6 Best Spark Plugs For Harley-Davidson Motorcycles 2025 in the United States

The NGK Iridium IX DCPR7EIX spark plugs are designed to fit Harley Davidson Twin Cam motorcycles from 1999 to 2016. These spark plugs come pre-gapped, making installation straightforward, especially for those who prefer not to adjust the gap size themselves. The use of iridium for the electrode material is a significant advantage, as it reduces the voltage requirement and extends the life of the ignition system, which could result in fewer maintenance intervals and potentially lower long-term costs.

The heat range of these plugs is suitable for a wide range of riding conditions, making them a versatile option for different climates and riding styles. The 12mm thread size and specific reach ensure compatibility with the specified Harley Davidson models, ensuring a good fit and effective performance. Additionally, the new metal shell plating enhances anti-corrosion properties, which is beneficial for longevity and durability, especially in varying weather conditions.

These spark plugs are primarily recommended for motorcycle enthusiasts who own Harley Davidson Twin Cam models within the specified years. Riders of other motorcycle models might not find these plugs suitable for their needs. While the higher price point of iridium plugs can be a drawback for some buyers, the benefits in terms of performance and longevity often justify the expense. The NGK Iridium IX DCPR7EIX spark plugs are a reliable choice for Harley Davidson Twin Cam owners looking for durable and efficient spark plugs.

The BDFHYK Set of 4 Iridium Spark Plugs is designed for Harley-Davidson Sportster 1200 (1988-2016) and Sportster 883 (1986-2016) models. One of its strongest features is the iridium core material, which is known for superior ignition performance and durability. This material helps in achieving quicker and more sensitive ignition jumping, which can enhance power performance significantly. The spark plugs are OE standard and TS16949 certified, ensuring they meet high quality and performance standards.

Additionally, the insulators made from isostatic ceramics offer high density, strength, and good insulation, which contributes to the product's reliability. However, users need to carefully check compatibility with their specific Harley-Davidson model and OE part number to avoid any installation issues. The product has a solid customer rating of 4.4 out of 5 stars from 116 reviews, indicating general satisfaction.

On the downside, being a vehicle-specific product, it may not be suitable for users with different motorcycle brands or models. The package dimensions and weight suggest it is portable and easy to handle. Despite being a bit niche, this set could be a great fit for Harley-Davidson Sportster owners looking for high-performance spark plugs with excellent durability.

The CNPAPC Upgrade Double Iridium IX Spark Plugs are a solid choice for Harley Davidson motorcycles, specifically models from 1999-2016 Twin Cam, among others. A significant strength is the use of double iridium for the electrode material, known for its high melting point and durability, making these spark plugs long-lasting and reliable. This means you'll likely replace them less often compared to standard plugs.

The spark plugs also promise improved fuel efficiency and better engine performance, which can be appealing for performance enthusiasts looking to optimize their bikes. The thread size is 12, and the gap size is 0.8 millimeters, which are standard and should fit well in the specified Harley Davidson models. However, some users might find that their performance enhancements may be marginal compared to standard plugs, especially if their riding style doesn't push the bike's limits.

Additionally, while they are not the cheapest option on the market, the longevity offered by double iridium can make up for the higher initial cost. The product also comes with a 12-month warranty, which adds a layer of assurance for buyers. These spark plugs are best suited for Harley Davidson owners who prioritize durability and performance and are willing to invest a bit more upfront for long-term benefits.