How to Perform Motorcycle SPARK PLUG Maintenance

Spark plugs are a fundamental part of your motorcycle. We can define spark plugs as the window of the engine and an invaluable diagnostic tool, since they show the symptoms  and performance conditions of the engine. It is important to know how to take care of them and always have them in optimal conditions for the proper functioning of your faithful friend. We understand that you want to have your motorcycle in perfect condition, and for this you must take care of them and know when and how to maintain spark plugs . We are going to tell you everything you need to know about this piece as important as it is unknown, let’s go!

Index of contents

What is a spark plug, how does it work and what is it for?

motorcycle spark plug maintenance

Of all the parts of the motorcycle , the spark plugs are in charge of starting the machinery. They really fulfill 2 very important functions:

  1. Ignite the air-fuel mixture
  2. Remove heat from the combustion chamber

The spark plug, in addition to providing the spark to said chamber, works by exchanging heat, extracting unwanted heat energy from the combustion chamber to the engine’s cooling system.

In the previous process, the thermal range of the spark plug intervenes, which is its ability to dissipate heat in the combustion chamber and take it to the cooling system and is determined by the length of the central ceramic insulator, its ability to absorb and transfer the heat of combustion, the insulator material and the central electrode material

The thermal range of a spark plug has no relationship to the current voltage that is transferred through it.

When to change the motorcycle engine spark plug

motorcycle spark plug maintenance

With use, spark plugs suffer electro-erosion, which causes wear on the electrode and increases the spark jump distance, so the spark plug will require a higher voltage to cover said distance and as a consequence when accelerating we will lose some engine explosions causing wasted fuel and loss of power. Depending on the type of spark plug we use, its change interval will be different since its durability goes hand in hand with the number of electrodes and the quality of the gasoline we use.

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average kilometers

The average number of kilometers to change the spark plugs on your motorcycle is specified in the machine’s instruction books, but each brand is different and it is very common to find disparate data. On average, it can be said that the spark plugs should be replaced with new ones every 30,000 kilometers, approximately.

They last more or less depending on the use of the engine

It is true that motorcycle spark plugs can last twice as long, and also that it is necessary to change them before. This is due to the good or bad use you make of your motorcycle, which will determine whether you should replace them sooner or later. If you make good use of the engine and do not rush the gasoline tank, the spark plugs can last twice as long, up to 60,000.

However, if there is an electrical failure, a bad fuel mixture, or they are stained with oil, you must replace them immediately, regardless of the kilometers you have gone without doing so. Therefore, you must locate the spark plugs in your vehicle and check them periodically, to know when to replace them.

How to change motorcycle spark plugs

how to change motorcycle spark plug

Changing the spark plug or spark plugs on the motorcycle is important and if you do not carry out this maintenance work on your motorcycle, you may notice that it loses power, consumes more fuel than usual or even fails to start. Although it is a relatively simple operation on many models, you must be careful when performing it to avoid breaking the part or burning yourself if you do not wait for the motorcycle to cool down completely. At we explain step by step how to change motorcycle spark plugs. Let’s see the process of changing a spark plug :


hand tools

  • clean rag
  • Wire brush
  • Spark plug socket and ratchet wrench
  • Spark Plug Gap Tool

#1 Remove the wires

how to change motorcycle spark plug

The first thing to do is wait for the engine to cool down. Use your fingers to hold the connecting wire and disconnect the spark plug. Gently twist the cable until it is free, do not force it otherwise it will be damaged. Repeat the process with each spark plug.

#2 Clean the spark plugs

Use a little detergent and a damp cloth to scrub the spark plugs clean before removing them. This will help you prevent any dirt or metal debris from falling into the engine cylinders. You can also use a pneumatic compressor to blow air over the spark plugs.

#3 Take out the spark plugs

Turn the spark plugs counterclockwise. Once you have removed the spark plugs check if they are damaged. Normally a broken spark plug releases metal debris that can fall into the cylinder head.

#4 Check the cylinder heads

It is always a good idea to check the cylinder heads before installing the new spark plugs. Newly purchased spark plugs should easily fit into the cylinder heads. If the heads are dirty, wipe them with a cloth moistened with a penetrating oil. This also benefits engine ignition. Drizzle a little oil over the cylinder head to stop any chance of rubbing when installing the new spark plugs.

#5 Install the new spark plugs

Put the new spark plugs in place using first your hand and then a wrench. Keep in mind that you should never overtighten them as the engine will not start efficiently.

#6 Put the cables back

Carefully reattach each wire to the specific spark plug using your fingers. It is very important to put the wires back in the correct sequence on multi-cylinder engines, otherwise the motorcycle will shut down soon after starting, or may not even start at all.

motorcycle spark plug maintenance Tips

  • Do not change spark plugs with a hot engine.
  • Spark plugs are very sensitive so be careful not to drop the new ones on the ground to avoid damaging them
  • When changing them we will make sure that we place each cable of each spark plug in the place that corresponds to it. If we have to mark them to remember the order they are in, we will. If we make a mistake in the order of the cables, the motor will not work properly.
  • Before removing the old spark plug, we will clean around it well to prevent dirt from entering the connectors.
  • Always use wrenches suitable for the size of the spark plug used by your engine model. Remember that to loosen, turn counterclockwise and to tighten clockwise.
  • When screwing in the new spark plugs, we can grease the thread a little to avoid the risk of damaging the thread and facilitating subsequent spark plug changes.
  • Do not force when removing the cables, or pull directly on them to remove the connectors. If it is difficult for you, try to remove them by rotating them, taking them directly from the connector’s protective case
  • When tightening the new spark plugs do not force them too much. As long as they are tight it is enough (never leave them half loose)
  • We will always replace all spark plugs at the same time
  • The spark plugs may just need cleaning. They are cleaned with a wire brush.
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Conclusion: Check from time to time the spark plugs of the motorcycle

To increase the duration of your spark plugs you must make good use of the engine, avoiding subjecting your motorcycle to excesses that make it suffer too much. Another good advice is not to rush the fuel and keep them clean and checked frequently.

If you notice your bike losing power, take a look at them. You may be facing problems of wear, carbonization, mechanical damage, or excessive temperature. Careful spark plugs can last twice as long and that can be… about 60,000 kilometers!

You no longer have an excuse, at the slightest suspicion of problems with the spark plugs … change them! Now you know how!

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