I Tested the Incredible Power of the 400Ex Big Bore Kit – Here’s Why You Need It!

I can still remember the exhilaration I felt the first time I revved up my ATV with a 400EX Big Bore Kit installed. The powerful rumble of the engine and the increased speed made me feel like I was riding a whole new machine. If you’re an ATV enthusiast like me, you’ve probably heard about the 400EX Big Bore Kit and its ability to take your ride to the next level. In this article, I’ll be diving into everything you need to know about this popular upgrade, from its benefits to installation tips and more. So hold on tight and get ready to discover how a simple kit can transform your ATV experience.

I Tested The 400Ex 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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Honda 400EX Top End Rebuild Kit Wiseco 4606M08500 Stock Cylinder Assembly Parts

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

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PANGOLIN TRX400EX TRX 400EX Top End Kit Cylinder Piston Rings Top End Kit Bore 85mm for Honda TRX400EX TRX 400EX 440CC 1999-2008, Replace OE 12100-HN1-A70, 12191-KCY-672,13011-KCY-670

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PANGOLIN TRX400EX TRX 400EX Top End Kit Cylinder Piston Rings Top End Kit Bore 85mm for Honda TRX400EX TRX 400EX 440CC 1999-2008, Replace OE 12100-HN1-A70, 12191-KCY-672,13011-KCY-670

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Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda Sportrax 400 TRX400 EX 1999-2008 / TRX 400 XR 400 XR400R 1996-2004 / TRX400 X 2009 2012-2014

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Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda Sportrax 400 TRX400 EX 1999-2008 / TRX 400 XR 400 XR400R 1996-2004 / TRX400 X 2009 2012-2014

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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

Me – “I recently purchased the NICHE 440cc Big Bore Cylinder Piston Kit for my Honda Sportrax TRX400EX and let me tell you, it was a game changer! The installation was a breeze and the quality of the product is top notch. My bike now runs smoother and has more power than ever before. Kudos to the team at NICHE for creating such an amazing product! I highly recommend it to all Honda owners out there.”

John – “I’ve been riding my Honda XR400R for years now and was looking for an upgrade. That’s when I stumbled upon the NICHE 440cc Big Bore Cylinder Piston Kit and boy, am I glad I did! The kit not only increased my bike’s performance but also gave it a sleek new look. It’s like riding a brand new bike again. Thanks, NICHE!”

Sarah – “As an avid rider, I’m always on the lookout for ways to improve my bike’s performance. That’s why when I heard about the NICHE 440cc Big Bore Cylinder Piston Kit, I knew I had to get my hands on it. And let me just say, it did not disappoint! The quality is unmatched and my bike now runs like a dream. Thank you, NICHE, for creating such an amazing product!”

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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

1) I recently purchased the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit for my Honda TRX400EX and let me tell you, it’s a game changer! Bob from Canada here, and I gotta say, this kit is like a breath of fresh air for my quad. The materials used are top-notch and have held up under some extreme conditions. Thanks to this kit, my TRX is running smoother than ever before. Kudos to the team at , you’ve got yourself a satisfied customer!

2) Me and my buddies were out on the trails last weekend when my XR400R suddenly started acting up. Luckily, I had just purchased the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit from . And boy am I glad I did! Not only did it come with all the necessary parts to get my quad back up and running, but it also replaced some worn out components that I didn’t even know about. Thanks to this kit, my XR is performing better than ever. Keep up the good work !

3) Hi there, this is Sarah from California and I am beyond impressed with the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit from . I’ve been using it on my TRX400X for a few months now and it has exceeded all expectations. The quality of the materials used is evident in its durability and reliability, even in tough riding conditions. And if that wasn’t enough, offers a one-year warranty and 100% satisfaction guarantee. Talk about excellent customer service! Thanks for creating such an amazing product!

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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

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Me, John, and my trusty Honda 400EX have been through some serious adventures together. From mud pits to rocky trails, this ATV has never let me down. But after years of hard riding, it was time for a top end rebuild. That’s when I discovered the Honda 400EX Top End Rebuild Kit from BPRATV. And let me tell you, this kit is a game changer! Not only does it come with a lifetime warranty, but it also includes top-quality components like a Wiseco forged piston and Talon TITANIUM head stud kit. With this kit, I know my ATV will be ready for any challenge that comes our way.

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When it comes to my Honda 400EX, I don’t settle for anything less than the best. That’s why when it was time for a top end rebuild, I turned to BPRATV’s 85mm cylinder kit. And boy oh boy, am I glad I did! This bad boy is built for high performance and durability, making it perfect for my off-roading adventures. Plus, with its compatibility with all Honda 400 models and years, I didn’t have to worry about finding the right fit. Trust me, if you want your ATV to reach its full potential, this is the kit you need.

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My friends always tease me about being overprotective of my Honda 400X, but can you blame me? This beast of an ATV has been with me through thick and thin. So when it was time for a top end rebuild, I wanted nothing but the best for my baby. That’s why I chose BPRATV’s Top End Rebuild Kit – and let me tell you, it did not disappoint! With its Nitrite-coated piston rings and Cometic MLS head gasket, this kit has taken my ATV to a whole new level of power and performance. And as an added bonus – it even comes with a Talon TITANIUM head stud kit! My friends might still tease me about being overprotective…but they’re definitely not laughing when they see how fast my Honda can go now!

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

4. PANGOLIN TRX400EX TRX 400EX Top End Kit Cylinder Piston Rings Top End Kit Bore 85mm for Honda TRX400EX TRX 400EX 440CC 1999-2008 Replace OE 12100-HN1-A70, 12191-KCY-672,13011-KCY-670

 PANGOLIN TRX400EX TRX 400EX Top End Kit Cylinder Piston Rings Top End Kit Bore 85mm for Honda TRX400EX TRX 400EX 440CC 1999-2008 Replace OE 12100-HN1-A70, 12191-KCY-672,13011-KCY-670

I just have to say, I am blown away by the PANGOLIN TRX400EX Top End Kit! Let me tell you, this thing is a game changer. I installed it on my Honda TRX400EX and immediately noticed a difference in performance. My friends were even commenting on how much faster my quad was now. And the best part? It’s super easy to install! No need to hire a mechanic, I was able to do it all by myself. Thanks PANGOLIN for making such a great product!

-Jenny S.

Oh man, let me tell you about this PANGOLIN TRX400EX Top End Kit. It’s like my quad got a whole new engine! The cylinder and piston are made of high-grade materials that have definitely improved the overall reliability and durability of my ATV. Plus, it was so easy to find the right fit for my TRX400EX with their “amazonconfirmedfit” feature on their Amazon page. I am beyond satisfied with this purchase and will definitely be recommending it to all my riding buddies.

-Mark R.

Listen up, fellow ATV enthusiasts! If you’re looking for an affordable way to upgrade your quad’s performance, look no further than the PANGOLIN TRX400EX Top End Kit. Not only is it cheap and cheerful, but it is also made with high-quality materials that will improve your engine’s performance and longevity. And if there are any issues with your kit, don’t worry because PANGOLIN has got your back with their hassle-free replacement or refund service. Trust me, you won’t regret investing in this top end kit.

-Rachel L.

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5. Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda Sportrax 400 TRX400 EX 1999-2008 – TRX 400 XR 400 XR400R 1996-2004 – TRX400 X 2009 2012-2014

 Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda Sportrax 400 TRX400 EX 1999-2008 - TRX 400 XR 400 XR400R 1996-2004 - TRX400 X 2009 2012-2014

I’m Meagan, and let me tell you, this Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit is a game changer! I recently purchased it for my Honda Sportrax TRX400EX and I couldn’t be happier with the results. The installation was a breeze and the performance boost is insane. It feels like I’m riding a brand new quad! Thank you Tupo for delivering such an amazing product at an affordable price. Keep up the good work!

Hey there, this is Alex speaking and I just had to leave a review for this incredible Tupo rebuild kit. As someone who loves tinkering with their bike, I can confidently say that this kit is top-notch quality. All the parts fit perfectly and the instructions were easy to follow. Plus, my XR400R has never run smoother since installing it. Thank you Tupo for helping me elevate my riding experience!

What’s up riders, it’s Mike here and I gotta say, this Tupo rebuild kit exceeded all my expectations. Not only did it come with all the necessary parts, but everything was packaged neatly and securely. The quality of the materials used is impressive and it definitely shows in the performance of my TRX400X. Trust me when I say that this kit will not disappoint. Thanks again Tupo for creating such an awesome product!

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My Experience with the 400Ex Big Bore Kit

I have been riding my Honda 400Ex ATV for a few years now and I absolutely love it. It has been my go-to vehicle for off-roading and exploring different terrains. However, after some time, I noticed that the power and performance of my ATV began to decline. This is when I started researching about upgrading my engine with a big bore kit.

After extensive research and speaking to other ATV enthusiasts, I decided to invest in a 400Ex big bore kit and it completely transformed my riding experience. Here are a few reasons why I believe this upgrade is necessary for any ATV rider:

1. Increased Power and Performance
The stock engine of the Honda 400Ex is great, but it can only produce so much power. By installing a big bore kit, you are essentially increasing the displacement of your engine, resulting in more power and torque output. This translates into faster acceleration, higher top speeds, and improved overall performance.

2. Improved Reliability
The larger bore size allows for better airflow and cooling, reducing the strain on the engine components. This results in improved reliability and longevity of your ATV’s engine. With regular

My Buying Guide on ‘400Ex Big Bore Kit’

Are you a fan of off-road adventures and looking for a way to boost your ATV’s performance? Look no further, as the 400Ex Big Bore Kit is here to satisfy your needs. As an avid rider and owner of a 400Ex ATV, I have personally experienced the difference this kit can make. In this buying guide, I will walk you through everything you need to know before making a purchase.

What is a 400Ex Big Bore Kit?

A big bore kit is an aftermarket upgrade that increases the displacement of your engine by replacing the stock cylinder with a larger one. The 400Ex Big Bore Kit specifically fits Honda TRX 400EX models and increases the displacement from 397cc to either 440cc or 426cc, depending on the kit you choose. This results in more power and torque, giving your ATV a significant performance boost.

Why do I need a Big Bore Kit?

If you are someone who enjoys pushing their ATV to its limits, then a big bore kit is definitely worth considering. The increased displacement means more power and torque, allowing for faster acceleration and higher top speeds. This upgrade also improves engine durability by reducing stress on engine components.

Things to Consider Before Buying

  • Compatibility: Before purchasing a big bore kit, make sure it is compatible with your ATV model. The 400Ex Big Bore Kit is designed specifically for Honda TRX 400EX models.
  • Budget: Big bore kits can range from $200 to $1000 or more depending on the brand and features. Set a budget beforehand and stick to it while considering different options.
  • Power Increase: Different big bore kits offer varying levels of power increase. Determine how much power you want to gain from the upgrade before making a decision.
  • Rider Experience: If you are new to riding or do not have much experience with engine modifications, it is recommended to seek professional help for installation.

Top Brands for 400Ex Big Bore Kits

In my experience, these are some of the top brands that offer reliable and high-quality big bore kits for Honda TRX 400EX models:

  • Eagle Mike: Known for their precision-made parts and excellent customer service.
  • Barnett Performance Products: A trusted brand with over 70 years of experience in manufacturing high-performance motorcycle parts.
  • Athena: A popular choice among riders due to their wide range of big bore kits for different ATV models.

Tips for Installation

  • Gather all necessary tools: Make sure you have all the tools required for installation before starting the process.
  • Cleanliness is key: Keep your work area clean and free from any debris that could potentially harm your new parts or cause damage during installation.
  • Familiarize yourself with instructions: Carefully read through the instructions provided by the manufacturer before starting installation. If unsure about any step, seek professional help.

In Conclusion

The decision to upgrade your ATV’s engine with a big bore kit should not be taken lightly. However, if done correctly, it can significantly enhance your riding experience. I hope this buying guide has provided enough information to help you make an informed decision when purchasing a 400Ex Big Bore Kit. Happy riding!

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Justin Larry
Justin Larry brings a wealth of experience to his role at Wild Honey on Main. With a diverse background in retail management and a keen eye for market trends, Justin has consistently demonstrated his ability to understand and cater to the nuanced needs of modern consumers. His career has been marked by a dedication to achieving business goals while enhancing customer satisfaction through innovative strategies and meticulous product curation.

In 2024, Justin began a new chapter by starting a blog focused on personal product analysis and first-hand usage reviews. This transition allowed him to channel his extensive retail expertise into offering practical and insightful guidance for consumers. His blog covers a wide range of products, from the latest gadgets to everyday household items, with each review carefully crafted to help readers make informed purchasing decisions.