Best Spark Plugs for Harley Davidson to Keep Running Smoothly

Do you want to enhance your Harley engine performance? Then you’ve got to look into the best spark plugs for Harley Davidson for sure.

Why’s that?

Most people don’t get that the spark plug plays a huge role in bikes’ performance than they ever give it credit for.

best spark plugs for harley davidson

From giving you that quick ignition to helping to burn the engine fuel clean to increase the engine operation, a lot of the things can be improved with this small piece of equipment.

Maybe squeezing out more power and acceleration all you need is a new spark plug.

So, check out the latest best spark plugs for Harley Davidson Evo rides to do that.

If you’ve set your mind to get the best deal of the best spark plug out of the lot, then check out the options below.

best harley spark plugs

Champion Spark Plug


For the best pick spark plug, I will go with the Champion RA8HC. It gives you that stable performance on the higher RPM engines that you need. And with its copper electrode, it can ensure to get that super fast spark to get the engine running unlike anything else.

best spark plugs for harley sportster

E3 Power sports Spark Plug


Besides the two, the best choice spark system is the E3. It is for those more demanding Harley Davidson rides. With its universal fit, it is much easier to get installed on any ride. Plus, the extreme performance enhancement of it, whether it is the horsepower or the smoothness of acceleration, makes riding a lot more fun than most others.

budget pick

Briggs & Stratton Spark Plug


If you want a budget option, then you can go with the Briggs and Stratton one. It gives you that durable platinum build to get longer miles service. Not to forget, it helps to reduce the carbon buildup which makes it a fuel-efficient option that’s good for the environment.

Quick Comparison: Top 10 spark plugs for harley davidson

best spark plugs for harley

Champion Spark Plug RA8HC for Harley-Davidson

best spark plugs for harley davidson

ACDelco 41-993 Professional Iridium Spark Plug

harley davidson spark plugs

E3 Spark Plugs Power sports Spark Plug

Spark Plug

4 New NGK IRIDIUM IX Spark Plug

best spark plugs for harley davidson

Briggs & Stratton Spark Plug Platinum

5 Best Spark Plugs for Harley Davidson

Want the best spark plug for your Harley Davidson? Then go and check out the list below as I’ve got some of the best ones right here.

1. Champion Spark Plug RA8HC for Harley-Davidson

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To get your Harley Davidson’s engine up and running, you need a champion spark plug. And to find that champion spark plug, you should look no further than the Champ itself.

The RA8HC is one of the best Harley spark plugs in the business with premium quality that is quite incredible.

Why will you like this product?

The best spark plugs for Harley 103 gets made with the best material for the part. You’ve guessed it right: Copper.

The material is the most proficient conductor of current. Not only that, it gets the heat to move faster to ignite the fuel to get the engine to produce the power.

But having only a copper spark plug won’t be enough. Due to its low melting point, it would get worn out real fast. That’s why Champion worked a way around it with the nickel alloy cover to make it last for long.



What’s the thread size of the spark plug?

The Harley spark plugs from champ got a 12mm thread.

What's the most impressive feature of the spark plug?

The 5K Ohm resistor does an awesome job of keeping the ignition noise down.

2. ACDelco 41-993 Professional Iridium Spark Plug:

Want your Harley Davidson’s engine to get started right away, even in extreme cold conditions?

Then you should go and get yourself the ACDelco 41-993 spark plug. This top of line spark plug for Harley is one of the best. Don’t believe me? Check it out for yourself.

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Why will you like this product?

When it comes to response, the iridium spark plug like the ACDelco is second to none.

Unlike other materials, it can endure extreme heat and pressure. So, from the engine combustion, the Harley spark plug won’t get damaged. That’s why for the gas-fueled engines, it is the top choice.

Not only that, there is no carbonizing effect on it even from long time use. It will keep that electrode gap to ensure clean burn even after years.

And can’t forget about its voltage conductivity. It works with safe efficiency in lower voltages.



How many spark plugs do come in the pack?

You will get a total of 8 best ACDelco spark plugs for Harley Sportster within the pack.

What’s the one feature that stands out the most?

Without any doubt, the efficiency of the spark plugs made by ACDelco is one of its key selling points. It uses lower voltage to improve the performance of the ignition system. Not to mention, using lower voltages improves its life expectancy too.

3. E3 PowerSport Spark Plugs

For the Powersport bike engines, you need something more than the regular spark plugs. You need the E3 Spark plug.

No matter what Harley or other bikes you’re riding, you will get to fit it within your bike, thanks to its universal fit design.

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Why will you like this product?

If you know your spark plugs, you should know that copper is the king of the kings. No material conducts electricity to ignite and combustion going within the engine right away like the ones here.

Though the material is also infamous for its low melting point. Which however gets taken care of by the Alloy steel layer on top of it. Therefore, it gives you that longevity too.

But all things said, the spark plugs are the real deal for their capabilities to handle the racing engines. With its DiamondFire ground electrode design, it takes on the extreme vibrations and still manages to transfer quick heat to spark quicker than others.



Does it come with any warranty?

Yes, you will get a limited lifetime warranty on the E3 spark plugs.

What's the one thing that will impress you?

There are not one, but many things that might leave you in awe.  Take fuel burning for example. E3 helps with the complete burning of it to give a smoother acceleration. Not only that, it even helps to lessen carbon emissions. Also, the faster flame propagation improves fuel efficiency within the engine as there is less waste during burning.

4. New NGK IRIDIUM IX Spark Plug LTR6IX-11

How can you talk about spark plugs, and don’t bring up the name NGK?

Coming from WD Express, they’re one of the most coveted engine ignition parts out there in the business.

No surprise, when anyone asks who makes the best Harley-Davidson spark plugs, the name of it comes up again and again.

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Why will you like this product?

You are getting iridium as the center electrode with the plugs. From traditional electrode materials, this one is 25% smaller that makes it easier to install.

But the real benefit of it is that it requires lower voltage to produce the spark. So, you can get the engine started faster. Not to forget, there is less wearing due to it.

The NGK spark plugs breathe in new life to your Harley Davidson for sure. You will get a faster ignition, quicker and smoother acceleration for longer miles with it than most others.



What type of bike is the spark plug suitable for use?

It got a lower heat range, which means it is a hotter spark plug. So, for low RPM rides, it is much more suitable.

What's the coolest feature of the spark plugs?

The iridium electrode makes the NGK plugs what they are. You get a higher melting point spark plug that can give you a 25% longer lifespan than regular ones.

5. Briggs & Stratton Spark Plug Platinum

To get the maximum ignition performance, trust on the Briggs and Stratton spark plug. With a gold shell coating, you will have a longer-lasting plug with it. No more corroding to cause a hiccup with your engine starting anymore.

Want to know more about it? Then check out below.

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Why will you like this product?

With Briggs and Stratton, you will get one of the best platinum Harley spark plugs. You can be sure to get at least, 100000 miles using it without any wearing out or other issues. Longevity is what it offers to your bike engine ignition system.

Plus, with properly gapped plugs, you get to avoid skipped firing or pre-ignition issues that cause engine damages.

Even it helps to improve the bike’s starting power. You will get to ignite the combustion system faster with it. Not just that, it will even burn the fuel clean to address carbon buildup issues.



Is it more conductive than copper?

No. The spark plug doesn’t match the conduction level of copper. Though, it gives you much more durability over it.

What’s the top feature of the spark plugs?

From what’s been seen so far, the Briggs and Stratton spark plug helps to burn clean and maintain the carbon emission level standards.

How to pick the best spark plugs for Harley Davidson?

If you’re not happy with the stock spark plug system in your Harley and want to switch to new ones, then go for the above options. But which one to pick can be a conundrum in itself if you don’t know what traits to look for within the spark plugs.

No worries, I will take you through some key aspects that will help you make the decision.


The first thing you need to know about the spark plugs is the materials they use. Now, the market mostly got three types of materials.

You’ve got copper, platinum, and iridium. From the lot, copper is the best electricity conduction. But it is also the one that wears out quicker than most. This is why an alloy cover on it is quite crucial to get more use out of it.

On the other hand, platinum spark plugs are available in two variants. One is the single platinum, the other is the double platinum. Both are much more durable than copper. The double one is even more than the single platinum one.

But Iridium seems to be the one to go for if you want the ultimate service life from your spark plugs. That however comes with a higher price tag.


The spark plug gap is something that makes it great or not. So, what’s the gap?

It is nothing but the space between the center electrode and the ground one. If you’ve got the right gapped plug, there will be no engine misfires. And that will help to improve the fuel efficiency in the engine.

If you want, you can optimize the gap yourself in the spark plugs. Or if you don’t know what to do, then get the pre-gapped ones that would come ready for use.

Ground electrodes:

The number of ground electrodes bordering your center electrode can make the difference. That’s because the more electrodes you’ve got the more extended the spark plug’s lifespan will be. It is because, when one burns out, the other will still be there. Though it comes at a cost of your ride’s fuel efficiency.

So, you’ve got to make the call. Whether to get a single ground electrode plug or a double one.


Even the thread numbers play a significant role in the engine performance. If you’ve got a few threads on the plug, the combustion might not be best due to its reach to the chamber.

But if it’s too long, there is always the risk of it getting damaged by the engine’s piston or the fuel pre-ignition.

To get the right size spark plug, check out the original plug’s thread and go for that number with your new spark plug.

Heat range:

Last but not the least, knowing what heat range spark plug to get will make or break the game.

If you get a hotter type plug for a higher RPM bike, that won’t work. You need to consider getting a colder type. Same way, if you get the cold type plug for a lower RPM bike, the performance drawn by the engine won’t be the best.

That’s why based on the bike, you’ve got to get the right type of heat range plug. The lower the number, the hotter the spark plug, the higher the number, the colder it is.

But remember, there is no universal heat range chart. Each brand has its own heat range scale. So, make sure to check with that before getting the spark plugs for your Harley Davidson.

Frequently Asked Questions:

How often to change the spark plugs?

It depends on how much distance you cover with the ride. Some spark plugs get made to give you 100000 miles. Where others can offer just 40000 miles before you need to replace them.

Does the material of the spark plug matter?

No doubt, it is one of the key features of the bike part. Depending on what type of material plug you get, you will have a different level of spark efficiency and durability.

What’s the best spark plugs for horsepower?

For those Harley twin-cam, the best spark plugs are the E3.

Is it possible to change motorcycle spark plugs on your own?

Yes, you can do that. It is not that hard with the many video tutorials and how-to guides out there today. Even spark plugs manufacturers have their manual showing how to do it.

Final Thoughts

By now, you’ve got the best spark plugs for Harley Davidson.

With a wide variety of options, finding the right one won’t be that hard. Just make sure, whichever plug you’re getting, it matches the same feature with the stock one to get the best performance out of the engine.

If you manage to do that, you will be fine.

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