Harley Davidson Ignition Coil Problems: What To Do, How and When

Last Updated on December 13, 2023 by Pittalks

Harley Davidson motorcycles are renowned for their robust engines and smooth rides. Nonetheless, like any mechanical device, they are not immune to issues over time. One of the most prevalent problems encountered involves the ignition coil, a critical component in the motorcycle’s ignition system. This article will delve into the symptoms of a bad ignition coil, how to diagnose and fix the problem, tips for preventing ignition coil issues, and answers to frequently asked questions.

What Are The Common Harley Davidson Ignition Coil Problems?

Ignition coils are integral to the functioning of Harley Davidson motorcycles. They transform the low voltage from the battery into a much higher voltage required to ignite the fuel and start the engine. When these coils start failing, it can lead to various issues with your motorcycle’s performance. Here are some of the most common problems associated with Harley Davidson ignition coils:

1. Poor fuel economy: A faulty ignition coil can cause your Harley Davidson to consume more fuel than usual, leading to increased fuel costs.
2. Backfiring: Frequent backfiring can indicate a failing ignition coil. The coil may fail to provide sufficient voltage for the spark plugs, causing the engine to backfire.
3. Stalling: A defective ignition coil can cause your motorcycle to stall while you’re riding, which can be dangerous, especially at high speeds.
4. Difficulty starting: If your Harley Davidson is struggling to start, it could be due to a bad ignition coil.
5. Rough idling: A malfunctioning ignition coil can lead to rough idling, with the engine running unevenly or hesitating when at a stop.
6. Engine misfiring: Engine misfiring is another common symptom of a bad ignition coil, causing the engine to run unevenly or even stall.

Symptoms of A Bad Ignition Coil

Recognizing the signs of a bad ignition coil is crucial for maintaining the performance of your Harley Davidson. Here are some symptoms to look out for:

1. Poor Fuel Efficiency: A faulty ignition coil can lead to your Harley Davidson consuming more fuel than typically required. This results in reduced mileage and increased fuel costs.
2. Frequent Backfiring: If your motorcycle is backfiring more often, it might be due to a malfunctioning ignition coil. When the coil fails to provide enough voltage for the spark plugs, the engine can backfire.
3. Stalling and Difficulty Starting: A failing ignition coil can cause your motorcycle to stall while you’re riding or make it difficult for your motorcycle to start.
4. Rough Idling: A defective ignition coil can result in rough idling, with your engine running unevenly or hesitating when you’re at a stop.
5. Engine Misfiring: Engine misfiring is another symptom of a faulty ignition coil. If your ignition coil isn’t functioning correctly, your engine can misfire, leading to uneven running or stalling.

How To Fix and Diagnose

1. Disconnect the battery: Before you start, ensure you disconnect the negative terminal on your battery to prevent any electrical mishaps.
2. Locate the faulty coil: Find the coil that needs to be replaced and disconnect the cable leading to it.
3. Remove the faulty coil: Unscrew the bolts holding the coil in place and remove the faulty coil from the engine bay.
4. Install the new coil: Install the new coil following the correct installation process. Ensure the new ignition coil is compatible with your engine.
5. Reconnect the battery: Once the new coil is installed, reconnect the battery and test the motorcycle to ensure the problem has been resolved.

Preventing Ignition Coil Problems

Ignition coil problems can be prevented through regular maintenance and inspection of your Harley Davidson. Here are some tips:

1. Regular inspection: Regularly inspect your ignition coil for any signs of wear or damage.
2. Replace old coils: Ignition coils can wear out over time, so it’s a good idea to replace them as part of your regular maintenance schedule.
3. Use quality parts: When replacing your ignition coil, ensure you use high-quality parts compatible with your Harley Davidson.

What Causes These Issues?

Ignition coil problems can be caused by several factors, including:

1. Age and wear: Ignition coils can wear out over time due to constant heating and cooling.
2. Heat and vibration: The heat and vibration from your motorcycle’s engine can lead to ignition coil problems.
3. Poor maintenance: Regular maintenance is crucial to keep your ignition coil in good condition.

Has Harley Improved Their Ignition Coils?

Harley Davidson has made significant improvements to their ignition coils over the years. The introduction of electronic ignition in the early 1980s helped to increase reliability and reduce maintenance needs. More recently, the use of Coil on Plug (COP) units, where the coils are positioned directly on top of each spark plug, has further improved performance by reducing voltage loss and improving timing.

How Frequently Should You Replace Your Ignition Coils?

The frequency of ignition coil replacement varies depending on your motorcycle’s make and model, how often you ride, and the conditions in which you ride. However, as a general rule, it’s a good idea to inspect your ignition coil at least once a year and replace it every 70,000 to 100,000 miles.

Are Ignition Coils The Same As Coil Packs?

Ignition coils and coil packs serve the same basic function – transforming the battery’s low voltage into the high voltage needed to ignite the fuel – but they are not the same thing. An ignition coil is a single unit that serves all the spark plugs, while a coil pack contains multiple ignition coils, each serving one or two spark plugs.

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