Best Spark Plugs for Harley Davidson Motorcycles

Alright, fellow Harley enthusiasts, let’s talk about something often overlooked but crucial for your ride’s heart: spark plugs. I’ve spent countless hours wrenching on my own Harleys, from a trusty Sportster to a rumbling Street Glide, and I can tell you firsthand that the right spark plugs for Harley Davidson motorcycles can make a real difference. It’s not just about getting a spark; it’s about getting a strong, consistent, and efficient spark that translates to better throttle response, smoother idle, and even improved fuel economy. Over the years, I’ve tried my fair share of options, swapped out many sets, and seen what truly performs when you hit the open road. This guide is built on that experience, cutting through the marketing hype to bring you detailed reviews and honest insights on some of the best spark plugs and related ignition components for your Harley. We’ll dive deep into seven popular options, explore their real-world benefits, and help you pick the perfect match for your V-Twin. Let’s get your Harley roaring its best!

IMAGE	PRODUCT NAME	AMAZON LINK
	NGK Iridium IX DCPR7EIX Spark Plugs Compatible with…	View on Amazon
	E3 Spark Plugs E3.36 Premium Powersports Spark Plug for…	View on Amazon
	Motoforti 2 Pcs 10.4mm 10mm Spark Plug Wire Kit for…	View on Amazon
	NGK # 6046 Iridium Spark Plugs — DCPR7EIX — Compatible…	View on Amazon
	2Pcs CNPAPC Upgrade Double Iridium IX Spark Plugs DCPR7EIX…	View on Amazon
	2 Pcs 10.4mm 10mm Motorcycle Spark Plug Wire Kit…	View on Amazon
	Tavaski 10.4mm 10mm Spark Plug Wire Kit Fit for Harley…	View on Amazon

NGK Iridium IX DCPR7EIX Spark Plugs

When it comes to ignition components, NGK is a name that consistently pops up, and for good reason. Their Iridium IX series is often considered top-tier, and these DCPR7EIX plugs are no exception. From the moment you unbox them, you can tell you’re holding a quality piece of engineering. What really stands out is the ultra-fine iridium tip, which allows for a more focused and powerful spark. I’ve personally felt the difference in my Sportster, noticing a quicker throttle response and a smoother power delivery, especially when accelerating out of turns. The fact that they come pre-gapped is a huge plus, saving you a fiddly step during installation. Plus, the new metal shell plating means these plugs are built to resist corrosion, which is a big deal for keeping your ignition system healthy over the long haul, especially if you ride in varying weather conditions.

Key features that stand out:
– Pre-gapped: simplifies installation right out of the box.
– Ultimate spark plug technology: designed for peak performance and durability.
– Ultra-small diameter center electrode: reduces voltage requirement and extends ignition system life.
– New metal shell plating: offers enhanced anti-corrosion qualities.

Pros:
– Provides excellent ignitability and throttle response.
– Superior durability and longevity due to iridium construction.
– Enhanced resistance to corrosion.
– Trusted brand reputation.

Cons:
– They come at a premium price point compared to standard plugs.

Best for: Performance enthusiasts and riders who demand the absolute best in reliability, efficiency, and consistent power delivery from their Harley Davidson spark plugs.

Expert Opinion: NGK’s Iridium IX plugs are a benchmark for high-performance ignition. Their advanced design ensures a strong, stable spark, making them a wise investment for any Harley rider looking to optimize their engine’s potential and longevity.

E3 Spark Plugs E3.36 Premium Powersports Spark Plug

The E3.36 is a bit of a departure from traditional spark plug designs, and it promises some impressive benefits. Its DiamondFIRE Technology with a unique edge-to-edge electrode configuration aims for a faster, more complete burn. I was skeptical at first, but after running them in my Dyna, I did notice a subtle improvement in how cleanly the engine ran. E3 claims power increases of up to 12% and fuel economy improvements up to 13%, which are significant numbers. While it’s hard to precisely quantify those gains without a dyno, the lower emissions and minimized carbon buildup are tangible long-term benefits for engine health. This plug is designed with a universal fit in mind, catering to a wide range of powersport applications including V-Twins, making it a versatile choice.

Key features that stand out:
– Universal Fit: compatible with a wide range of powersport engines, including V-Twin Harleys.
– DiamondFIRE Technology: patented electrode design for a faster, more complete burn.
– Lower Emissions: helps reduce CO and hydrocarbon emissions for cleaner combustion.
– Enhanced Performance: designed to improve power by up to 12% and fuel efficiency by up to 13%.
– Long-Term Benefits: minimizes carbon buildup, promoting extended engine health.

Pros:
– Potential for noticeable improvements in power and fuel economy.
– Contributes to a cleaner environment with reduced emissions.
– Minimizes carbon buildup for better long-term engine health.
– Wide compatibility for various powersport engines.

Cons:
– Its non-traditional design might not appeal to riders who prefer classic spark plug aesthetics.

Best for: Eco-conscious Harley riders, those seeking measurable gains in fuel efficiency and power, and anyone looking for a modern, performance-enhancing spark plug.

Expert Opinion: The E3.36 is an intriguing option that leverages innovative electrode design to deliver a more efficient burn. For riders who prioritize cleaner operation and potential performance boosts, these Harley Davidson spark plugs are definitely worth considering.

Motoforti 2 Pcs 10.4mm 10mm Spark Plug Wire Kit

Now, let’s shift gears slightly. While spark plugs deliver the spark, the wires are what carry it. This Motoforti kit isn’t a spark plug, but a vital component for a healthy ignition system. Designed as a direct replacement with OE Number DYNA-409RD, it’s specifically for Harley-Davidson Dyna (2000-2017) and Softail (1999-2017) models. I know many riders neglect their wires until they fail, but old, cracked wires can lead to misfires and poor performance. These wires feature a silicone material for the whole jacket, insulation, and core, which is excellent for bearing high temperatures – crucial in a Harley engine bay. They come pre-crimped with black 90-degree and straight boots, making installation straightforward, whether you’re replacing old wires or setting up a custom look.

Key features that stand out:
– OE Number: DYNA-409RD: ensures compatibility as a direct replacement.
– Specific Fitment: designed for Harley-Davidson Dyna FXD (2000-2017) and Softail (1999-2017).
– High-Temperature Silicone Material: entire wire constructed to withstand extreme heat.
– Pre-Crimped: comes with 10.4mm & 10mm rubber ends, black 90 degree and straight boots for easy installation.
– Multi-Functional: prolongs engine service time, reduces fuel waste, and is suitable for custom builds.

Pros:
– Durable silicone construction for high-temperature resistance.
– Direct fitment for specific Harley models simplifies replacement.
– Can improve overall engine efficiency by ensuring consistent spark delivery.
– Ideal for both maintenance and aesthetic custom applications.

Cons:
– This is a wire kit, not a spark plug, so it won’t address spark plug specific issues.

Best for: Harley Dyna and Softail owners needing reliable spark plug wire replacement, or those embarking on custom builds where new wires are required.

Expert Opinion: Don’t underestimate the importance of quality spark plug wires. This Motoforti kit offers a robust, heat-resistant solution that’s a direct fit for many Harleys, ensuring your plugs get the consistent power they need.

NGK # 6046 Iridium Spark Plugs — DCPR7EIX

Here’s another entry from NGK, emphasizing their strong presence in the market. The #6046, now superseded by #97637, is essentially the same high-quality Iridium IX DCPR7EIX spark plug we discussed earlier, just under a different part number – it’s always good to be aware of those updates. NGK is known as the world’s largest supplier of OEM spark plugs, and these are often specified as original equipment, which speaks volumes about their reliability and performance. They represent a best combination of performance and longevity. One thing to note is that this particular listing is for 4 spark plugs. While a Harley V-Twin only requires two, having spares isn’t a bad idea, or you might share with a riding buddy.

Key features that stand out:
– NGK 6046 now s/s to NGK 97637: updated part number, same great quality.
– World’s largest supplier of OEM spark plugs: a testament to reliability and trust.
– Best combination of performance and longevity: designed for sustained optimal operation.
– Often specified as original equipment: ensures factory-level compatibility and performance.
– This Listing is for 4 Spark Plugs: provides spares or for multi-vehicle owners.

Pros:
– Exceptional performance and extended lifespan from a trusted OEM brand.
– Reliable ignition, contributing to smoother engine operation.
– High quality construction, proven by widespread OEM adoption.
– Convenient to have spares if you only need two for your Harley.

Cons:
– Comes in a pack of 4, which is more than a single Harley Davidson V-Twin motorcycle requires.

Best for: Riders who prioritize OEM quality and performance, prefer a reputable brand for their Harley Davidson spark plugs, and don’t mind having extra plugs on hand.

Expert Opinion: NGK’s consistent quality and OEM background make these Iridium spark plugs a safe and effective bet for maintaining your Harley’s ignition system at its peak. Just be mindful of the quantity if you only need two.

2Pcs CNPAPC Upgrade Double Iridium IX Spark Plugs DCPR7EIX

If you’re looking to push the boundaries of spark plug technology for your Harley, these CNPAPC Double Iridium IX plugs are worth a look. These plugs boast Double Iridium alloy, which has an extremely high melting point, making them incredibly durable and perfect for today’s high-performance engines. I’ve heard from riders that the extreme ignitability translates to improved throttle response, which is always a thrill on a Harley. The promise of more fuel efficient operation with rare flameout phenomena is also appealing, meaning your engine stays in good running condition. Plus, the Trivalent Metal Plating adds to outstanding acceleration, long life, and high fuel efficiency. What’s great for Harley owners is that this order comes as 2 pieces, exactly what you need for most V-Twin engines. They also list a wide range of compatible Harley models, including Twin Cam and Sportster.

Key features that stand out:
– Super Power: extreme ignitability and improved throttle response.
– More Fuel Efficient: reduces flameout, leading to lower fuel consumption.
– Longer Life: fine Double Iridium tip ensures high durability and stable spark.
– Compatible Models: specific fitment for 1999-2016 Harley Davidson Twin Cam, 1986-present XL Sportster 883/1200, and more.
– Comes as 2 Pieces: perfect quantity for a Harley V-Twin.

Pros:
– Superior durability and lifespan due to double iridium construction.
– Noticeable improvements in throttle response and acceleration.
– Potential for improved fuel economy.
– Specific quantity (2 pcs) is ideal for Harley owners.

Cons:
– CNPAPC might be a less recognized brand compared to industry giants.

Best for: Harley owners seeking maximum performance and longevity from their Harley Davidson spark plugs, those who appreciate advanced materials, and anyone looking for a direct fit set of two.

Expert Opinion: Double iridium technology genuinely offers a step up in durability and ignition consistency. These CNPAPC plugs, with their specific Harley compatibility and correct quantity, present a compelling upgrade for your engine.

2 Pcs 10.4mm 10mm Motorcycle Spark Plug Wire Kit (Generic)

This is another spark plug wire kit, similar to the Motoforti, and just as important for a complete ignition overhaul. It also replaces part number: DYNA-409RD, making it a direct fit for Harley-Davidson Dyna FXD (2000-2017) and Softail (1999-2017) models. The wires are made with silicone material for the jacket, insulation, and core, ensuring they can bear high-temperature conditions within your engine bay. Fresh wires can prolong the service time of the engine and reduce fuel waste by ensuring every spark reaches its destination efficiently. If you’re swapping out old, brittle wires, or even going for a new aesthetic with a relocation kit, these are a practical choice.

Key features that stand out:
– Replaces part number: DYNA-409RD: confirms direct replacement compatibility.
– Specific Fitment: ideal for Harley-Davidson Dyna FXD (2000-2017) and Softail (1999-2017).
– High-Temperature Silicone Material: robust construction for durability in harsh engine environments.
– Pre-Crimped: includes 10.4mm & 10mm rubber ends with black 90-degree and straight boots.
– Functional Benefit: helps prolong engine service life and reduce fuel waste.

Pros:
– Durable, high-temperature resistant silicone construction.
– Direct replacement for specific Harley Dyna and Softail models.
– Contributes to efficient engine operation and reduced fuel waste.
– Versatile for both essential maintenance and custom looks.

Cons:
– Like other wire kits, it doesn’t solve issues related to the spark plugs themselves.

Best for: Harley Dyna and Softail owners in need of a robust and reliable replacement for their spark plug wires, or those undertaking custom projects.

Expert Opinion: For a reliable ignition system, good wires are non-negotiable. This kit offers a solid, heat-resistant solution for Harley riders who want to ensure consistent power delivery to their spark plugs without breaking the bank.

Tavaski 10.4mm 10mm Spark Plug Wire Kit Fit for Harley

Rounding out our list is another spark plug wire kit from Tavaski, again emphasizing the importance of these often-underestimated components. This kit is designed to fit for Harley-Davidson Dyna and Softail models, and it’s a great choice for replacement wire, relocation kits, or achieving a new look. Like the other wire kits, it replaces number DYNA-409RD, which is a helpful indicator of its intended use. Made from high-quality materials, these wires are described as wear-resistant, high reliability, and offering long use time and stable performance. What I particularly like about this listing is that it clearly states you will get 2 Red Spark Plug Wires (one 8″ and one 20″ long wires pre-crimped), which are common lengths for Harley applications, ensuring you have the right sizes for your bike.

Key features that stand out:
– Specific Fitment: compatible with Harley-Davidson Dyna and Softail models.
– Perfect Fit: ideal for replacement wires, relocation kits, and custom aesthetic changes.
– High-Quality Material: wear-resistant, high reliability, and durable for long-term use.
– Function: timely replacement prolongs engine service life and reduces fuel waste.
– Package Content: clearly specifies 2 red spark plug wires (8″ and 20″ pre-crimped).

Pros:
– Durable and reliable construction for long-term performance.
– Specific pre-crimped lengths (8″ and 20″) are convenient for Harley installations.
– Contributes to better engine health and efficiency.
– Good for both standard maintenance and custom modifications.

Cons:
– This is a spark plug wire kit, not the spark plugs themselves, meaning it won’t impact spark quality directly.

Best for: Harley Dyna and Softail owners looking for a visually appealing (red) and functionally sound replacement for their spark plug wires, with clear sizing.

Expert Opinion: Tavaski’s wire kit provides a solid, durable option for Harley owners. The clear sizing and direct fitment make it an easy choice for anyone looking to refresh their ignition system’s wiring, contributing to overall engine reliability.

Helpful Comparison Insights

Navigating the world of Harley Davidson ignition components can feel a bit overwhelming, especially when some products are actual Harley Davidson spark plugs and others are essential wires. Let’s break down how these options stack up to help you make an informed decision.

For riders primarily focused on spark plug performance and engine efficiency, the NGK Iridium IX DCPR7EIX (both the original and the #6046/97637 listings) and the CNPAPC Double Iridium IX plugs are your top contenders. The NGK plugs are a globally trusted name, often an OEM choice, delivering reliable, high-performance sparks and excellent longevity thanks to their iridium construction. They’re a solid, no-brainer upgrade. The CNPAPC Double Iridium plugs, while from a lesser-known brand, promise even greater durability and extreme ignitability with their double iridium alloy, potentially offering a more aggressive performance boost and improved fuel economy for riders who want to maximize their Harley’s potential. If you’re looking for an alternative design that focuses on combustion efficiency and reduced emissions, the E3 Spark Plugs E3.36 stand out with their unique DiamondFIRE technology. They promise measurable gains in power and fuel economy by ensuring a more complete burn, making them a great choice for eco-conscious riders or those seeking a cleaner-running engine.

Now, for the spark plug wires, which are just as critical for delivering that spark to your Harley Davidson spark plugs. All three wire kits reviewed—Motoforti, the Generic 2 Pcs 10.4mm 10mm kit, and Tavaski—are designed as direct replacements for specific Harley Dyna and Softail models (replacing DYNA-409RD). They all feature high-temperature silicone construction, which is vital for durability and consistent performance in a hot engine environment. The Motoforti kit and the Generic kit are very similar in features, offering robust, pre-crimped wires that are excellent for maintenance or custom looks. The Tavaski kit provides similar benefits but stands out by clearly detailing the two specific wire lengths (8″ and 20″) and coming in a distinct red color, which might appeal to those looking for a visual upgrade. Choosing between these wire kits often comes down to brand preference, specific included lengths, or even color, as their core functions and quality seem quite comparable.

Ultimately, your best choice depends on whether you’re prioritizing a spark plug upgrade for raw performance or efficiency, or if you need to replace your spark plug wires for better reliability and a refreshed ignition system. Many riders find that upgrading both simultaneously offers the most noticeable improvement in their Harley’s overall ride quality.

Final Verdict

Deciding on the “best” components for your beloved Harley always comes down to your riding style, priorities, and budget.

If ultimate performance and long-term reliability from your actual spark plugs are your main goals, you can’t go wrong with the NGK Iridium IX DCPR7EIX. They are a proven, OEM-trusted choice that consistently deliver.

For riders chasing an extra edge in power, fuel efficiency, and cutting-edge durability at a competitive price, the CNPAPC Upgrade Double Iridium IX Spark Plugs are a very strong contender. Their double iridium design offers significant advantages.

If your focus is on cleaner combustion, reduced emissions, and measurable gains in efficiency and horsepower through innovative design, the E3 Spark Plugs E3.36 Premium Powersports Spark Plug offers a unique and effective solution.

And let’s not forget about the unsung heroes of the ignition system: the wires. For replacing your spark plug wires, all three kits—Motoforti, the Generic 2 Pcs 10.4mm 10mm Motorcycle Spark Plug Wire Kit, and Tavaski—offer excellent, high-temperature silicone options specifically for Harley Dyna and Softail models. Your choice here might hinge on visual preference, specific lengths, or brand familiarity, but any of them will provide a solid, reliable connection for your Harley Davidson spark plugs.

Ultimately, a healthy ignition system requires both top-notch spark plugs and robust wires. Consider what your Harley needs most, and choose with confidence!

Comprehensive FAQ Section

1. How often should I change my Harley Davidson spark plugs?
Generally, it’s recommended to inspect your Harley Davidson spark plugs at every major service interval (e.g., 5,000 to 10,000 miles) and replace them every 15,000 to 30,000 miles. However, this can vary based on your riding style, engine condition, and the type of spark plug. Iridium or double iridium plugs often have a longer lifespan than standard copper plugs.

2. What’s the difference between iridium, platinum, and standard copper spark plugs for Harleys?
* Copper plugs are the most basic and conductive, but wear out faster. They’re good for older engines or those that run hot.
* Platinum plugs offer better durability and last longer than copper, with a finer electrode for a more consistent spark.
* Iridium (and Double Iridium) plugs are the most advanced, featuring an extremely fine and durable electrode made from one of the hardest metals. They provide the most focused, powerful, and consistent spark, leading to improved ignitability, throttle response, and significantly longer lifespan. For Harley Davidson spark plugs, iridium is often the go-to for performance upgrades.

3. Are pre-gapped spark plugs okay for my Harley?
Yes, most modern Harley Davidson spark plugs, especially iridium types, come pre-gapped to the manufacturer’s recommended specifications. While it’s always good practice to double-check the gap with a wire gauge, avoid trying to adjust iridium tips as they are very fragile and can be easily damaged. For other types, slight adjustments might be needed based on your Harley’s exact model and engine tuning.

4. Can spark plug wires impact my Harley’s performance?
Absolutely! Spark plug wires are crucial for delivering the high voltage from your ignition coil to the Harley Davidson spark plugs. Old, cracked, or degraded wires can lead to resistance, misfires, reduced power, poor fuel economy, and even stalling. Upgrading to high-quality, high-temperature resistant silicone wires ensures consistent spark delivery and can significantly improve engine reliability and efficiency.

5. How do I choose the right heat range for my Harley Davidson spark plugs?
The heat range refers to a spark plug’s ability to dissipate heat from the combustion chamber. A “hot” plug stays hotter to burn off deposits, while a “cold” plug dissipates heat faster to prevent overheating. For most stock or mildly modified Harleys, sticking to the manufacturer’s recommended heat range (e.g., the DCPR7EIX code indicates heat range) is best. Heavily modified or high-performance engines might benefit from a slightly colder plug to prevent pre-ignition. Always consult your service manual or a professional tuner.

6. Will upgrading my spark plugs improve my Harley’s fuel economy?
Yes, in many cases, upgrading to higher-quality Harley Davidson spark plugs like iridium or double iridium can lead to improved fuel economy. Their ability to deliver a more efficient and complete burn means less wasted fuel and more power extracted from each combustion cycle. While results vary, a smoother, more efficient engine generally translates to better miles per gallon.

7. What does “DCPR7EIX” mean in Harley spark plug codes?
NGK’s spark plug coding system provides a lot of information:
* D: Thread diameter (12mm)
* C: Thread reach (19mm)
* P: Projected insulator type
* R: Resistor type (suppresses electrical noise)
* 7: Heat range (lower number = hotter plug, higher number = colder plug; 7 is a common mid-range for Harleys)
* E: Thread length (19mm)
* IX: Iridium IX type (designates the Iridium material and fine wire electrode)
Understanding these codes helps ensure you’re getting the correct spark plugs for Harley Davidson motorcycles that match your engine’s requirements.