Can You Use Car Spark Plug On A Motorcycle? – (Yes! But…)

A spark plug is an essential component of automobiles that runs on gasoline or petrol. It generates electric sparks in the combustion chamber to ignite the air-fuel mixture. Although all spark plugs look similar in design, they have different electrodes and thread sizes.

So, can you use a car spark plug on a motorcycle? A spark plug serves the same purpose across all automobiles – to ignite the air-fuel mixture. However, the spark plug’s thread size and electrodes differ for motorcycles and cars. You can not use a car spark plug on a motorcycle because the thread size varies. If you’re lucky that your car spark plug thread size matches with the motorcycle, you can interchange them in an emergency.

Motorcycle Spark Plug

Is There Any Difference Between Motorcycles And Car Spark Plugs?

Although a spark plug serves the same purpose across all automobiles- to generate a spark to ignite the air-fuel mixture in the engine’s cylinder. The spark plug’s thread size differs from cars to motorcycles, and the heat range is also different.

A motorcycle spark plug has a higher heat range than most cars. If you use a lower heat range on a motorcycle, you might face problems with engine performance. If your car’s and motorcycle’s spark plug has the same heat range and thread size, you can interchange them.

What Are Different Types Of Spark Plug?

There are three types of spark plugs used in motorcycles and cars:

  1. Copper
  2. Platinum
  3. Iridium

Although they serve the same purpose for your engine but they have different lifespans and prices.

1. Copper Spark Plug: A copper spark plug has high conductivity, so it’s mostly used in high-performance vehicles. Copper spark plugs are cheaper and have shorter lifespans (up to 20,000 miles). This spark plug is not used in cars and motorcycles because of less durability.

2. Platinum Spark Plug: A platinum spark has a higher melting point to withstand the engine’s high temperatures and combat carbon deposits on the tip of the electrode. That’s why platinum spark plugs last longer (up to 60,000 miles) than copper ones.

3. Iridium Spark Plug: In this type of spark plug, iridium metal is used as an electrode. The melting point and conductivity of iridium metal are higher than platinum. So, it has the highest lifespan and can last more than 100,000 miles.

Do Expensive Spark Plug Makes Any Difference?

Iridium spark plugs are better at starting the engine than other spark plugs because the spark is highly concentrated at the center electrodes. They also require less voltage to generate a spark and can withstand high temperatures without carbon deposits on the tip.

So, investing in premium spark plugs is worth the money as you won’t face problems starting your engine. Also, an iridium spark plug has longer lifespans that can last up to 100,000 to 120,000 miles without any issues.

How Do I Choose Spark Plug For A Motorcycle?

A spark plug should release the heat in a controlled manner. If the tip of the spark plugs overheats (high heat range), it may generate a spark before the completion of the compression stroke, which results in pre-ignition.

Similarly, if the heat range is too cold, the carbon deposits will not burn off from the tip of the plug, which reduces the engine performance and spark plug lifespan. You should always refer to your manufactures user manual while selecting a spark plug.

Can Wrong Spark Plug Damage Engine?

You’ll get less power out if you use the wrong spark plug in your motorcycle or car engine. Also, if the heat range is higher than the specified by the engine manufacturer, it may lead to pre-ignition, which results in major damage to the piston and cylinder head. So, always use the spark plug specified in the user manual.

Also, you do hit and trail with a low heat range spark plug and slowly increase it. Once you notice smoother power output from your engine, you can stick to that plug.

Can I Use Iridium Spark Plug On A Motorcycle?

Iridium spark plugs are best for motorcycles because they have higher melting points and longer lifespans. Iridium spark plug uses low voltage and generates a highly concentrated spark to ignite the air-fuel mixture. As a result, you get better engine performance and higher fuel economy.

If you own a sportbike, you can replace the platinum spark plug with an iridium one. But ensure that you choose the correct heat range as specified by your manufacturers.

Is It Okay To Use Aftermarket Spark Plug On Motorcycle?

There is no issue in using an aftermarket spark plug on the motorcycle. All spark plugs do the same work. However, when buying an aftermarket spark plug, please ensure to buy reputable brands like NGK and BOSCH. Also, ensure the aftermarket spark plug’s heat range is the same as the OEM spark plug.

Click here to check the price of NGK Iridium Spark Plug for Harley Davidson on Amazon


The car’s spark plug’s thread size and heat range differs from the motorcycles. So, you can not interchange them because a wrong thread size will cause leakage in the compression stroke. However, if both have the same thread size and heat range, you can interchange them.

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