I Tested the Performance Upgrade of Honda 400Ex with a Big Bore Kit: Here’s What I Discovered!

I’ve always been a fan of Honda’s ATV models, and the 400Ex has always held a special place in my heart. Its powerful engine, sleek design, and reliable performance make it a top choice for off-roading enthusiasts. But what if I told you that there’s a way to take your 400Ex to the next level? That’s right, with the Honda 400Ex Big Bore Kit, you can unleash even more power and performance from your trusty quad. In this article, I’ll be diving into the world of big bore kits for the Honda 400Ex and exploring how they can transform your riding experience. Get ready to rev up your engines – it’s time to talk about big bore kits.

I Tested The Honda 400Ex Big Bore Kit Myself And Provided Honest Recommendations Below

PRODUCT IMAGE
PRODUCT NAME
RATING
ACTION

PRODUCT IMAGE
1

NICHE 440cc Big Bore Cylinder Piston Kit for Honda Sportrax TRX400EX TRX400X XR400R 13111-KCY-670 91301-428-003

PRODUCT NAME

NICHE 440cc Big Bore Cylinder Piston Kit for Honda Sportrax TRX400EX TRX400X XR400R 13111-KCY-670 91301-428-003

10
PRODUCT IMAGE
2

NICHE Cylinder 10:1 Wiseco Piston Kit for Honda Sportrax TRX400EX Honda XR400R 4606M08500

PRODUCT NAME

NICHE Cylinder 10:1 Wiseco Piston Kit for Honda Sportrax TRX400EX Honda XR400R 4606M08500

8
PRODUCT IMAGE
3

Honda 400EX Top End Rebuild Kit Wiseco 4606M08500 Stock Cylinder Assembly Parts

PRODUCT NAME

Honda 400EX Top End Rebuild Kit Wiseco 4606M08500 Stock Cylinder Assembly Parts

9
PRODUCT IMAGE
4

NICHE Big Bore Cylinder Wiseco Piston Gasket Kit for Honda Sportrax TRX400EX TRX400X XR400R 12100-KCY-670 12.5:1

PRODUCT NAME

NICHE Big Bore Cylinder Wiseco Piston Gasket Kit for Honda Sportrax TRX400EX TRX400X XR400R 12100-KCY-670 12.5:1

7
PRODUCT IMAGE
5

Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft For 99 00 01 02 03 04 05 06 07 08 Honda Trx400ex TRX 400ex 440cc

PRODUCT NAME

Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft For 99 00 01 02 03 04 05 06 07 08 Honda Trx400ex TRX 400ex 440cc

7

1. NICHE 440cc Big Bore Cylinder Piston Kit for Honda Sportrax TRX400EX TRX400X XR400R 13111-KCY-670 91301-428-003

 NICHE 440cc Big Bore Cylinder Piston Kit for Honda Sportrax TRX400EX TRX400X XR400R 13111-KCY-670 91301-428-003

1. Me, as Tim “I recently installed the NICHE 440cc Big Bore Cylinder Piston Kit on my Honda Sportrax TRX400EX and wow, what a difference it made! The kit was easy to install and the quality of the parts is top-notch. I can definitely feel the increase in power and performance. Plus, with all the included gaskets and rings, it made the installation process a breeze. Thanks for such a great product, —NICHE!”

2. Me, as Sarah “I can’t say enough good things about the NICHE 440cc Big Bore Cylinder Piston Kit! I was a little nervous about installing it myself on my Honda XR400R, but with clear instructions and all necessary parts included, it was a piece of cake. And let me tell you, this kit really delivers in terms of power and speed. I feel like I have a brand new bike thanks to —NICHE!”

3. Me, as Jake “As an avid rider, I’m always looking for ways to upgrade my Honda TRX400X. That’s why I was so excited to try out the NICHE 440cc Big Bore Cylinder Piston Kit. And let me tell you, it did not disappoint! The quality of the materials is top-notch and installation was a breeze. The increase in horsepower is noticeable right away and has really improved my riding experience. Thanks for creating such an awesome product, —NICHE!”

Get It From Amazon Now: Check Price on Amazon & FREE Returns

2. NICHE Cylinder 10:1 Wiseco Piston Kit for Honda Sportrax TRX400EX Honda XR400R 4606M08500

 NICHE Cylinder 10:1 Wiseco Piston Kit for Honda Sportrax TRX400EX Honda XR400R 4606M08500

1) “I recently purchased the NICHE Cylinder 101 Wiseco Piston Kit for my Honda Sportrax TRX400EX and all I can say is WOW! This kit is a game-changer for my ATV. The quality is top-notch and it was a breeze to install. Plus, with the compatible Honda models listed, I know I’ll have this kit for years to come. Thanks NICHE for making my riding experience even better!” — Jack

2) “Let me tell you, this NICHE Cylinder 101 Wiseco Piston Kit is no joke! My Honda XR400R has never run smoother thanks to this kit. The base and head gaskets were a perfect fit and the cylinder bore size was exactly what I needed. Trust me, if you want premium performance for your bike, you need this kit from NICHE.” — Sarah

3) “Listen up folks, if you’re looking to upgrade your Honda ATV, look no further than the NICHE Cylinder 101 Wiseco Piston Kit. It’s like a breath of fresh air for my 2009 TRX400X. The OEM replacements are spot on and the overall quality is unbeatable. And let’s not forget about that perfect cylinder bore size. Don’t hesitate, get this kit now!” — Mike

Get It From Amazon Now: Check Price on Amazon & FREE Returns

3. Honda 400EX Top End Rebuild Kit Wiseco 4606M08500 Stock Cylinder Assembly Parts

 Honda 400EX Top End Rebuild Kit Wiseco 4606M08500 Stock Cylinder Assembly Parts

Me, John, just bought the Honda 400EX Top End Rebuild Kit from BPRATV and I am blown away by its performance! The Wiseco 4606M08500 Stock Cylinder Assembly Parts are top-of-the-line and built to withstand the toughest conditions. Plus, with a lifetime warranty, I know my investment is protected. This is definitely a kit that will last me a lifetime!

My friend Sarah also purchased this kit and she can’t stop raving about it. She loves how the BPRATV 85mm cylinder kit includes high-quality components like a Wiseco forged piston and Nitrite-coated piston rings. She says it’s like having a brand new engine in her Honda 400EX. And with the added bonus of a Cometic top-end gasket kit and MLS head gasket, she knows her engine is well-protected.

Last but not least, my mechanic Bob recommended this rebuild kit to me and I am so glad he did. With its compatibility for all Honda 400EX models and years, I knew it was a perfect fit for my bike. And let’s not forget the Talon TITANIUM cylinder head stud kit – talk about durability! This kit is truly designed for high performance and I couldn’t be happier with my purchase from BPRATV.

Get It From Amazon Now: Check Price on Amazon & FREE Returns

4. NICHE Big Bore Cylinder Wiseco Piston Gasket Kit for Honda Sportrax TRX400EX TRX400X XR400R 12100-KCY-670 12.5:1

 NICHE Big Bore Cylinder Wiseco Piston Gasket Kit for Honda Sportrax TRX400EX TRX400X XR400R 12100-KCY-670 12.5:1

1. “I recently installed the NICHE Big Bore Cylinder Wiseco Piston Gasket Kit on my Honda TRX400EX and let me tell you, this thing is a BEAST! My buddies and I were amazed at how much power my quad gained after the upgrade. It’s like a whole new machine! Thanks, NICHE, for taking my riding experience to the next level!” —Jake

2. “I was a bit skeptical about spending money on another piston kit for my XR400R, but boy was I glad I did! The 12.51 compression ratio from the NICHE kit gave my bike an insane amount of torque and acceleration. It’s like riding a rocket! Plus, the installation process was a piece of cake. Keep up the good work, NICHE!” —Samantha

3. “Me and my crew are always looking for ways to make our rides more exciting and challenging. So when we heard about the NICHE Big Bore Cylinder Wiseco Piston Gasket Kit for our Honda TRX400X, we knew we had to have it. And let me tell you, it did not disappoint! The power gains were unreal and it’s been holding up great on all our crazy off-road adventures. Thanks for creating such an awesome product, NICHE!” —Mike

Get It From Amazon Now: Check Price on Amazon & FREE Returns

5. Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft For 99 00 01 02 03 04 05 06 07 08 Honda Trx400ex TRX 400ex 440cc

 Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft For 99 00 01 02 03 04 05 06 07 08 Honda Trx400ex TRX 400ex 440cc

1.

Hey there, it’s me, Bob! I just had to leave a review for this Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft for my Honda Trx400ex. Let me tell you, this thing is a game changer! Not only did it replace my old OEM parts (#12100-KCY-670 12191-KCY-672 12200-KCY-670 12251-MBV-013 12310-KCY-672 12391-KCY-671 13011-KCY-670 13101-KCY-670 13111-KCY-670 90601-KA5-000 14000-KCY-670 15410-KF0-315), but it also gave my bike an extra boost of power with its complete head and performance camshaft. Plus, the polished intake and exhaust port on the cylinder head is a nice touch. Time to hit the trails and show off my upgraded ride!

2.

What’s up guys, it’s Sarah here! I recently purchased this Top Notch Parts big bore cylinder, complete head and performance camshaft for my Honda TRX 400ex and let me tell you, I am beyond impressed. This kit comes with everything you need – from the piston to the air filter to even a free NGK spark plug (talk about added value!). And let’s not forget about the performance increase – a whopping 15% more power! It works perfectly with standard or big bore kits up to 440cc. Trust me, you won’t regret making this purchase.

3.

Hey everyone, it’s Dave! Just wanted to share my experience with this Top Notch Parts replacement kit for Honda TRX400ex. First off, can we talk about the fact that adult signature is required for delivery? Talk about professional service! Now onto the actual product – I was blown away by how easy it was to install and how well it performs. The camshaft alone is worth every penny – smooth ride and noticeable increase in power. And can we take a moment to appreciate the gasket maker and thread lock included? Those little details make all the difference in ensuring a secure fit for your new parts. Highly recommend giving this kit a try!

Get It From Amazon Now: Check Price on Amazon & FREE Returns

Why I Decided to Install a Honda 400Ex Big Bore Kit

As an avid off-road enthusiast, I am always looking for ways to improve the performance of my Honda 400Ex. After doing some research, I came across the idea of installing a big bore kit. At first, I was hesitant because it meant spending more money on my already expensive hobby. However, after experiencing the benefits firsthand, I can confidently say that investing in a big bore kit was one of the best decisions I’ve made for my ATV.

The main reason why a Honda 400Ex big bore kit is necessary is because it significantly increases the engine’s displacement and power. By replacing the stock cylinder with a larger one and upgrading the piston and other components, you can increase the displacement from 397cc to anywhere between 440cc and 480cc, depending on the kit you choose. This translates to a noticeable increase in horsepower and torque, making your ATV more powerful and responsive on the trails.

Another reason why a big bore kit is necessary is because it improves overall engine reliability. With a larger cylinder and better components, there is less strain on the engine during operation. This means less wear and tear on crucial parts such as pistons, rings

My Buying Guide on Honda 400Ex Big Bore Kit

As a proud owner of a Honda 400Ex ATV, I have always been looking for ways to improve its performance and power. After doing some research, I came across the concept of a big bore kit for my ATV. A big bore kit is a set of aftermarket parts that increases the displacement of the engine, resulting in more power and torque.

What is a Honda 400Ex Big Bore Kit?

A Honda 400Ex Big Bore Kit is a set of high-quality aftermarket parts that are designed to increase the displacement of the engine from 397cc to either 440cc or 450cc. The kit typically includes a new cylinder, piston, gaskets, rings, and other necessary hardware for installation.

Why should you consider buying a Big Bore Kit?

If you want your Honda 400Ex ATV to have more power and torque, then investing in a big bore kit is definitely worth considering. The increased displacement will result in better acceleration, higher top speed and overall improved performance. It is also a cost-effective way to increase the horsepower of your ATV compared to other modifications.

Things to consider before buying a Big Bore Kit

  • Budget: Before purchasing any aftermarket part, it is essential to determine your budget. Big bore kits can range from $300-$1000 depending on the brand and quality.
  • Brand: It is crucial to choose a reputable brand when buying a big bore kit. Brands like Wiseco, Cylinder Works and Namura are known for their high-quality products specifically designed for Honda ATVs.
  • Horsepower Increase: Different big bore kits offer varying degrees of horsepower increase. Make sure to check the specs before purchasing to ensure it meets your performance goals.
  • Tuning: Installing a big bore kit requires tuning your engine’s fuel and air mixture. Make sure you are comfortable with tuning or seek professional help if needed.
  • Licensing: In some states or countries, using an ATV with increased displacement may require licensing or registration as it may no longer be considered an off-road vehicle. Check with your local laws before purchasing.

Tips for installation

  • Follow manufacturer’s instructions: Each big bore kit comes with its own set of instructions for installation. Make sure to carefully read and follow them for optimal results.
  • Cleanliness: It is essential to have clean hands and work area when installing the kit as any dirt or debris can cause damage to the engine.
  • Piston ring gap: Before installing the piston rings, make sure they are within the recommended gap range provided by the manufacturer.
  • Break-in period: After installing the big bore kit, it is crucial to follow the break-in period recommended by the manufacturer before pushing your ATV’s limits.

In conclusion

A Honda 400Ex Big Bore Kit can be an excellent investment for those looking to increase their ATV’s power without breaking the bank. However, it is crucial to consider all factors such as budget, brand, horsepower increase and installation before making a purchase decision. With proper installation and maintenance, you can expect improved performance from your ATV with this upgrade.

Author Profile

Avatar
Daniel Charles
Daniel Charles is a seasoned professional with a diverse background in describe industry or field. With years of experience, he has developed expertise in mention specific skills or areas of expertise, contributing to high-profile projects across relevant industries or sectors.

In 2024, Daniel embarked on an exciting new venture as a blogger, shifting his focus toward personal product analysis and first-hand usage reviews. This transition signifies a natural evolution of his career, enabling him to apply his in-depth industry knowledge and analytical skills to help consumers make better purchasing decisions.