Are you confused between a 2-stroke and 4-stroke dirt bike? Which stroke bike is better for you? This blog post can help you to choose between two-stroke and four-stroke bikes.
When we are new to the bikes or we are buying the first dirt bike, this question often passes in our mind as to Which stroke bike should I buy, 2-stroke or 4-stroke bike? Which is useful for a few years.
Before moving to know the difference between 2 Stroke and 4 Stroke dirt bikes, We need to know about stroke first in short. So let’s start.
What is stroke in Bikes?
A stroke is the movement (up or down travel) of the piston in the cylinder. A stroke occurs when the piston moves from TDC (Top Dead Center) to BDC (Bottom Dead Center), or vice versa.
TDC is a top position to which a piston can travel inside the cylinder, While BDC is a bottom-most position to which a piston can travel.
A 2 stroke engine completes a power cycle (the cycle of taking in fuel and delivering power) in two strokes (up and down movements). While a 4 stroke engine completes a power cycle in four strokes.
| # | 2 Stroke | 4 Stroke |
| Power | More power | Less power |
| Price | Cheaper | Higher |
| Maintenance | Low | Regular |
| Weight | Lighter | Heavier |
| Control | Overall Good | Very good |
Two-Stroke Dirt bike
The engine and body of the two-stroke dirt bike is simple or less complicated. A two-stroke engine needs only 2 strokes to generate power once. The two-stroke engine works on a very basic and simple structure. But it is still an effective and preferred engineering structure.
We know that there are only two strokes in a two-stroke dirt bike’s engine. So let’s know what happens in 2-stroke engines.
First Stroke: In a two-stroke engine, two actions happen in the first stroke. The oil and air mixer enter inside the cylinder through the inlet port and fuel is ignited by a spark plug. This process causes the expansion to move the piston down (bottom dead center) until the waste smoke reaches the exhaust port, an opening on the side of the cylinder.
In this way, oil inlet and fuel combustion are completed in one stroke.
Second Stroke: In the second and final stroke. Due to the combustion of oil, there is an expansion force causing the piston to move down. When the piston comes down, the fresh fuel and air mixture reaches the combustion chamber through the transfer port.
In this way, power is generated and at the same time, the action of the exhaust is also completed.
2 Stroke dirt bike Pros and Pros
Cons
1. More power
The engine of a 2-stroke bike generates more power than a 4-stroke engine. This is because 2-stroke bikes have fewer moving parts. So that the internal friction is reduced.
In other words, we can say that a 2-stroke bike takes 2 moments of the piston to generate power while a 4 stroke engine takes 4 moments. The same size two-stroke engine has almost twice the power capacity. That’s why we can say, 2-stroke engines are more powerful.
2. Lightweight
Generally, 2-stroke dirt bikes weigh less than 4-stroke dirt bikes. Well, there can be many reasons for being underweight, such as the design and compactness of the engine.
In some cases, it can be heavier than a 4 stroke engine.
The heaviest component of the bike is the engine. Which affects the weight of the bike. I am sharing below the table chart of the average weight of two-stroke dirt bike engines. The weight of the engine may vary from company to company.
| 2 Stroke Dirt Bike (by the engine) | Average Weight (lbs) | Average Weight (kg) |
| 250 CC | 228 | 103 |
| 125 CC | 209 | 95 |
| 85 CC | 165 | 73 |
| 65 CC | 128 | 58 |
| 55 CC | 104 | 47 |
3. Affordable
Parts of a 2 stroke bike are cheaper than a 4 stroke bike. Two-stroke dirt bikes have 30% to 50% fewer moving components compared to the four-stroke. This affects the price of the bike. 2 stroke dirt bikes are cheaper than 4 stroke bikes of the same power.
4. Low Maintenance cost
The parts of a 2 stroke bike are not very complex nor is it expensive. Because of this, its repair cost is less than a 4 stroke bike. Also, A 2 stroke dirt bike is easier to repair than a 4 dirt bike.
5. Quik Acceleration
Two-stroke generates more power so that quicker acceleration becomes possible. In other words, it can be said that minimum stroke is required to generate quick power.
Cons
1. Higher Fuel Consumption
A two-stroke dirt bike consumes more fuel than a 4-stroke dirt bike. Because fuel is consumed once every other stroke. Because fuel is consumed once every second stroke.
2. More vibration and noise
The engines of the two-stroke and 4-stroke dirt bikes are different from each other. Every time the pistons pull back, the combustion takes place. So the 2-stroke dirt bike engine is louder and vibrates more.
3. Pollution
Two-stroke dirt bikes cause lots of pollution which is not good for nature. Because in every second stroke the fuel combustion. A two-stroke engine produces more smoke. A cloud of smoke can often be seen when the motor is rotated excessively.
4. Shorter life
The lifespan of a two-stroke dirt bike is less than that of a four-stroke dirt bike. Due to the excessive movement of the piston, the engine makes knocking, and malfunctions occur in the inside walls and the piston rings.
5. Heats up quickly
As we know that in the two-stroke engine the combustion rate is high. So the engine gets heated up quickly. Coolant and lubrication oil are required separately to cool the engine, which increases the cost of oil.
6. Jumping too much
As we know that the weight of a 2 stroke dirt bike is light so that it jumps in off-road running.
Four-stroke Dirt bike
The engine and body of a four-stroke dirt bike are complex. A four-stroke engine needs 4 movements of the piston (four strokes) to generate power once. The four-stroke engine works on complex structures. But It is a very effective and much-preferred engineering structure for beginners.
We know that there are four strokes in a four-stroke engine, this stroke is as follows. intake, compression, combustion, and exhaust stroke.
Intake Stroke: This is the first stroke, In this stroke, oil enters the empty cylinder by a valve and the piston moves down. This whole process is called intake stroke.
Compression Stroke: In the second stroke the piston is moved upwards. The area of the cylinder is continuously decreasing as the piston is moved up. This process increases the pressure and temperature in the cylinder.
This greatly increases the temperature of the fuel and now the fuel is ready for combustion.
Combustion Stroke: In the third stroke, a spark from the spark plug ignites the cylinder which ignites a mixture of air, fuel, and oil. This whole process is called the combustion stroke.
Combustion stroke is also called a power stroke because power is generated in this stroke. Combustion has expansion power so that the piston is pushed down. The power generated is transmitted through the piston to the crank. A crankshaft is connected to the crank, which is used to generate rotational motion.
Exhaust: In the fourth and last stroke, the waste smoke from the cylinder is expelled through the valves.
Power is generated once during these four strokes. After the exhaust stroke, the intake stroke starts again. This process continues till the engine starts.
Four-Stroke dirt bike Pros and Cons
Pros
1. Low Noise
The structure of a four-stroke engine is completely different from the two-stroke engine. The four-stroke engine covers the combustion chamber in a water jacket to cool it, which also greatly reduces sound.
Due to the excellent structure of the engine, the noise is very less as compared to the two-stroke engine.
2. Easy to operate
A four-stroke dirt bike is smoother and easier to ride. Hence, four-stroke is more suitable for beginners. Because it is easy to handle and operate. The second big reason is that four-stroke bikes do not have much power and are not aggressive.
3. Low oil consumption
There is no doubt that a four-stroke dirt bike consumes less oil as compared to the 2 stroke bike. The four-stroke engine has a separate compartment for oil, So it is fuel-efficient and environmentally friendly.
4. Smooth Riding
The four-stroke has a wide powerband so that the bike runs smoothly and there is no jolt in increasing the speed of the bike.
Cons
1. Complex Design
The engine structure of a four-stroke is more complex than a two-stroke dirt bike. It has many separate compartments and parts.
2. Long-lasting
There is no doubt that a four-stroke dirt bike is longer-lasting than a two-stroke dirt bike. A four-stroke dirt bike lasts for about 5 to 8 years comfortably, there is no problem. But the two-stroke bike needs to be repaired every 2 or so seasons if only for regular riding.
3. Heavier
Due to the additional components, the engine of the four-stroke bike becomes heavier. Handling a four-stroke bike can be difficult for new bikers or younger ones.
| 4 Stroke Dirt Bike (by the engine) | Average Weight (lbs) | Average Weight (kg) |
| 450 cc | 249 | 113 |
| 250 cc | 239 | 108 |
| 125 cc | 196 | 89 |
The average weight of 4 stroke dirt bike
The weight of the bike depends on the bike company to company.
4. Difficult to care for and maintain
The components of a four-stroke bike are heavier and the design is more complex. So four-stroke bikes are more difficult to care for and maintain.
5. High Maintenance Cost
Four-stroke bikes have more expensive parts and accessories, and the repair cost is more than two-stroke bike parts.
6. Expensive
Generally, a four-stroke dirt bike costs more than two-stroke if we talk about the same CC engine. But the price also varies with the manufacturing company.
Conclusion:
Both the 2-stroke and our 4-stroke dirt bike have their own characteristics. Both types of bikes are great and Bikers choose them according to their convenience.
For the last few years, the 4-stroke bike has been in high demand because it is more comfortable and fuel-efficient.
But in terms of price, the 2-stroke dirt bike is more affordable.