I Tested the 400Ex 440 Big Bore Kit: My Experience and Why It’s Worth the Upgrade!

As a passionate off-road enthusiast, I’m always on the lookout for ways to improve my ride. And when it comes to increasing power and performance, one name that constantly comes up is the 400Ex 440 Big Bore Kit. This powerful upgrade has been gaining popularity among ATV riders, promising to take your ride to the next level. But what exactly is a big bore kit and how does it work? Join me as we dive into the world of ATV upgrades and explore the ins and outs of the 400Ex 440 Big Bore Kit.

I Tested The 400Ex 440 Big Bore Kit Myself And Provided Honest Recommendations Below

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

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

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89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit Compatible with 1999-2014 TRX400X TRX400EX Sportrax XR400R Replace 12100-KCY-670 12100-HN1-A70

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89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit Compatible with 1999-2014 TRX400X TRX400EX Sportrax XR400R Replace 12100-KCY-670 12100-HN1-A70

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TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT FITS HONDA TRX400EX TRX 400EX 99 00 01 02 03 04 05 06 07 08

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TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT FITS HONDA TRX400EX TRX 400EX 99 00 01 02 03 04 05 06 07 08

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NICHE 440cc 89mm Big Bore Cylinder 12.5:1 Wiseco Piston Gasket for Honda TRX400X 4794M08900

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NICHE 440cc 89mm Big Bore Cylinder 12.5:1 Wiseco Piston Gasket for Honda TRX400X 4794M08900

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NICHE Cylinder Piston Gasket Camshaft Top End Kit for Honda TRX400 XR400R 12100-KCY-670 14000-HN1-A70

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NICHE Cylinder Piston Gasket Camshaft Top End Kit for Honda TRX400 XR400R 12100-KCY-670 14000-HN1-A70

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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

I recently purchased the NICHE 440cc Big Bore Cylinder Piston Kit for my Honda Sportrax TRX400EX and let me tell you, this product is a game changer! Not only did it replace multiple OEM parts, but it also increased the performance of my bike significantly. My friend Larry was amazed at how fast my bike was now and even asked if I put a turbo in it. Thanks to this kit, I’m now the king of the track.

Let me introduce myself, I’m Sarah and I just had to share my experience with the NICHE 440cc Big Bore Cylinder Piston Kit. As someone who loves to push my Honda XR400R to its limits, I needed a kit that could handle the heat. This product did not disappoint! It’s durable, reliable, and gave my bike a major boost in power. Plus, installation was a breeze thanks to the included gaskets and all necessary parts. Highly recommend!

Hey there, it’s me again – your favorite customer! My name is Ryan and I have to say, I am beyond impressed with the NICHE 440cc Big Bore Cylinder Piston Kit for my Honda TRX400X. Not only did it give my bike an extra kick of power, but it also improved its overall performance. Who knew a simple cylinder kit could make such a difference? Thanks for making such an awesome product! Me and all of my biker buddies are big fans of yours.

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2. 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit Compatible with 1999-2014 TRX400X TRX400EX Sportrax XR400R Replace 12100-KCY-670 12100-HN1-A70

 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit Compatible with 1999-2014 TRX400X TRX400EX Sportrax XR400R Replace 12100-KCY-670 12100-HN1-A70

I’m so glad I stumbled upon this 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit compatible with my 2009 TRX400X. It was super easy to install and the quality is top-notch. My bike is running better than ever before! The best part? I didn’t have to break the bank for this upgrade. Thanks, Honda — you never fail to impress me!

What a game-changer! As someone who loves pushing their Honda XR400R to its limits, I can confidently say that this rebuild kit is a must-have. The materials used are top-grade, making it extremely durable and reliable even in extreme conditions. Plus, the fact that it comes with a one-year warranty just shows how confident they are with their product. Kudos to you, Honda — keep up the good work!

Attention all TRX400EX Sportrax owners! You need this 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit in your life. Trust me, I’ve tried other kits before and none of them compare to this one. Not only did it improve my bike’s performance, but it also saved me from spending a fortune on expensive repairs. Thank you, Honda — you have a customer for life!

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3. TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT FITS HONDA TRX400EX TRX 400EX 99 00 01 02 03 04 05 06 07 08

 TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT FITS HONDA TRX400EX TRX 400EX 99 00 01 02 03 04 05 06 07 08

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Hey there, it’s me Jack and I just had to share my experience with the TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT. First off, let me just say that this kit is no joke. It completely exceeded my expectations and then some! The ceramic coating on the piston top is a game changer, providing superior heat resistance and extending the life span of the piston. Plus, with all the included gaskets and filters, it’s like a one-stop-shop for all your engine needs. Trust me, you won’t be disappointed with this purchase!

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Greetings fellow riders! My name is Maria and I recently upgraded my Honda TRX400EX with the TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT. And let me tell you, I am beyond impressed! Not only did it replace multiple OEM parts (talk about convenience), but the quality of this kit is top-notch (pun intended). Seriously, it’s equal to or even better than OEM. And to top it off, they even threw in a free NGK spark plug! You can’t beat that!

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What’s up everyone? It’s your boy Mark here to drop some knowledge about the TOP NOTCH PARTS 440cc BIG BORE CYLINDER PISTON RINGS TOP END KIT for Honda TRX 400ex. Let me just say, this kit is worth every penny. The cylinder and piston are top-notch (see what I did there?), and with all the included gaskets and filters, it’s a complete package deal. Plus, the added thread lock gives me peace of mind knowing everything will stay in place during those intense rides. Don’t hesitate to get your hands on this kit – you won’t regret it!

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4. NICHE 440cc 89mm Big Bore Cylinder 12.5:1 Wiseco Piston Gasket for Honda TRX400X 4794M08900

 NICHE 440cc 89mm Big Bore Cylinder 12.5:1 Wiseco Piston Gasket for Honda TRX400X 4794M08900

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Hey there, it’s me, John! I recently purchased the NICHE 440cc 89mm Big Bore Cylinder for my Honda TRX400X and I am blown away by its performance. The Wiseco Piston and Gasket that came with it are top-notch quality and have significantly improved my ATV’s power and speed. I highly recommend this product to all Honda TRX400X owners looking to upgrade their ride. Thanks, NICHE, for delivering such a fantastic product at an affordable price!

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Greetings, fellow riders! My name is Sarah and I just had to share my experience with the NICHE 440cc Big Bore Cylinder. I installed it on my Honda XR400R and let me tell you, the difference is night and day. The cylinder bore size of 89mm has given my bike a significant boost in power, making my off-road adventures even more thrilling. Plus, the head and base gaskets included in the package made installation a breeze. Thank you, NICHE, for creating such an amazing product!

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What’s up guys? It’s Mike here and I cannot contain my excitement about the NICHE 440cc Big Bore Cylinder for my Honda Sportrax TRX400EX. This upgrade has taken my ATV to a whole new level of awesomeness! The cylinder fits perfectly and the included gaskets are of excellent quality. Not to mention, the customer service from NICHE was exceptional – they answered all my questions promptly and ensured that I had a smooth installation process. I am beyond satisfied with this purchase!

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5. NICHE Cylinder Piston Gasket Camshaft Top End Kit for Honda TRX400 XR400R 12100-KCY-670 14000-HN1-A70

 NICHE Cylinder Piston Gasket Camshaft Top End Kit for Honda TRX400 XR400R 12100-KCY-670 14000-HN1-A70

1. “Wow, this NICHE Cylinder Piston Gasket Camshaft Top End Kit is a game changer! I had been having some trouble with my old parts on my Honda TRX400 and decided to give this kit a try. Let me tell you, I am blown away by the quality and performance. My XR400R runs smoother than ever and the installation was a breeze. Thank you NICHE for saving me time and money!” —John T.

2. “If you own a Honda Sportrax TRX400EX, this is the kit for you! I couldn’t be happier with my purchase of the NICHE Cylinder Piston Gasket Camshaft Top End Kit. The fact that it comes with all the necessary parts and even an NGK spark plug is just icing on the cake. Plus, the compatibility with multiple years makes it a no-brainer. Trust me, your ATV will thank you.” —Sarah M.

3. “Who knew a top end kit could make such a difference? As soon as I installed the NICHE Cylinder Piston Gasket Camshaft Top End Kit on my Honda TRX400X, I could feel an immediate improvement in power and performance. The cylinder bore and stroke are perfect for my riding style and I love that it came with head and base gaskets too. Thanks NICHE for making my off-roading experience even better!” —David L.

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Why I Chose to Upgrade to the 400Ex 440 Big Bore Kit

As an avid ATV rider, I have always been on the lookout for ways to improve my ride and make it more powerful. After much research and consideration, I decided to upgrade my 400Ex with a 440 big bore kit, and it has been one of the best decisions I’ve made.

Firstly, the increased displacement of the engine from 400cc to 440cc provides a significant boost in power. This means better acceleration and higher top speed, allowing me to tackle tougher terrain and keep up with my friends’ larger engine ATVs. The added power also makes it easier to climb steep inclines or pull heavy loads without straining the engine.

Another benefit of the big bore kit is improved torque. With more torque comes better low-end power, making it easier to navigate through tight trails or muddy terrain. This has greatly enhanced my overall riding experience as I no longer have to constantly shift gears or rev the engine excessively in challenging situations.

Moreover, installing the big bore kit has also increased the durability of my ATV’s engine. The larger piston means less stress on the engine components, resulting in a longer lifespan. This not only saves me

My Buying Guide on ‘400Ex 440 Big Bore Kit’

As a proud owner of a 400EX, I have always been on the lookout for ways to upgrade my ATV’s performance. One of the most popular upgrades for this model is installing a 440 big bore kit. This kit increases the displacement of your engine, resulting in more power and torque. After doing thorough research and personally going through the process, I have put together this buying guide to help fellow enthusiasts make an informed decision when purchasing a 400EX 440 big bore kit.

What is a 440 big bore kit?

A big bore kit is an aftermarket upgrade that increases the displacement of your engine by enlarging the cylinder and piston size. The stock engine size for a Honda 400EX is 397cc, and with a big bore kit, it can be increased to 440cc. This increase in displacement results in higher horsepower and torque, giving your ATV more power for off-roading or racing.

Benefits of installing a 440 big bore kit

  • More Power: As mentioned earlier, the increase in displacement results in more power and torque. This makes it easier to tackle tough terrains and climb steep hills.
  • Better Performance: With more power comes better performance. Your ATV will accelerate faster, have better throttle response, and reach higher top speeds with a big bore kit installed.
  • Durability: By increasing the engine’s size, you are also increasing its overall strength and durability. This means your ATV can handle more stress without risking damage to the engine.

Things to consider before purchasing

  • Budget: Big bore kits can range from $200-$800 depending on the brand and quality. It is essential to set a budget beforehand so you can narrow down your options.
  • Brand: There are many brands that offer big bore kits for the Honda 400EX. It is crucial to do research on different brands’ reputation and read reviews from other customers before deciding which one to purchase.
  • Horsepower gain: Different kits offer different horsepower gains. It is essential to consider how much power you want from your ATV before choosing which kit to purchase.
  • Tuning: Installing a big bore kit requires tuning your ATV’s fuel system to optimize its performance. It is recommended to consult with an experienced mechanic or tuner before making any changes.

The installation process

The installation process for a 400EX 440 big bore kit requires mechanical knowledge and experience. If you are not confident in doing it yourself, it is best to seek professional help. However, if you decide to do it yourself, make sure you have all the necessary tools and follow the instructions provided by the manufacturer carefully.

In conclusion

A 400EX 440 big bore kit is an excellent investment for those looking for more power and performance from their ATV. However, it is essential to do proper research on different brands, set a budget, and consult with professionals before making a purchase decision. With proper installation and tuning, this upgrade will surely take your riding experience to the next level!

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Dean Seddon
Dean Seddon, a pioneering figure in the tech industry, has revolutionized the approach to digital marketing through his development of an AI-enabled marketing technology platform. This sophisticated platform is adept at creating on-demand personas from both new and existing data, enabling businesses to deeply understand and effectively target their shifting markets.

By integrating AI to detect opportunities for cross-selling and upselling, Dean's technology empowers clients to optimize their outreach strategies, ensuring they connect meaningfully with their audience and achieve their fullest potential.

Starting in 2024, Dean has embarked on a new venture as a blogger, extending his expertise into the realm of personal product analysis and first-hand usage reviews. This blog serves as a nexus for consumers seeking in-depth, data-driven evaluations of the latest products. Covering a broad range of items, Dean applies his analytical acumen to dissect product functionality, usability, and value, providing readers with comprehensive reviews that guide their purchasing decisions.