Main points
- Ignition coils are vital components in a motorcycle’s electrical system, responsible for generating the high-voltage spark that ignites the fuel-air mixture in the engine.
- A weak or faulty ignition coil may not generate enough voltage to create a strong spark, leading to difficulty starting or preventing the engine from starting altogether.
- A faulty ignition coil can cause the spark to occur at the wrong time, leading to backfiring through the intake or exhaust system.
Ignition coils are vital components in a motorcycle’s electrical system, responsible for generating the high-voltage spark that ignites the fuel-air mixture in the engine. Faulty ignition coils can lead to a range of problems, from poor engine performance to complete failure. Testing ignition coils is a crucial diagnostic step to ensure your motorcycle runs smoothly and efficiently.
Understanding Ignition Coils
Ignition coils work by converting the low-voltage electrical current from the battery into a high-voltage pulse that travels through the spark plug wire and ignites the spark plug. They consist of a primary winding with a few hundred turns of thick wire and a secondary winding with thousands of turns of thin wire.
Symptoms of a Faulty Ignition Coil
- Hard starting or no start: A weak or faulty ignition coil may not generate enough voltage to create a strong spark, leading to difficulty starting or preventing the engine from starting altogether.
- Rough idling or misfiring: A malfunctioning ignition coil can cause the engine to run erratically or misfire, especially at low RPMs or under load.
- Reduced engine power: A weak ignition coil can limit the amount of spark energy delivered to the spark plugs, resulting in reduced engine power and acceleration.
- Backfiring: A faulty ignition coil can cause the spark to occur at the wrong time, leading to backfiring through the intake or exhaust system.
- Overheating: Excessive heat can damage the insulation on the ignition coil windings, leading to shorts and reduced performance.
Testing Ignition Coil Motorcycle
1. Visual Inspection
- Start by visually inspecting the ignition coil for any cracks, burns, or loose connections.
- Check the spark plug wires and connectors for any damage or corrosion.
- Look for any signs of overheating, such as discoloration or melted plastic.
2. Ohmmeter Test
- Use an ohmmeter to test the resistance of the primary and secondary windings.
- For the primary winding, connect the ohmmeter leads to the two terminals on the coil. The resistance should be within the manufacturer’s specifications, typically between 0.5 and 2 ohms.
- For the secondary winding, connect one lead to the high-voltage output terminal and the other to the ground terminal. The resistance should be in the range of 5,000 to 20,000 ohms.
3. Spark Test
- Connect a spark tester between the spark plug wire and the spark plug.
- Crank the engine over.
- If the ignition coil is functioning properly, you should see a strong blue spark at the spark tester.
- A weak or intermittent spark indicates a potential problem with the ignition coil.
4. Multimeter Test
- Set the multimeter to the AC voltage range.
- Connect the positive lead to the high-voltage output terminal and the negative lead to the ground terminal.
- Crank the engine over.
- You should see a voltage reading of at least 10,000 volts. A lower reading indicates a weak or faulty ignition coil.
5. Oscilloscope Test
- An oscilloscope can provide a more detailed analysis of the ignition coil’s performance.
- Connect the oscilloscope to the high-voltage output terminal and the ground terminal.
- Crank the engine over.
- The oscilloscope should display a waveform with a sharp rise and fall. A distorted or weak waveform indicates a problem with the ignition coil.
Replacing an Ignition Coil
If the tests confirm a faulty ignition coil, it must be replaced.
- Disconnect the negative battery terminal.
- Locate the ignition coil and remove the spark plug wires and electrical connectors.
- Unscrew the bolts or screws holding the ignition coil in place.
- Carefully remove the old ignition coil and install the new one.
- Reattach the spark plug wires and electrical connectors.
- Tighten the bolts or screws to secure the ignition coil.
- Reconnect the negative battery terminal.
Troubleshooting Common Ignition Coil Problems
- Weak spark: Check the spark plug wires, spark plugs, and ignition coil connections.
- No spark: Inspect the battery, ignition switch, and wiring harness for any faults.
- Intermittent spark: Look for loose connections, damaged wires, or a faulty ignition module.
- Overheating: Ensure proper ventilation around the ignition coil and check for any signs of excessive heat.
Final Thoughts
Testing ignition coils is a crucial diagnostic step to ensure your motorcycle’s electrical system is functioning properly. By following the steps outlined in this guide, you can identify and replace faulty ignition coils, restoring your motorcycle’s performance and reliability.
Remember, regular maintenance and proper troubleshooting can help prevent ignition coil problems and keep your motorcycle running smoothly for years to come.
Questions We Hear a Lot
Q: How often should I test my ignition coils?
A: It is recommended to test your ignition coils every 10,000 to 15,000 miles or as per the manufacturer’s recommendations.
Q: Can I test ignition coils without an ohmmeter or multimeter?
A: Yes, you can perform a spark test using a spark tester to check for a visible spark. However, this method does not provide a comprehensive evaluation of the ignition coil’s performance.
Q: What causes ignition coils to fail?
A: Ignition coils can fail due to a variety of reasons, including overheating, excessive voltage, mechanical damage, and wear and tear over time.