Honda 300EX Big Bore Kit 390

Honda 300EX Big Bore Kit 390

The full potential of your off-road excursions with the Honda 300EX Big Bore Kit 390. Elevate your ride with increased power and speed, transforming your adventure into an adrenaline-fueled thrill. Specifically, the Honda 300EX Big Bore Kit 390 significantly increases horsepower and torque, providing a thrilling ride for any off-road enthusiast. In this article, we’ll dive into the benefits of upgrading to a Honda 300EX Big Bore Kit 390 and everything you need to know before upgrading.

The Honda 300EX is a popular sport ATV model with a reputation for being reliable and long-lasting. That said, many off-road riders yearn for more power and speed from their machine. This is where the Honda 300EX Big Bore Kit 390 comes in. By increasing the size of your engine, you’ll experience a whole new level of performance from your ATV. Plus, it’s a fun and rewarding DIY project for any enthusiastic rider.

What is a Big Bore Kit?

Honda 300EX Big Bore Kit 390

Before we dive too deep, let’s explain what a big bore kit is. Essentially, it’s a modification to your engine that increases the size of your cylinder and piston. This results in a greater displacement, allowing more fuel and air to be used during combustion. This, in turn, leads to an increase in power and performance. 

Power and Performance Boost

The biggest advantage of upgrading to a Honda 300EX Big Bore Kit 390 is increased horsepower and torque. The stock engine of a Honda 300EX offers around 17 horsepower. With the addition of a big bore kit, You ought to anticipate a notable increase., reaching around 30 horsepower. It also provides a torque boost you’ll feel when navigating rocky terrains. 

Greater Speed

With increased power and torque, it’s no surprise that upgrading to a Honda 300EX Big Bore Kit 390 also results in greater speed. With a larger engine, you’ll have more power to easily push through the sand, rocks, and mud. If speed is what you’re after, this kit will certainly deliver.

Engine Longevity

One of the most important aspects of upgrading to a Honda 300EX Big Bore Kit 390 is ensuring that it doesn’t hurt your engine’s longevity. This is a real concern regarding engine modifications, but when done correctly, a big bore kit can improve longevity. The increase in size reduces the overall workload for your engine, making it run cooler and smoother.

Do It Yourself

If you’re a successful DIY’er, you can easily upgrade your Honda 300EX engine with a big bore kit. However, we recommend heading to an expert if you need more confidence. Installing the kit is relatively straightforward, providing a fun and satisfying project, which can be a great way to bond with your ATV. It also satisfies you, knowing you have assembled the machine to take you on unforgettable off-road adventures.

Benefits of the Honda 300EX Big Bore Kit 390

The biggest advantage of a big bore kit is that it increases your engine’s displacement. This translates into more power, speed, and torque. In the case of the Honda 300EX big bore kit 390, you can expect a significant improvement in torque and horsepower, throttle response, and acceleration. This makes it an ideal upgrade for riders who want to take their Honda 300EX to the next level.

Drawbacks of the Honda 300EX Big Bore Kit 390

One of the biggest drawbacks of a big bore kit is that it puts more strain on your engine and can lead to increased wear and tear. This is especially true if you don’t upgrade other components of your ATV, such as the clutch, exhaust, and carburetor. Another potential drawback is that the big bore kit can make your ATV louder, which might be better if you plan on riding in areas with noise restrictions.

Installation Process 

Installing a big bore kit is a complex task and requires some technical know-how. If you need more confidence in your abilities, bringing your ATV to an experienced mechanic or shop for installation is best. However, if you’re up for the challenge, here are the basic steps for installing the Honda 300EX big bore kit 390:

Remove the old cylinder head and piston.

Assemble the new cylinder head and piston according to the manufacturer’s instructions.

Install the new cylinder head and piston into your engine

Reattach all other components and make sure everything is properly secured and tightened

Test your ATV to make sure everything is working properly before riding it

Recommended Upgrades 

As mentioned earlier, installing a big bore kit can increase the strain on other components of your ATV. Therefore, upgrading certain parts is recommended to ensure optimal performance, longevity, and safety. Some recommended upgrades for the Honda 300EX big bore kit 390 include:

Performance exhaust 

A high-flow exhaust system can improve power and reduce backpressure, which can help your engine breathe better.

High-performance carburetor

The stock carburetor might need help to keep up with the big bore kit’s increased airflow and fuel demand. Upgrading to a high-performance carburetor can improve throttle response and overall performance.

Heavy-duty clutch

A stronger clutch can handle your engine’s increased power and torque and prevent slippage.

Upgraded air filter

A high-performance air filter can provide improved airflow and filtration, which can help prevent engine damage and improve performance.

In conclusion, a big bore kit is your go-to solution if you are an off-road enthusiast seeking a power boost from your Honda 300EX. It’s a cost-effective and easy way to increase your horsepower, torque, and speed without replacing your entire engine.

The Honda 300EX Big Bore Kit 390 will transform your ATV into a high-performance machine you can be proud of. Just make sure that the installation is done correctly. We hope this article has provided valuable information on upgrading to a Honda 300EX Big Bore Kit 390 and inspires you to take your ATV experience to the next level.


What kind of engine does a Honda TRX 300X have?

An air-cooled, four-stroke, 282cc single-cylinder engine powers the Honda TRX 300EX. The piston’s stroke is 2.6 inches long, and The diameter of the cylinder bore is 2.9 inches. A 1.3-inch-diameter, piston-valve carburetor with an accelerator pump is used in the induction system. An ignition system based on capacitor discharge is present in the TRX 300EX.

Is a Honda 300X a good car?

If yes, your choices are limited, but your local Honda dealer might be the greatest option available. When the 300EX was introduced in 1993, it became an immediate hit and frequently won the title. “Best Sport 4-Stroke”.

How much gasoline does the new Honda XRE 300 use?

Thus, the average consumption in the city and the highway is 24.2 liters of gasoline per kilometer wheeled. This number can be changed with the official launch and future new New Honda XRE 300 2023 engine changes.

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