5 Best Spark Plugs For Harley Davidson

The efficient ignition system of a motorcycle is made possible by a key component called a spark plug. Having a high-quality plug is surely beneficial to your motorcycle. And especially in the case of Harley- Davidson, you have to be tactful in choosing. You know, a spark plug ensures that you can start your motorcycle and accelerate fast and efficiently.

So, it’s easy to ignore and assume the hesitation, but in reality, it could halt your journey. In this review, we’ll expound on the Best Spark Plugs for Harley Davidson. Also, there is a recommendation of what every rider who values efficiency should purchase.

Read More: How to Change Spark Plugs on a Harley?

Types of Motorcycle Spark Plugs

There are mainly three types of spark plugs. Many experts also emphasize four types. However, all the information will be in the middle of our three types of discussions.

Copper Spark Plug

For a long time, motorcycle riders have been using copper spark plugs. These plugs commonly fit in motorcycles because they are affordable and available. However, the plugs have lately faced replacement as the newer engine version can’t run on them. These sparks use copper metal. However, copper spark plugs’ lifespan is 10,000 to 20,000 miles.

Platinum Spark Plug

Platinum plugs are relatively more expensive than copper plugs. But operates at a lower temperature. They are of two types; single or double-plated. Double-plated platinum spark plugs are expensive but offer more efficiency and performance. Additionally, platinum spark plugs life last longer than copper plugs. It can last up to 60,000 miles.

Iridium Spark Plug

These spark plugs are the most reputable but are a bit expensive.  They offer optimized gas mileage, performance, and reliability. An iridium spark plug can be of two types; single or double-plated iridium plug. Double-plated iridium plugs are more expensive than single-plated ones. Do you know iridium spark plugs live? Standard iridium plugs last up to 80,000 miles.

Product Reviews: 5 Best Spark Plugs for a Harley Davidson

There are dozens of spark plugs that fit a Harley Davidson. However, very few work efficiently and last longer. The below-listed plugs are specially hand-picked.

1. E3 Spark Plugs- Best Spark Plugs for a Harley Davidson


It is a product of the E3 spark plug brand, and it promises to deliver optimal performance. The plugs increase power and improve fuel efficiency in your motorcycle. The features of this product are as follows.

  • The design of the plug is ideal for use in cold temperatures.
  • The plug contains Yttrium alloy that enhances up to 8% inside wire temperatures.
  • It is durable and has a less pre-ignition effect.
  • The product has a thread diameter of 12mm for universal fit.
  • It helps you save more on fuel hence fewer costs.
  • The product is cheap compared to other plugs.
  • It delivers quick starts and smooth acceleration.
  • It features a copper electrode for enhanced heat transfer.
  • The plug has a multi-rib insulator to reduce misfires
  • It has a high nickel alloy for extended life and durability.
  • It has a five years warranty hence improving customer experience.

2. NGK- Best Ngk Iridium Spark Plugs for Harley Davidson


NGK is amongst the top brands reputable in manufacturing spark plugs. This specific iridium plug is for use in a motorcycle, and its core material is nickel. NGK claims that the product represents a mixture of performance and innovation.

  • The product uses advanced technology to ensure high efficiency.
  • The plug has a high customer rating on efficiency.
  • It fires instantly and accelerates smoothly.
  • They work perfectly with Harley Davidson bikes like the Softail.
  • It helps save on fuel economy.
  • Most experts highly recommend these plugs.
  • The plug may be hard to install.

3. Champion Store- Best Spark Plugs for Harley Davidson Evo


The product’s manufacturing brand is champion and promises dependable performance. The manufacturing company praises its durability and efficiency.

  • The plug offers dependable performance and durability
  • It features a copper core for improved thermal conductivity.
  • The copper core controls heat production for longer plug life.
  • The product resists corrosion by using highly durable materials.
  • It has a high customer rating on ease of installation.
  • The plug works perfectly in most Harley Davidson, including EVO road King.
  • It is a reputable fuel economy spark plug.

4. Cycle Parts- High-performance Spark Plugs for Harley Davidson


Orange cycle parts is an online store that claims fun in making motorcycle parts. Some of the parts the company claims to offer are exhausts, tires, and spark plugs. The company claims that this product uses ceramic materials and can fit the 1999-2017 Harley Electra Glide classic.

  • This spark plug has high heat transfer to avoid damage.
  • The ceramic material gives the plug a unique look.
  • It has a nearly pure insulator to prevent heat loss.
  • You can set the gap to ensure it works perfectly.
  • The spark plug is easy to install and takes less than 10 mins.
  • They are long-lasting without much need for attention.
  • The product has vibrant sparks and starts effortlessly.
  • May build up a carbon layer that decreases efficiency.

5. NGK- NGK Spark Plugs for Harley Davidson


NGK is one of the most reputable spark plug-making companies. Customers highly value iridium spark plugs for their improved efficiency and durability. The core of this plug is fitted with nickel metal to enhance its performance.

  • The plugs come pre-gapped to improve the firing cycle.
  • It has a small size nickel electrode to reduce voltage requirements.
  • The plug has a metal shell plating that acts as the anti-corrosion agent.
  • The iridium electrode is 25% smaller to extend the life of the ignition system.
  • Customers rate the product highly due to its efficiency.
  • These plugs fit in most Harley bikes, including EVO road King.
  • The product comes in pairs for the price.

Editorial Recommendation:

We recommend every rider should aim to have a double-iridium spark plug. These qualities plug translate to excellent performance, power, efficiency, and reliability on your bike. The list below is of high-quality plugs from reputable brands that you can select from.

More: Many have emailed us about the best spark plug sockets. We intend to discuss spark plug sockets in the future. However, we are currently recommending this LEXIVON 5/8″ Swivel Magnetic Spark Plug Socket [Amazon] from our usage experience.

Buying Consideration for Best Spark Plugs for a Harley Davidson

There is what you should consider before buying the best spark plug. Below is a highlight of these factors.


Consider buying a spark plug that’s within your budget. The price ranges between $3 and $10 depending on the type and the manufacturing brand. As fore mentioned, an Iridium spark plug is expensive compared to platinum and copper spark plugs. 


There are three materials used in making spark plugs. The three materials include copper, iridium, and platinum. Copper spark plugs are a little old-school and work best in older engine versions. Motorcycles using modern engines work best with platinum and iridium spark plugs. The two offer optimum performance and are durable.


A spark plug can either be hot or cold depending on how well or badly it conducts heat. Hot spark plugs are poor conductors and better insulators of heat. Therefore, they retain a lot of heat at the igniting tip. Cold spark plugs are poor insulators and better conductors of heat. So, they transmit heat fast from the tip. The range is denoted using numbers on the spark plug.


Different bikes require spark plugs of varying sizes. The common spark plug sizes are10mm, 12mm, and 14mm. The higher the size the higher the price of the spark plug.

Who Makes Harley Davidson Spark Plugs?

Many reputable companies make spark plugs for Harley Davidson. This article has selected products from top brands like E3 Spark Plugs, NGK, Champion Store, and Cycle Parts. In fact, we have taken the best 5 spark plugs for Harley from our experience of use. However, here we are about some other renowned brands who have reputations over the bikers.


The brand was founded in 1886 by Robert Bosch as a workshop for mechanics and electrical engineering. The company claims to be a leader in mobility solutions, consumer goods, industrial technology, energy, and building technology. The company’s headquarters are in Stuttgart, Germany. The brand is the proud producer of the Bosch FR7NPP332 Double Platinum Spark Plug(Amazon).


This brand is a part brand launched in 1972 by the ford company as its official parts brand.  The brand works, designs, and manufactures spark plugs and air conditioning products. It also designs and produces brakes, batteries, and other starting and charging products. Motorcraft Platinum sparkplug(Amazon) is a product of this Motorcraft brand.


The brand claims to have been producing aftermarket parts for over 100 years since 1908. The brand specializes in the production of batteries, filters, and spark plugs among many others.  This brand is mainly known for the production of ACDelco 41-993 spark plugs(Amazon).

How Spark Plug Working

A spark plug remains in the cylinder head and generates an electric spark. However, if you look at the modern ignition system, you will see the relation between battery, coil, spark plug, switch, and pick-up coils. Well, we think the video below will enable you to easily understand how a spark plug works.

Read Also: How spark plugs work.

Frequently Asked Questions

Q. When to change motorcycle spark plugs?

15,000-16,000 miles. Additionally, the experts recommend regular inspections and, if necessary, replacement. Some possibilities that should trigger replacement include sputtering and loss of power.

Q. How long does it take to change a spark plug?

30-60 minutes. However, the changing time depends on factors like the type of engine and your experience. Mechanics will surely take less time compared to novices.

Q. How much does it cost to replace spark plugs?

$20-$50. Spark plugs cost between $3 and $10, while the labor could range from $10 to $100. The cost depends on your purchase point and who does the replacement.

Q. Are NGK Spark Plugs good for Harley Davidson?

Yes. Most experts recommend riders purchase the NGK Iridium IX Spark Plug, one of the brand’s products. They are recommended as they work efficiently and are durable.

Q. How do I know my spark plugs are faulty?

When the motorcycle spark plugs are faulty, the motorcycle will misfire, backfire and have a flooded engine. Also, you can inspect for physical signs on the plugs like rust and corrosion.

Final Words

The ignition system plays a major role in your motorcycle that cannot be ignored. Some of the roles it plays in ensuring consistent optimal combustion of gases in the engine, it’s better fuel economy, and smooth and reliable starts. If your Harley Davidson isn’t doing this, it is likely spoilt. Having the best spark plug for your Harley Davidson is the prayer of every motorcycle rider.

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