motorcycle’s performance.

This irregular supply of fuel and air to the combustion chamber causes the motorcycle hard to run roughly and with much effort.

Now you know the most common symptoms of a bad stator in motorcycles, but there are also a couple of reasons that can cause the stator to fail.

What Causes A Motorcycle Stator To Fail & How To Fix Them

There are a couple of reasons which are very common to cause a stator to fail, and preventing them is not that hard.

Here are the causes of a motorcycle stator failure 

  1. The Stator Will Wear Out Overtime
  2. Power Overload On Stator
  3. Heat Buildup In Stator Coil Winding

Stator Failure Cause No 1: Stator Will Wear Out Overtime

Motorcycle parts have a certain lifespan to them which can cause them to wear and tear as per your riding style and maintenance routine.

The Stator lasts for a long time but will wear out over time. You will ride your motorcycle in various riding conditions during your ownership period.

A proper maintenance routine can play a good part in extending the longevity of the parts but down the road, it either needs replacement or a maintenance checkup.

How To Fix: This one is pretty evident, overtime stator will wear out but it can take a long time. But when the time comes replace the old stator with a new one.

Stator Failure Cause No 2: Power Overload On Stator

The motorcycle’s battery and stator work in conjunction with each other, where the stator generates and supplies electric charge to the battery, and the battery holds the charge and provides it to the necessary motorcycle parts.

The stator and battery operate at a particular voltage range. 

So whenever additional add-on accessories of a motorcycle that needs an electric charge to operate exceed the operating voltage range of the stator and battery will cause a power overload on the motorcycle stator causing it to fail.

How To Fix: Power overload on the stator can be easily avoided, just add a few necessary electric charge-dependent accessories to the motorcycle and check their amperage/voltage requirements to see it doesn’t cause overload on your motorcycle battery and stator.

Stator Failure Cause No 3: Heat Buildup In Stator Coil Winding

The building up of heat in the stator can be caused due to the engine running hot.  

Changing your old coolant, and engine oil and having the proper maintenance routine will keep the engine running smoothly and at an appropriate temperature.

This build-up o heat in the stator coil causes the winding of the copper wire to break or come loose.

So follow a holistic maintenance ritual for your motorcycle to avoid overheating of the engine which can cause the stator failure.

How To Fix: Maintenance is a crucial aspect of a motorcycle’s performance and longevity. Engine overheating be easily avoided by having a proper coolant and engine oil change routine.

Cleaning the motorcycle and having periodic checking of parts that needs replacement or a little cleanup can go a long way.

These were the most common and major causes of stator to fail, now you know what to look out for and how to fix it and avoid them.

Can You Repair A Motorcycle Stator?

Repairing a stator is quite a complicated task that should be handled with care and expertise. 

So the question is can you repair a motorcycle stator? The motorcycle stator repair should be repaired by a professional mechanic because the repair process needs specialized tools and expertise for the copper coil and multiple connectors of the stator to be examined and replaced or repaired if necessary.

The stator is very intricately designed and has multiple wiring connections which have to be connected to the right connector pins.

If you have no experience repairing a motorcycle stator, then let the professional mechanic repair it properly for you. You don’t want additionally damaged to the motorcycle because of the bad repairing method of the stator.

You can go through the whole process of removing the epoxy from the wire winding and then cleaning the wire’s housing/pole assembly. After removing the winding, you have to examine the copper wire for any kind of damage then install/wound the new copper wire onto the poles correctly so wouldn’t come off.

Then you have to insulate it again with epoxy chemical and the most part is to connect the wire ends to the right connectors/phases.

During this whole process if you don’t have experience chances are you will get it wrong and can cause damage to the motorcycle.

The stator is one of the core parts of your motorcycle to keep it running. So handling it with care and spending your hard-earned money ( Dollars/Rupees/Pounds/Peso ) on the repair or replacement is worth it. Cause you don’t want to pay for any kind of damage caused due to following a wrong process or making any mistake while repairing it by yourself.


The Stator plays a vital role in running the motorcycle, and repairing it by yourself without any expertise can cause damage to the motorcycle as the process of repairing the stator is complex and should be handled with care.

Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts