Is your plug okay? Enjoy riding with the best matching plugs!


あなたのプラグは大丈夫?ベストマッチなプラグで快適ライディングを楽しもう!What perspective do you use when choosing plugs?

Genuine plug for peace of mind
Iridium with a higher price tag
The same ones that are used by others
After checking the heat value and other factors.

I'm sure you choose plugs for a variety of reasons, but I think relatively few people, especially those who "check the heat value and other factors" before choosing a plug.
In fact, this act of choosing from the heat value and other plug specs: ......

It's insanely important.

If you're a regular learner and ride by example, you may have no problem with the stock plug.
However, each rider has a wide variety of riding styles and habits.
You can shorten the life of your car if you don't choose the right plug for your ride. ......

So what exactly is the right plug for you ......? So, if you're wondering how to choose the right plug, we're here to show you how!

What does a plug do in the first place?

Do you guys know how the plug works?
The plug is the part that generates a spark by the electric current, and it is a very important part of the engine that sparks the compressed mixture (a mixture of air and gasoline) inside the engine and makes it explode, producing the energy needed to move the bike.
At this time, the plug has over 20,000 volts of current flowing through it, so the pressure from the high voltage and the explosion of the mixture is constantly being applied, and this is the part of the plug that is most loaded.

It is a part that is constantly under load, so of course it needs to be replaced periodically.

What is the life of the plug?

The basic principle of plug life is to replace the plug when the electrodes are rounded off from their corners.
The recommended time to replace standard plugs is between 3,000km and 5,000km for standard plugs, around 5,000km for iridium, and 8,000km to 10,000km for NGK's Moto DX plugs.
But from what users have told me, the standard plug was fine for 20,000 km! However, it is recommended to check the plugs once you reach the specified distance because you can't get 100% power out of them.

However, if the area around the electrodes is white or completely black and damp, the fuel in the mixture may be thick or thin, and we recommend that you also maintain the fuel area.Of course, the plugs will have to be replaced.

Let's review the plug changes!

Next, I'll show you how to replace the plug!
If you want to know how to do this in detailIYou can get the hang of it by looking at

There are different ways to access the plug depending on the vehicle type. Some vehicles just remove the plug cap, others require you to remove the fuel tank to remove the plug cap, etc. .......
The first procedure is different, but once the plug cap is removed, the rest is the same for all vehicles.
All you have to do is remove it with a plug wrench, right? Some of you may think that this is the case, but it's not.
The plug cap covers the plug hole to prevent sand, pebbles, rainwater, etc. from getting into the plug hole, but with age and rain exposure, there is a chance that sand and other debris can get into the plug hole.
And if you remove the plug as is, sand will stick to the female threads of the cylinder head and damage the female threads when installing the plug.
Worst case scenario is that sand can get into the combustion chamber .......
To prevent this from happening, clean the plug area with a compressor or air pump before replacing the plugs.
Once the plug is removed, you can assemble it in reverse order and the work is complete.

    1. Remove the plug cap.
    2. Clean the plug area.
    3. Remove the plug.
    4. Replace with new plugs.
    5. I'm going to install what I removed in the reverse order.

That's all. What you are doing is very simple.

Let's understand the plug structure!

Next, let's take a brief look at the construction of the plug.

Central and outer electrodes
This is the most important part of the plug, the part that allows the mixture to ignite.
Although nickel alloys are used in standard plugs, a number of plugs using iridium alloys and platinum have recently been released to improve starting performance and fuel efficiency.

As you may have heard in science class, insulators are things that do not conduct electricity.
The plugs are mainly made of ceramic and have excellent insulation, heat resistance and thermal conductivity.

The stepped area at the top of the plug is called the corrugation.
This serves to increase the distance between the terminal (top of the plug) and the main fittings (middle of the plug).
This prevents a condition called flashover, which is the discharge of electricity from the main fittings and other parts.

This is the part that contacts the plug cable cord and is an important part of the plug that receives the voltage created by the ignition coil.
The terminals come in a variety of shapes and sizes and are mainly used on bikes, either separated or threaded.

I didn't know anything about plugs! If you're wondering what to do if you don't want to do it, it's generally OK if you understand the part I've explained in this article.

What's the difference between an iridium and a regular one?

The "iridium plugs" that I see when I'm looking for a plug. Do you often see comments like this as a user's reputation?

High performance plugs!
My power's up.
Improved fuel economy.
Low speed torque is up.
It's true that changing from stock to iridium can improve fuel economy, but technically speaking, it's not.The power is not increased.
So why did you feel like you had more power ......?
The reason for this is very simple: the electrodes are sharp, so the discharge can be concentrated at a single point.

This way you can always have a stable ignition even at the time of starting or idling when the power is weak.
To use a simple analogy, it's like you're constantly hitting it with the exact core of the bat.
It's not an increase in power, but it's a solid way to give 100% of your power.

Extra: What is NGK's Moto DX plug?

Here's the name ......, which I glimpsed earlier when I explained the life of the plug: .......
The Moto DX is a plug that uses a material called ruthenium for the electrodes and the shape of the outer electrodes is made into a special shape called the "D-Shape" so that the intake and ignition efficiency is improved even more than the iridium plug.

In other words, they boast higher performance and longer life specs than iridium. Of course, it's more expensive, but there are good reasons why it's more expensive.

What is the "thermal value" in the specs?

The heat value is a numerical expression of the cooling properties of the plug itself.
The plug is the part of the plug that is most likely to get hotter because of the constant exposure to the flame from combustion.
Since the heat resistance is high, the plug will not melt, but if the temperature of the plug itself exceeds 950 degrees Celsius, it will cause a symptom called "Preignition," which is the automatic ignition of the air mixture without sending sparks away.
If this preignition occurs, the temperature in the combustion chamber can jump, and in the worst case scenario, the piston can melt or puncture.
When this happens, the engine is useless: .......
'Well, then, just use a cooler plug to prevent plagniation!
It is true that if you cool it down, the pre-ignition won't happen, but if you cool it down too much, this time the sparks won't fly properly and the engine will stall.

To prevent these, manufacturers choose and install the best plugs.
However, the factory plugs may not be suitable for vehicles that have been tuned and modified from the factory ECU settings.
This is where the "thermal value" comes in for reference.

There are many people who may not be familiar with the number "Heat value: 7", but once you understand this number, you can start to understand the best plug for your application. Specifically, this is how it works.
The lower the heat value, the lower the cooling property of the plug itself (burning type).
The higher the heat value, the better the cooling property of the plug itself (cold type).
High RPM engine vehicles such as supersports and 2-stroke bikes use plugs with high cooling properties and high heat value numbers.
On the other hand, a plug with a low heat value will be used for street bikes that run fast and easy.

In the end, if you had to choose, what would you do?

After all, as long as you aren't tinkering with the engine or anything else, you don't need to force the heat value to change.
Try changing the material of the electrode part to iridium or other materials first to feel the effect before changing the heat value.
By increasing or decreasing the thermal value, you should be able to find the best match for your plug.

Standard plug for price and cost performance.
Iridium plugs for better starting performance at a higher price.
I don't care if it's pricey, I'm a performance nut! Then the Moto DX plug.

If you're not sure about choosing a plug, you might want to think about this with this in mind.

Finally, here's a Webike staff recommendation for a plug maker!

NGK:Nippon Special Pottery Co.

They are the leading plug manufacturer in Japan.
Most vehicles come standard with plugs from this manufacturer.
It is also used in races and many riders use it in MotoGP.
*Webike has basically every NGK plug in stock!



A plug manufacturer that is so well known in Japan that it is called the bipolar of NGK and DENSO.
We offer a wide variety of iridium plugs to suit a variety of applications.


BRISK: Brisk.

Brisk was founded in 1935 in the Czech Republic, and is primarily involved in the development and production of spark plugs and sensors, which are used today by a wide range of European vehicle manufacturers both as original equipment and as OEMs.
Recently, he has been involved in the LGS series, which was co-developed with Lamborghini, and in various motorsports.

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