5 Best Spark Plugs for Harley Davidson Twin Cam Engines

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Mr. Chase Manhattan

When it comes to optimizing your Harley Davidson Twin Cam engine, selecting the right spark plugs is vital. The spark plugs mentioned in this list have been carefully selected to enhance both performance and efficiency. Each spark plug offers unique benefits that can elevate your riding experience. From increased horsepower gains to improved throttle response, these top 5 spark plugs are designed to bring out the best in your Harley Davidson Twin Cam engine. So, if you're looking to take your ride to the next level, exploring these spark plug options might just be the solution to revealing your bike's full potential.

Things to Note

  • Choose spark plugs compatible with your Twin Cam model for optimized performance.
  • Prioritize durability with platinum or iridium-tipped plugs for longevity.
  • Fuel efficiency improves with high-quality spark plugs promoting complete combustion.
  • Look for warranties covering defects to ensure quality and reliability.
  • Tailoring spark plugs enhances engine performance, horsepower, and fuel efficiency.

NGK Iridium IX DCPR7EIX Spark Plugs for Harley Davidson Twin Cam

ngk iridium spark plugs

For Harley Davidson Twin Cam owners seeking enhanced performance and easy installation, the NGK Iridium IX DCPR7EIX Spark Plugs are the ideal choice.

These spark plugs, designed for 1999-2016 Harley Davidson Twin Cam models, offer a significant boost of up to 3HP. The iridium electrode, 25% smaller than platinum, reduces the voltage requirement while the ultra-small diameter center electrode extends the ignition system's life.

Additionally, the new metal shell plating enhances anti-corrosion qualities, ensuring durability in various riding conditions. Customers have praised these spark plugs for their smooth starting and running capabilities, highlighting their compatibility across different Harley Davidson models.

With positive feedback on both ease of installation and performance improvement, the NGK Iridium IX DCPR7EIX Spark Plugs prove to be a reliable choice for Twin Cam enthusiasts.

Best For: Harley Davidson Twin Cam owners looking to boost performance and improve ignition system efficiency.


  • Up to 3HP gain for enhanced performance
  • Iridium electrode reduces voltage requirement
  • Ultra-small diameter center electrode extends ignition system life


  • Higher initial cost compared to standard spark plugs
  • May not fit all Harley Davidson models outside the specified range
  • Limited compatibility with non-Twin Cam engines

Accel 2418 Spark Plugs (Pair) 6R12 for Harley Davidson Twin Cam

accel 2418 spark plugs

Ideal for enhancing the performance of Harley Davidson Twin Cam engines, the Accel 2418 Spark Plugs (Pair) 6R12 offer a reliable and efficient spark plug option. Manufactured by ACCEL, these spark plugs come with a metallic finish exterior, weighing only 0.01 ounces.

The product dimensions are 4.6 x 2 x 1.2 inches, and the item model number is Accel-2418 with a manufacturer part number of 2418 and OEM part number of 6R12. With a Best Sellers Rank of #3,465 in Automotive Replacement Spark Plugs, the Accel 2418 spark plugs have garnered positive feedback with a 4.3 out of 5 stars rating based on 94 customer reviews.

Users praise their performance and compatibility with Harley Davidson Twin Cam engines, making them a popular choice for those seeking improved efficiency and power.

Best For: Motorcycle enthusiasts looking to enhance the performance of their Harley Davidson Twin Cam engines with reliable and efficient spark plugs.


  • Positive feedback from users on performance and fit for Harley Davidson Twin Cam engines.
  • Metallic finish exterior adds a stylish touch to the spark plugs.
  • Lightweight design at only 0.01 ounces makes handling and installation easier.


  • May not be compatible with all motorcycle models, limiting versatility.
  • Limited warranty and support options compared to some other spark plug brands.
  • Pricing may be higher compared to other spark plug options on the market.

NGK Spark Plugs 6046 Iridium IX Spark Plug for Harley-Davidson Twin Cam and XL

high performance spark plug model

With its advanced design and performance benefits, the NGK Spark Plug 6046 is recommended for Harley-Davidson Twin Cam and XL engines that demand superior ignition efficiency.

This spark plug, part number DCPR7EIX (6046), features NGK's IRIDIUM IX technology, providing improved throttle response, better fuel efficiency, and overall enhanced engine performance.

Customers have praised its ability to make bikes run smoother, with cleaner combustion compared to conventional spark plugs. The NGK Spark Plug 6046 has garnered positive feedback, with users reporting extended durability and reliability.

With a solid customer rating and a reputation for longevity, this spark plug is a popular choice among motorcycle enthusiasts looking to optimize their Twin Cam and XL engines for peak performance.

Best For: Riders of Harley-Davidson Twin Cam and XL engines seeking superior ignition efficiency and enhanced engine performance.


  • Improved throttle response
  • Better fuel efficiency
  • Cleaner combustion compared to conventional spark plugs


  • Higher initial cost compared to standard spark plugs
  • Specific compatibility with Harley-Davidson Twin Cam and XL engines only
  • May not provide significant performance gains for all riders

Accel Platinum Spark Plugs for Buell HD Big Twin Cam 86-10

high performance spark plugs description

Platinum-tipped for extended longevity and enhanced durability, the Accel Platinum Spark Plugs suit riders seeking superior performance in their Buell HD Big Twin Cam 86-10 motorcycles.

Crafted from state-of-the-art components, these spark plugs feature a platinum tip for extended lifespan and a knurled chromium-nickel alloy side wire that enhances spark delivery.

The pure copper core design helps reduce particulate buildup, ensuring consistent performance.

Sold in pairs and made in the USA, these spark plugs come with a .040in. gap and bear the Spark Plug Code Y2418P.

With positive customer reviews praising their quality and performance, these Accel Platinum Spark Plugs are a popular choice among riders looking to optimize their Buell HD Big Twin Cam 86-10 engines.

Best For: Riders of Buell HD Big Twin Cam 86-10 motorcycles seeking enhanced performance and durability in their spark plugs.


  • Platinum-tipped for extended longevity
  • Knurled chromium-nickel alloy side wire for enhanced spark delivery
  • Made in the USA with state-of-the-art components


  • Mixed feedback on the color of the plugs
  • Compatibility with specific motorcycle models may vary
  • Some users reported plugs made in Japan, not the USA

CNPAPC Upgrade Double Iridium IX Spark Plugs for Harley Davidson Twin Cam

high performance spark plugs

Boasting extreme flammability and enhanced throttle response, the CNPAPC Upgrade Double Iridium IX Spark Plugs cater to performance enthusiasts seeking peak spark plug performance for their Harley Davidson Twin Cam engines.

These spark plugs are designed with double iridium material to optimize the best performance, with a rare occurrence of the flameout phenomenon. Users can expect lower fuel consumption, high durability, and a stable spark for prime engine efficiency.

The trivalent metal plating further enhances acceleration and durability, making them a reliable choice for various Harley Davidson models. With compatibility across different models and a reputation for being used by professional car drivers, these spark plugs come in a pack of two with a 12-month warranty, prioritizing customer satisfaction and quick issue resolution.

Best For: Performance enthusiasts and professional car drivers looking to optimize the performance of their Harley Davidson Twin Cam engines with extreme ignitability and improved throttle response.


  • Extreme ignitability and enhanced throttle response for peak performance
  • Rare occurrence of flameout phenomenon ensuring engine reliability
  • Trivalent Metal Plating for outstanding acceleration and durability


  • Some issues with thread pitch compatibility reported
  • Recommendations for gap adjustment may be needed
  • Specific model compatibility issues may arise

Factors to Consider When Choosing Spark Plugs for Harley Davidson Twin Cam

When choosing spark plugs for your Harley Davidson Twin Cam, consider factors like:

  • Plug material quality
  • Performance enhancement
  • Compatibility check
  • Durability
  • Lifespan
  • Fuel efficiency benefits

Ensuring the right material quality can impact performance, while compatibility and durability are essential for long-term use.

Keep in mind that selecting the right spark plugs can't only enhance your bike's performance but also improve fuel efficiency.

Plug Material Quality

Consideration of the plug material quality is vital when selecting spark plugs for your Harley Davidson Twin Cam engine. The quality of the plug material, such as iridium or platinum, plays a pivotal role in determining the spark plug's performance and longevity.

High-quality materials like iridium or platinum offer superior conductivity, heat resistance, and durability compared to traditional options. Platinum-tipped spark plugs, in particular, are favored for their extended service life and enhanced resistance to wear and corrosion, making them an excellent choice for high-performance applications.

On the other hand, iridium spark plugs are renowned for their fine wire electrode, which demands less voltage to spark and delivers a consistent and stable spark over time. Opting for spark plugs crafted from premium-quality materials can result in notable improvements in engine performance, fuel efficiency, and overall reliability for your Harley Davidson Twin Cam.

Performance Enhancement

To enhance the performance of your Harley Davidson Twin Cam engine, it's important to take into account specific factors when selecting spark plugs. Upgrading your spark plugs can greatly boost your engine's performance by enhancing ignition efficiency and combustion.

By opting for high-quality spark plugs, you can experience benefits such as increased horsepower, improved fuel efficiency, and smoother acceleration. The design and materials of the spark plugs play a pivotal role in enhancing throttle response and overall engine operation.

Ensuring that your spark plugs are properly gapped is crucial as it contributes to consistent ignition timing and helps in reducing emissions. Remember, choosing spark plugs that are specifically tailored to your Harley Davidson Twin Cam model can maximize its performance potential, ensuring you get the most out of your ride.

Compatibility Check

Make sure that you choose spark plugs compatible with your specific Harley Davidson Twin Cam model and year to optimize performance. To guarantee compatibility, check the manufacturer's recommendations or refer to your motorcycle's manual for the recommended spark plug types.

Factors such as thread pitch, heat range, electrode material, and gap size play critical roles in determining compatibility. Using spark plugs that aren't suitable for your Twin Cam can result in poor ignition, engine misfires, and even potential damage to your motorcycle's engine.

If you're uncertain about which spark plugs are compatible with your Harley Davidson Twin Cam, it's advisable to consult with a mechanic or an expert in the field. By selecting the right spark plugs tailored to your bike's specifications, you can enhance performance, improve efficiency, and prolong the lifespan of your Twin Cam engine.

Durability and Lifespan

When selecting spark plugs for your Harley Davidson Twin Cam, prioritize durability and lifespan to guarantee peak performance and longevity of your engine. Spark plugs with platinum or iridium tips offer a longer lifespan compared to traditional copper spark plugs.

Factors such as electrode material, insulation, and construction can influence the longevity of spark plugs. High-quality spark plugs can last anywhere from 30,000 to 100,000 miles, depending on driving conditions and maintenance practices.

Regular maintenance, including proper gap adjustments, can help extend the lifespan of spark plugs for Harley Davidson Twin Cam engines. Additionally, choosing spark plugs with superior anti-corrosion properties can aid in maintaining endurance in various environmental conditions.

Fuel Efficiency Benefits

Consider the fuel efficiency benefits of choosing the right spark plugs for your Harley Davidson Twin Cam, as they play an essential role in optimizing combustion and saving on fuel costs over time.

Upgrading to high-quality spark plugs can improve fuel efficiency by ensuring complete combustion of the air-fuel mixture. Efficient spark plugs promote better ignition, reducing unburned fuel that can lead to wasted energy and decreased mileage. Enhanced spark plug technology, like iridium or platinum, can provide a more consistent spark, optimizing fuel consumption.

Properly gapped spark plugs contribute to efficient combustion, maximizing power output while minimizing fuel usage. By investing in spark plugs designed for performance, you can help your Harley Davidson Twin Cam motorcycle run more efficiently, ultimately saving you money on fuel costs in the long run.

Making the right choice in spark plugs can lead to significant improvements in fuel efficiency, benefiting both your wallet and the environment.

Warranty Coverage

For peace of mind when selecting spark plugs for your Harley Davidson Twin Cam, factor in the length and scope of the warranty offered by the manufacturer. It's important to look for warranties that cover defects in materials or workmanship to guarantee quality assurance.

Some warranties may have specific duration or mileage limits, so be sure to check the terms carefully. A warranty can provide protection against premature wear or failure of the spark plugs, saving you from unexpected expenses.

By understanding the warranty coverage, you can make an informed decision on which spark plugs to choose for your Harley Davidson Twin Cam. Remember, a strong warranty reflects the manufacturer's confidence in their product and can indicate reliability.

Prioritize warranties that offer extensive coverage and align with your usage needs to maximize the benefits of your spark plug investment.

Frequently Asked Questions

Can I Use These Spark Plugs for Other Motorcycle Brands?

Yes, you can use these spark plugs for other motorcycle brands as long as they're compatible with the engine specifications of your specific motorcycle model.

It's crucial to check the manufacturer's recommendations and make sure that the spark plugs meet the necessary heat range and size for the best performance.

Using the correct spark plugs can assist in improving your motorcycle's efficiency and overall performance.

Do These Spark Plugs Require Any Special Tools for Installation?

When installing these spark plugs, no special tools are needed. Just make sure you have a socket wrench and spark plug socket on hand.

Remember, 'measure twice, cut once' to avoid any errors during installation.

With the right tools and a steady hand, you'll have those spark plugs in place in no time.

Just follow the manufacturer's guidelines for torque specifications to achieve peak performance.

Will Upgrading Spark Plugs Void My Harley Davidson Warranty?

Upgrading your spark plugs may void your Harley Davidson warranty. Checking your warranty terms before making any modifications is crucial to avoid potential issues in the future.

If you're unsure about the impact on your warranty, seek advice from your dealership or a certified technician. It's wiser to err on the side of caution when it comes to safeguarding your warranty coverage.

How Often Should I Replace Spark Plugs in My Twin Cam Engine?

You should replace spark plugs in your twin cam engine every 10,000 to 20,000 miles. Regular replacement helps maintain peak performance and fuel efficiency. It's a simple maintenance task that ensures your engine runs smoothly.

Keep an eye out for signs of wear or poor performance, like misfires or rough idling, which may indicate it's time for a change. Regular upkeep keeps your ride running strong.

Are There Any Specific Maintenance Tips for These Spark Plugs?

When it comes to maintenance tips for spark plugs in your Twin Cam engine, it's important to regularly check for signs of wear or damage.

Make sure to clean the spark plugs and inspect them for any buildup or corrosion. Also, verify they're properly gapped and torqued to specifications.

Regularly replacing spark plugs at recommended intervals will help keep your engine running smoothly and efficiently.


As you ride with the top spark plugs for your Harley Davidson Twin Cam engine, remember that they're more than just components – they're the spark that ignites your passion for the open road.

Choose wisely and feel the power beneath you, propelling you forward with each twist of the throttle.

Embrace the journey ahead with confidence, knowing that your Harley Davidson is equipped with the best spark plugs to boost performance and efficiency.

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Hey y’all! It’s Chase Manhattan, a life-long gearhead, tinkerer, and adrenaline junky. I like to write about all things technical in the Harley Davidson and motorcycling space.