Symptoms of A Bad Ignition Coil on A Motorcycle

Motorcycle performance depends on the ignition coil. The ignition system’s spark generator ignites the engine’s air-fuel mixture. Motorcycles may not start or run poorly without an ignition coil. Thus, knowing the ignition coil’s importance and its symptoms is essential for motorcycle performance and safety.

The ignition coil is a key component in your motorcycle’s ignition system. Its main purpose is to convert the motorcycle’s low-voltage power supply into the high-voltage electrical spark needed to ignite the engine’s air-fuel mixture.

This combustion process creates the power necessary to move the motorcycle. Without the ignition coil, this essential process couldn’t occur, and your motorcycle wouldn’t function.

How the Ignition Coil Works to Generate Spark

An ignition coil operates using the principles of electromagnetic induction. It has two sets of windings: a primary winding with a few thick wire coils and a secondary winding with thousands of thinner coils.

When the ignition key is turned, electricity from the motorcycle’s battery flows through the primary winding, creating a magnetic field. When the current is interrupted (by the ignition control module, based on input from sensors), the magnetic field collapses quickly. This sudden collapse induces a high voltage in the secondary winding due to its many turns of wire.

A spark plug wire delivers up to 50,000 volts to the spark plug. The high voltage jumps the gap at the spark plug, creating the spark needed to ignite the air-fuel mixture in the combustion chamber. The resulting combustion pushes the piston down, turning the crankshaft, and propelling the motorcycle forward.

Common Symptoms of a Bad Ignition Coil

Ignition coil problems can cause a variety of symptoms that range from mild to severe. Noticing these symptoms early and addressing them can prevent further damage to your motorcycle’s engine or electrical system.

1. Engine Misfires

Rough Idling and Stalling:

A faulty ignition coil can disrupt the normal engine combustion process, leading to unburned fuel in the engine and causing the motorcycle to idle roughly or stall. You may notice the engine shaking while your motorcycle is idle or even see it stop running entirely, especially at low speeds.

Hesitation and Power Loss During Acceleration:

A bad ignition coil can also cause your motorcycle to hesitate or lose power when you’re accelerating. The engine may stutter or seem less responsive than usual, especially when you’re trying to increase speed.

2. Difficulty Starting the Motorcycle

If your ignition coil isn’t working, it may not spark the engine. This can cause the motorcycle to require multiple attempts to start, or it may feel unusually difficult to start.

In severe cases, a completely failed ignition coil may not provide any spark at all, preventing the engine from starting.

3. Decreased Fuel Efficiency

If the ignition coil fails, the engine may burn fuel inefficiently, reducing mileage and fuel efficiency.

A failing ignition coil may also cause the motorcycle to produce unusual or excessive exhaust emissions due to incomplete fuel burning.

4. Engine Performance Issues

An ineffective ignition coil can lead to a lack of power and poor throttle response, causing the motorcycle to feel sluggish or slow to respond to input.

If the ignition coil is sending inconsistent voltage to the spark plugs, it could lead to irregular engine RPM or uncontrolled acceleration, commonly known as surging.

5. Electrical Problems

Dim or Flickering Lights: If the ignition coil is drawing too much or too little power, it can lead to dim or flickering lights on your motorcycle.

Electrical System Malfunctions: A failing ignition coil can also cause various electrical system malfunctions, including problems with the dashboard lights, the radio, or other electrical components.

Check your motorbike if you notice any of these symptoms. Ignition coil problems can lead to more serious issues if left unchecked.

Diagnostic Techniques

Identifying a faulty ignition coil can be difficult, but there are several methods.

1. Visual Inspection

Begin by inspecting the ignition coil for any obvious signs of physical damage, such as cracks, burn marks, or signs of arcing. Corrosion or rust on the coil could also be a sign of problems.

Also, check the electrical connections to the coil. Loose or corroded connectors can disrupt the coil’s operation. Check for damaged or frayed wiring, as it can also lead to faulty operation of the coil.

2. Resistance Testing

A multimeter is used to test ignition coils. This is done by placing the multimeter’s probes on the coil’s primary and secondary terminals and observing the resistance readings.

These readings should then be compared with the manufacturer’s specifications. If the readings are outside the specified range, it’s a clear sign that the ignition coil is faulty.

3. Spark Testing

Spark testing is another effective way to assess the health of your ignition coil. This involves using a spark tester – a device that’s hooked to the spark plug wire and grounded to the engine – while the engine is cranked.

A bright blue spark should appear every firing cycle. If the spark is weak (yellow or orange), inconsistent, or absent, the ignition coil is malfunctioning.

Remember that working with your vehicle’s ignition system can be dangerous due to high voltage. A professional mechanic should handle these repairs if you’re not skilled.

Causes of Ignition Coil Failure

Ignition coils are generally durable components, but they can fail for several reasons, some of which include:

1. Overheating

Excessive heat can be a significant enemy of ignition coils. If your coil is situated near a heat source such as the engine or exhaust and it isn’t adequately shielded, it can overheat, causing the insulation around the coil windings to degrade and eventually fail.

Your motorcycle’s cooling system may malfunction, causing engine heat and coil overheating. Regular maintenance of your motorcycle’s cooling system can help prevent this problem.

2. Voltage Spikes or Surges

Voltage spikes or surges in your motorcycle’s electrical system can cause ignition coil failure. A faulty voltage regulator or other electrical system issues may cause overvoltage, damaging the coil.

Jump-starting or charging your motorcycle improperly can also lead to voltage spikes that can damage the ignition coil. Use these devices according to the manufacturer’s instructions.

3. Age and Wear

Like any other component of your motorcycle, ignition coils can wear out over time. Age, vibrations, and high operating temperatures can cause the insulation on the coil’s windings to degrade, leading to coil failure.

Extreme weather conditions, especially moisture and salt in colder climates, can corrode the ignition coil and its connectors, leading to failure over time.

Being aware of these potential causes can help you prevent ignition coil failure and maintain the performance and reliability of your motorcycle.

Replacement and Maintenance

Replace your motorcycle’s ignition coil if it’s the problem. Along with replacement, understanding how to maintain the new coil will be crucial in preventing future issues.

Steps to Replace a Faulty Ignition Coil

Step 1. Proper Disconnection of Electrical Connections

Start by disconnecting your motorcycle’s battery to avoid any electrical mishaps. Then, locate your ignition coil (or coils if your bike has more than one). It’s typically a small, cylindrical component with an insulated wire leading to the spark plug and a smaller wire connected to the ignition system. After locating it, disconnect the wires attached to the ignition coil. Be careful not to pull on the wires themselves; instead, disconnect at the plugs.

Step 2. Installation of the New Coil and Testing

Replace the old coil with the new one. Make sure it’s secured. Then, reconnect the wires to the new coil. Once everything is connected and secured, reconnect the motorcycle’s battery and start the engine to test the new coil. If the bike starts and runs well, you’ve successfully replaced the ignition coil.

2. Preventive Measures to Extend Ignition Coil Lifespan

One way to prolong the life of your ignition coil is to regularly maintain your motorcycle’s electrical system. Make sure all connections are clean, secure, and free of corrosion. Replace a damaged coil immediately.

Try to protect the ignition coil from exposure to excessive heat and moisture. If your motorcycle’s cooling system is functioning properly, it can help reduce heat exposure to the coil. If you often ride in a wet climate, make sure the coil and its connectors are adequately protected from water intrusion.

It’s possible to replace the ignition coil yourself, but it’s complicated and requires technical knowledge. If you’re not confident, hire a mechanic to replace it safely and correctly.

Frequently Asked Questions (FAQs)

1. Can a bad ignition coil cause engine damage?

Yes, a bad ignition coil can potentially cause engine damage over time. Misfires caused by a faulty ignition coil can result in unburned fuel entering the exhaust system, which can damage the catalytic converter. It can also lead to excessive fuel in the combustion chamber, causing harm to the engine’s components due to an incorrect air-fuel mixture.

2. How often should the ignition coil be replaced?

There isn’t a set schedule for replacing ignition coils because they can potentially last the lifetime of the motorcycle under ideal conditions. However, heat, vibration, and normal wear and tear can eventually lead to coil failure. As part of your regular maintenance, inspect them and replace them if they’re worn or damaged.

3. Can I replace the ignition coil myself, or should I seek professional help?

If you’re mechanically inclined and have some experience with motorcycle maintenance, you may be able to replace the ignition coil yourself. However, the process can be complex, and it’s crucial to disconnect the battery and handle electrical components safely. If you’re uncomfortable with this work or unsure if the ignition coil is the issue, consult a mechanic.

4. Are there any temporary solutions to a bad ignition coil?

There are no reliable temporary solutions for a bad ignition coil. If the coil fails, it can cause performance issues, engine damage, and even a breakdown. If your ignition coil is malfunctioning, replace it immediately.


Understanding the signs of a faulty ignition coil can save you from unnecessary breakdowns and expensive repairs down the line. Key symptoms to watch out for include engine misfires, difficulty starting your motorcycle, decreased fuel efficiency, overall engine performance issues, and various electrical problems.

Ignition coil issues can cause serious engine damage if left unchecked. These issues can also lower your motorcycle’s performance and make riding unsafe.

Check your motorcycle’s ignition coil and electrical system regularly and replace it if it’s worn or damaged. If you’re not comfortable replacing an ignition coil yourself, it’s fine to get help.

By maintaining your ignition coil, you’ll prolong your motorcycle’s lifespan and performance, making rides safer and more enjoyable.