Reviews

Best Motorcycle Spark Plugs: Change Your Spark Plugs Anywhere

Changing your own spark plugs is a great way to save money.

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BY Daniel Rika , Jason Collins , Linsay Thomas / LAST UPDATED ON April 7, 2021

You may have to replace the spark plugs on your motorcycle if it starts to sputter, lose power, or simply isn't running well. You can also check your owner's manual to see how often they need to be replaced. Another way to check if you need new plugs is to remove them and see if the gap is correct and if the electrode is burned away. If you know it's time to replace your motorcycle spark plugs, there are various options available. Check out some of the best in our buying guide below.

Best Overall
NGK Iridium IX Spark Plugs
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Summary
Summary

These NGK iridium spark plugs come in a pack of two and a gap of .025 out of the box which can be further set and adjusted. Works great on Harley-Davidson motorcycles.

Pros
Pros
  • Bodies of these spark plugs are made from iridium, making ignition much faster and effective in comparison to spark plugs with copper bodies
  • Solid iridium core holds gases in place and allows for a more responsive engine
Cons
Cons
  • These spark plugs have high reactivity and fuel up too easily for carbureted bikes
Best Overall
NGK Iridium IX Spark Plugs
Best Value
E3 Spark Plug Powersports
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Summary
Summary

These E3 spark plugs are widely popular among motorcyclists and are a step up from the standard spark plug. They come in a variety of sizes.

Pros
Pros
  • Features a DiamondFIRE ground electrode configuration for faster ignition
  • Nickel-plated to last longer and protect against corrosion
Cons
Cons
  • This plug does not work well on motorcycles with large gaps. This spark plug works best with Harley-Davidson motorcycles.
Best Value
E3 Spark Plug Powersports
Honorable Mention
Denso Platinum TT Spark Plug
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Summary
Summary

These Denso Platinum spark plugs feature a twin-tipped design, a platinum center electrode, and a titanium-enhanced alloy surrounding the ground electrode.

Pros
Pros
  • These spark plugs come pre-gapped and are double tipped
  • Paired with the precious metals surrounding the core, these plugs are meant to last more than 60,000 miles
Cons
Cons
  • Depending on the bike, the material of these plugs may not be suitable for every type of motorcycle model
Honorable Mention
Denso Platinum TT Spark Plug

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Why Buy a Motorcycle Spark Plug?

  • Improve your starting power. Without a healthy spark plug, your bike won’t achieve maximum starting power or may fail to start entirely. That’s because the gap of the spark plug may be too large and may not be able to spark electricity to ignite your motorcycle’s combustion system.
  • Improve engine performance. A spark plug produces a sufficient amount of spark to burn the air-fuel mixture in the combustion system. Using a new and correctly gapped spark plug ensures that you prevent early ignitions or skipped firing, which can damage the engine. 
  • Replace your burnt spark plug. A burnt spark plug will have slight discoloration at the negative probe. If you measure the gap between the ground electrode and center electrode, you may notice that it’s a bit wider. If you don’t replace it, the probe will burn away and cause the engine to misfire. 
  • Keep the engine cool. A spark plug helps to transfer excess heat from the cylinder ignition chamber to the engine’s cooling system. If you have a healthy one, you won’t have to stop frequently during long trips to cool your engine.  
  • Improve fuel economy. A healthy spark plug helps your vehicle to maintain sufficient starting power, which in turn saves the amount of fuel the engine burns. Spark plugs also burn off contaminants and other deposits from fuel additives. That translates to fewer fuel emissions from your motorbike. 

Types of Motorcycle Spark Plugs

Copper 

Copper-tipped spark plugs are the most common and standard form of the spark plug. Copper is one of the best conductors of electricity, and for that reason, copper plugs do not overheat easily. That extends the life of the spark plug. They are typically inexpensive and can last for several thousand miles before they start to erode naturally. 

Single Platinum 

Single platinum plugs are more expensive than copper despite the fact that they are less conductive than the latter. That’s because they tend to last longer since the metal does not erode or wear out as easily as copper. Platinum-tipped spark plugs can last much longer than copper plugs, but may experience slight overheating issues.  

Double Platinum 

Double platinum spark plugs have double plates of platinum on the tip. They can, therefore, last longer and perform better than the single-platinum versions. They are also more expensive. However, they still experience overheating issues since the properties of platinum remain the same. 

Iridium 

Iridium isn’t a great conductor of electricity, but that doesn’t compromise on its performance as a spark plug. In fact, iridium plugs can outlast the copper versions; they have a service life of about 40,000 to 80,000 miles, depending on the manufacturer. However, they are the most expensive of the four versions, since iridium is a harder metal to find. 

Top Brands

Denso 

Denso is a Japanese brand that’s been a leading supplier of automotive components since its inception in 1972. Denso products feature cutting-edge technology, and that’s why they come as OEM equipment on most General Motors, Honda, Toyota, Ford, Mercedes Benz, and Volvo equipment. Some of its best spark plugs for motorcycles are the Denso Platinum TT Spark Plug and the Denso Iridium Long Life Spark Plugs.

NGK 

NGK is a Japan-based company that has more than 80 years of experience in making OEM and aftermarket accessories for the automotive and aviation industries. Some of its products include spark plugs, glow plugs, oxygen sensors, and ignition coils. If you want to try out a few NGK spark plugs, you can check out the NGK Iridium IX Spark Plugs and NGK G-Power Spark Plug.

E3 Spark Plugs 

E3 Spark Plugs designs environmentally friendly spark plugs that offer a complete and cleaner fuel burn. It makes spark plugs for trucks, race cars, snowmobiles, ATVs, lawnmowers, and motorcycles. Some of the best spark plugs in its repertoire are the E3 Spark Plug Powersports and E3 Spark Plug Automotive

ACDelco 

ACDelco is a renowned manufacturer of automotive parts that’s a subsidiary company of General Motors. The company was founded in 1916 and is currently headquartered in Grand Blanc, Mich. If you would like to try out a high-quality, performance spark plug from the company, check out the ACDelco Professional Iridium Spark Plug

ACCEL

Based in Cleveland, Ohio, ACCEL has been making spark plugs, tune-up kits, fuel injectors, and more for over 40 years. They're a popular brand on the race track, drag strip, and among hot rodders. We like the Accel U-Groove Spark Plugs For Harley Big Twin / Sportster.

Pulstar

According to Pulstar, its spark plugs generate a spark that releases 20,000 times more power than regular spark plugs. Based in Albuquerque, New Mexico, Pulstar founder Lou Camilli worked with Sandia National Laboratories to make a product that would increase combustion efficiency. We recommend checking out the Pulstar Spark Plug.

Motorcycle Spark Plug Pricing

  • Under $20: Expect to find either copper- or nickel-tipped spark plugs within this price range. You can get a high-quality spark plug from a well-known brand that comes pre-gapped and has good corrosion resistance. Most can also resist pre-ignition. 
  • $20-$90: This price range consists of platinum, iridium, and heavy-duty copper spark plugs. Most also come pre-gapped and are well designed to resist electrode burnouts from excess heat combustion. You are less likely to experience engine misfires with a spark plug that’s higher on the price scale. 

Key Features 

Gapping 

If you don’t know how to correctly gap a spark plug, prioritize spark plugs that come pre-gapped. The gap is the space between the tip (center electrode) and the curve (ground electrode). Correct gapping helps to prevent engine misfires and increase your bike’s fuel efficiency. 

Ground Electrode Type  

A spark plug can have two or more ground electrodes surrounding the central electrode. The ground electrode is the probe-like structure that protrudes from the threads. The most common type is a single and double electrode. More electrodes means that you can extend the life of the spark plug since you can rely on the second ground electrode when one burns out. However, it compromises the fuel efficiency of your vehicle. 

Threads 

The number of threads on the spark plug determines its level of reach into the combustion chamber. If the threads are few, you won’t get good combustion since the spark plug can’t project into the chamber. If there are too many, and the spark plug is longer than usual, it may get damaged by the pistons when the engine is running or the fuel will ignite sooner than expected. To get the right size, choose the one that’s the same size as your motorcycle’s original spark plug. 

Heat Range

This is the speed at which the spark plug can transfer heat from the firing tip to the cooling system. It can be used to tell the amount of time that a spark plug can withstand heat combustion before it gets damaged. The heat range is typically displayed in numerical figures in your owner’s manual. Most motorcycle spark plugs have a heat range of 900 to 1,500 degrees Fahrenheit. 

Other Considerations

  • Compatibility. Make sure that the spark plug is compatible with the make and model of your motorbike as well as the engine type. Also, consider the compatibility with your fuel.
  • Functionality. Consider the features of the spark plug and how it can improve your engine’s performance. This is in regards to fuel economy, ignition time, and power efficiency. 

Best Motorcycle Spark Plugs Reviews & Recommendations 2021

Best Overall
NGK Iridium IX Spark Plugs

These NGK Iridium IX Spark Plugs are a set of genuine OEM spark plugs that come pre-gapped and threaded to fit in most Harley-Davidson motorcycles. They have an iridium tip, which means they can achieve fast and effective ignitions with consistent sparks. The iridium conduction tip is laser welded and can last for about 60,000 miles. They are designed to reduce voltage requirements and consequently prolong the life of your ignition system.


The spark plug has a unique long insulator nose to prevent fouling of the plug tip, engine misfires, and natural deterioration. It’s also 25 percent smaller than most platinum electrodes to help deliver up to 3 horsepower. The plugs are metal plated for advanced anti-corrosion and anti-wear properties. In addition, they can withstand extreme heat conditions and are, therefore, suitable for performance enthusiasts.


A downside to the NGK spark plug is that it’s highly reactive, and despite the long insulator nose, the plug tip still fouls up easily in carbureted bikes. It’s also more expensive than standard spark plugs. 

Best Value
E3 Spark Plug Powersports

The E3 Spark Plug Powersports is designed to enhance the performance of your engine by providing a healthy power boost. It features a double DiamondFire ground electrode, which enhances the amount of combustion pressure that results from each power stroke of the engine. This translates to improved fuel economy, enhanced power output, reduced emissions, and faster starts. 


Faster flame ignition by the dual ground electrode results in optimal combustion of the air and fuel mixture. This means that your bike will experience smoother acceleration and idle. It's also designed with colder heat ranges than your original spark plug, so it can handle intense conditions in the engine and allow for performance modification. 


However, the spark plug may not be compatible with motorcycles whose factory spark plug has a large gap. Manually increasing the gap to fit the models could potentially reduce the efficiency of the double electrode. Despite that, it works well in gasoline-powered automobiles, snowmobiles, watercraft, trucks, lawnmowers, chainsaws, and most Harley-Davidsons.

Premium Pick
Denso Platinum TT Spark Plugs

The Denso Platinum TT Spark Plug features cutting-edge technology for extended reliability and enhanced performance. It comes as a set of six spark plugs, each with twin-tip technology for optimal ignitability. They are manufactured with an advanced 360-degree, laser-welding process for utmost threading precision. 


The spark plugs are designed with a titanium-platinum construction. The ground electrode is constructed with a titanium-enhanced alloy to minimize tip erosion and to extend the lifespan of the spark plug. The central electrode is made of platinum for enhanced conductivity and superior spark performance. 


However, this spark plug is not designed for every motorcycle. You need to confirm if it’s the right fit for your motorcycle’s make and model before fitting it. Also, you may need to regap them in less than a year.

Best OEM Replacement
NGK Spark Plugs - Standard

The NGK Standard Spark Plugs are a factory part for many bikes, so if you're looking for an OEM replacement plug, this is the way to go. As the name indicates, they are standard plugs with excellent reliability, power, and workmanship. 


These NGK plugs have a deep-seated copper core and work well in a wide temperature range, preventing fouling and pre-ignition. They provide good heat dissipation and electrical insulation due to their high alumina ceramic construction. The nickel alloy tips also promote a longer lifespan. These plugs fit perfectly, are easy to install, and you may not need to gap the plugs because they are already pre-set within the recommended spec. 


However, depending on what type of bike you ride, you may need to modify the ignition wire to fit the plug-in properly.

Honorable Mention
Accel U-Groove Spark Plugs For Harley Big Twin / Sportster

The Accel U-Groove Spark Plugs For Harley Big Twin / Sportster are specifically designed for 1986-2021 Harley-Davidson motorcycles. Sold as a set, these plugs have a patented U-shape design in the electrode that makes a wide, hot spark that starts standard and high-compression bikes. 


You don't have to worry about flashover or overheating in high-performance bikes and long-range situations because the plugs feature a sintered alumina heavy-duty five-rib insulator. These copper/nickel alloy plugs are foul-resistant and dissipate heat well due to their construction. They also have an electric seat heal to minimize leakage. Users report that these plugs can improve start-up as well as performance. 


One downside is the gap may not be to your Harley's specifications. This means if you're on the road and don't have the right tool, you won't be able to swap them out. Fortunately, they're easy to gap, and they thread easily and quickly.

Honorable Mention
Pulstar Spark Plug

Enerpulse Technologies, the company behind the Pulstar Spark Plug, promises that these plugs will provide a faster throttle response, smoother idle, better fuel economy, and higher-than-average horsepower and torque. The plugs use plasma-assisted combustion technology to achieve these goals. They have a patented internal capacitor developed with assistance from a U.S. Department of Energy laboratory. 


The high-intensity electrical pulse ionizes the air/fuel mixture and injects it with combustion-enhancing plasma, which in turn ignites fuels, quickly burns it, and maximizes a vehicle's horsepower, torque, and throttle response. Users report experiencing a significant improvement after installing these plugs. Overall, your bike should perform better, start easier, and reach idle RPMs quicker. It's an excellent low-cost improvement because they are reasonably priced.


Your bike may idle high after installing these plugs, but that's an easy adjustment. Also, the increase in horsepower may be negligible to some users.

Honorable Mention
PRO BAT D8TJC D8TC 3 Electrode Spark Plug

PRO BAT's 3 Electrode Spark Plug is designed for off-road and all-terrain bikes with 125cc, 150cc, 200cc, and 250cc engines, mopeds, and ATVs. They come in a pack of two, are easy to install, and feature a 12mm diameter thread and 19mm thread length. Designed to improve engine performance, these spark plugs feature a special electrode material that provides a strong spark, enhances fuel efficiency, reduces emissions, and is long-lasting. 


They are good, high-RPM plugs that are reliable when it comes to high compression and heat. They quickly fire up a dirt bike and are a reasonable price overall in comparison to other brands. The three-prong construction also appears to improve mileage and compression. 


However, if exposed to moisture, they may rust. Some users have also received faulty units, so be sure to inspect your products upon their arrival.

Honorable Mention
Autolite Xtreme Sport Iridium Powersports Spark Plug

The Autolite Xtreme Sport Iridium Powersports Spark Plug meets or exceeds OE expectations and is designed for use in motorcycles, ATVs, jet skis, snowmobiles, and more. It has an iridium-enhanced 0.6mm fine wire design with a platinum sidewire, which improves horsepower, efficiency, and durability. 


These plugs also improve ignitability and performance. They're designed to prevent fouling, so your bike is more likely to start regardless of the temperature. According to Autolite, the plugs provide quicker engine starts in comparison to rival standard plugs. Their use also results in less battery/starter wear and kick-starting force needed for dirt bikes. 


However, not all users have had successful cold starts using these plugs. Also, some other options may be of better quality for the price.

Tips

  • If you don't have an owner's manual, you can find out which spark plugs fit your bike by searching the year and model online. You can also measure the gap of your motorcycle to determine the size of the spark plug needed. Remember that spark plugs are not one-size-fits-all, and specific measurements are needed in order to make the best choice for your bike.
  • Once you know what type of plug you need on your bike, you can upgrade to a platinum or iridium option. Just make sure they fall within the manufacturer's recommendations.
  • Determine how many spark plugs you need. Most spark plugs come in packs. Once you find a brand that works for your bike, consider buying in bulk to save money. 
  • Evaluate how many times in the past you have changed your spark plugs. This will give you an estimate of how long the plugs are expected to last. 

FAQs

Q: Can I change my motorcycle spark plugs myself?

Yes. This will save you money in the long run and it is not very difficult to learn. Changing your own spark plugs ensures that your motorcycle maintains peak performance levels and allows you to maximize gas mileage. Changing your spark plugs requires the right tools, the right spark plugs, and a basic background and understanding of what the end goal is.

Q: How often should I change my motorcycle’s spark plugs?

This varies depending on how often you ride your bike, the distance you cover, and the age of your motorcycle. Regardless of your riding habits, it’s important to inspect your spark plugs on a regular basis.

Q: Does the material of the spark plug matter?

Spark plugs ignite sparks, and different metals do so at different levels. Spark plugs can have platinum cores, copper cores, and even be nickel-plated. 

Final Thoughts

Our top pick for motorcycle spark plugs are the NGK Iridium IX Spark Plugs. They are high-performance iridium plugs that improve the starting power and fuel efficiency of your bike. For a more budget-friendly option, consider the E3 Spark Plug Powersports.