How much piston damage is ok for dirt bikes?

Pistons are damaged due to many causes, but ignoring them will wreck your dirt bike for more time. When the piston rings are cracked or broken, it starts producing sounds like hammering or tipping.

This sound is an indicator to change rings. Today we will discuss how much piston damage is ok and how do you know that piston is out or service.

Read this article till the end and know each necessary points regarding destructive pistons. 

What is a piston in dirt bikes?

The piston is a part of the engines to transfer force from gas present in the cylinder to the bike’s crankshaft to make it work.

If you talk about its shape, it looks like a short cylinder body adjusted in a cylindrical chamber with a sliding piece moving upward and downward.

In a simple word, we can say a piston is not only a part of an engine. It’s already an internal combustion engine.

The piston acts as a seal between the cylinder and the combustion chamber to complete the combustion process.

Pistons are made up of small rings to complete a structure of perfect seal to resist extra air-fuel mixture leakage into the chamber.

Want to know the working of Piston ring then you must read the article how does piston ring works?

How To Know About Damaged Piston?

When you come to know that it’s time to visit a doctor when someone feels sick, in the same way, your piston shows some signs of damages.

Here, we have mentioned a few points which will help find how much piston damage is ok. 

Low Performance-

When Pistons are damaged, it takes more time to start the engine, and every function of the dirt bike starts working slowly.

When pistons are broken from somewhere, they can’t deliver or deliver prolonged force to the crankshaft, and without enough power, the combustion process doesn’t take place correctly.

As a result, the whole performance will be killed just for a faulty piston. Or even a damaged piston can be a cause of backfiring, which may scare you. 

Smoke From Exhaust-

You know very well what a piston does. It restricts extra fuel to fall into the combustion chamber.

But, if it doesn’t work well, fuel will start leaking to the chamber. And the lousy ratio of air-fuel smoke results from exhausting pipes.

More than the ratio, the fuel starts burning, and at last, it produces a thick, blue-grey smoke that smells so hard. If your dirt bike is showing this kind of smoke, please check your piston at least once. 

Consume More Fuels-

Yeah, if a piston can prohibit fuels to reach the combustion chamber. You need to fill it repeatedly, as leakage keeps happening and burning, more the smoke released from the exhausting system.

You can’t ride your dirt bike for a long distance with a full tank; after 1000-15000 miles, you keep putting more oil into the tank. If your dirt bike shows frequent fuel consumption and time to change the piston, visit a mechanical centre. 

Bad Acceleration Power- 

When the piston is damaged, it loses power, and less compression takes place. When you put your foot to accelerate your dirt bike, your Bike responds so late.

This is one of the indications that you need to change your piston rings. A damaged piston won’t compress or deliver enough force to speed up the power which your dirt bike needed. If you are noticing the same, don’t ignore and visit a mechanic. 

These points are really helpful and save further damages or backfiring. But, how do you know to replace the piston before it goes worse? Don’t worry; below are the few tips for different stroke dirt bikes. 

How Often You Need To Replace Piston?

Usually, replacing a piston depends on the riders if you are a racer and using a four-stroke dirt bike to ride.

After every 15-30 hours of four-stroke, you need to change the piston, which means you may complete six or seven races at that stroke.

Whereas in the case of two-stroke dirt bikes, the piston lasts a little bit longer.

But, it’s a suggestion given by the mechanics that at the end of the day, please check pistons, is there anything broken or torn. Also, if you are a normal rider, use bikes for daily purposes, so replace pistons after every 30000 Km (18642 miles).

As you can’t use a toothbrush for your whole life, you can’t stay on the same piston for a long time. 

How much piston damage is okay?

You came to know the symptoms of the damaged piston, but to ignore any such signs, why not change the piston earlier.

Let’s see those major points with which you will tell you how much piston damage is okay. 

Ring Gap-

Keep checking ring gaps of a piston; due to more heat, it expands, and more gap occurs between the top-notch and the ring. 

Clips or Spirelocks-

Inspect the clips; if it looks tight, then no issue. But, if there is any small gap or cut, that means it will damage the piston soon. Throw it away and fit the new one. 

Piston Diameter-

With time, the piston gets thinner, and in the end, it will break it. If its diameter is about 0.001″ to 0.002″, then it’s okay.

But, more than this means the piston has lost its resisting thickness and is soon unavailable to work. 

Smoothness Rings Movement-

Try to move the ring with your fingers if it smoothly moves around. You can still use your piston, but what if you need to push it harder somewhere to move. This is the sign of welded rings or broken ones. 

Discolouration of Piston-

Turn the piston and see the backside; if it turns into black, dark purple, blue, grey or any dark colour, it means the piston crown has faced a lot of heat and died. 

Time to replace such a piston will be a smart move. If you are still using the same, it can destroy the balanced ratio of air-fuel. 

If you notice any given changes in the piston, it means the patient is counting the last seconds of life. Changing it will rescue many further causes. 

How To Replace The Faulty Piston?

You find the causes, last stages symptoms and timing of replacement too. But, what if you need to change it at random at any place. Be ready for such situations to help you below have given about how to replace the faulty piston.

Remove the parts-

To change piston rings or piston, you need to remove the cylinder head. Later, dry the coolant and also remove exhaust manifolds by losing the bolts.

Now, remove connecting wires which helps deliver fuels and then separate plug wires. The last step is to put out the rocker arms and pushrods. Once you have done all procedure, you can remove the head easily. 

Clean the Piston-

If you need to change piston rings, clean the piston by covering whole holes to avoid further dust.

But, if you need to change the whole piston, then it can be installed easily. You can use kerosene oil for a smooth fitting. And also clean all the other opened parts. 

Remove Old Piston Rings- 

In the case of piston rings, remove each ring using piston ring tools. Once you have removed all rings, it also needs to be cleaned. Put it in kerosene oil for six hours at least. But, if you want to change the whole piston, you need to do this step. 

Install Piston Rings-

If you have ever bought a piston, have you seen rings are not fitted inside the piston? Mechanics do it one by one, so you can consult a user guide.

Whenever you install piston rings, place them at proper orientation. The first ring you need to install is called an oil separator ring; later, install an oil wiper ring unidirectional and either side of the oil separator ring.

This step makes the piston a perfect seal. Now, time to fix the top and end compression ring.

You will notice a circular cut above the oil separator ring place; install the end compression ring there, make sure the direction is correct.

In the end, fix the top compression ring at the top of the piston head and then lock it carefully.

Before installing the piston in your dirt bike, lubricate it enough for smooth movement. 

In this way, you can replace the piston or piston rings by yourself. But, if you still don’t have an idea about the mechanical terms, don’t touch it.

First, know the proper terms and steps by visiting the repairing centre, then you can make it possible for the next damage.  

Is Piston Expensive To Replace With the New One?

If I’m going to say that it’s not true, it means I’m cheating on my readers. In reality, piston costs higher, $30 to $150 for each piece. But, most of the time, you just need workers to fit the power expansion.

Labour or mechanic takes about $150 per hour, and to replace the piston takes about 10 hours, so you can think this would charge you higher than your expectations. 

What To Do Not Do When Piston Is Damaged?

You can’t ignore the default piston; if you do so, definitely bad consequences will follow you. Then what you need not do for any kind of extra damages. 

Don’t ride Bike- 

When you know or see any symptoms that indicate a damaged piston, don’t risk bike riding. 

Park Under A Cool Area-

As I told you, if your Bike gets too hot, it can burn the back part of the piston and hence park the Bike under a cool area to avoid backfiring. 

Don’t Add Any Kind of Lubricant- 

Sometimes, you may see the above symptoms of the bad piston. But to ignore those signs, you add ethanol, lubricant or fuel to reduce broken piston noise. Your such steps can worsen the situation and destroy the engine as well. 

These small suggestions can save your life as well. A dirt bike is easier to ride, but everything has benefits and loss too. Excessive use of a damaged piston can lose your pocket. You must know how much piston damage is okay and what to do with the damaged one. 

Note:- If you are a new rider and have no idea about dirt bike’s mechanisms. It is better to not touch internal parts of the Bike. Don’t give a chance for the experiment; dirt bikes are really expensive, so visit the mechanics. 


Everyone wants their Bike’s engine to last longer, but do you know if you ignore even single damage can destroy your Bike soon.

Here, you have read how much piston damage is okay and the signs to replace the new one to save the engine.

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