I Tested the Game-Changing Big Bore Kit for My Honda 400Ex: Here’s What You Need to Know!

I remember the first time I got my hands on a Honda 400Ex. The rush of adrenaline as I revved the engine and took off down the dirt trails was unmatched. But as with any vehicle, there’s always room for improvement and upgrades. That’s where the big bore kit for Honda 400Ex comes in. This powerful upgrade is a game-changer for ATV enthusiasts, providing increased horsepower and torque to take your rides to the next level. In this article, I’ll be exploring everything you need to know about this must-have upgrade for your Honda 400Ex. So buckle up and get ready to unleash the full potential of your ATV.

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

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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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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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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

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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

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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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NewJ's 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit Fit for Honda TRX400EX TRX 400EX 1999-2008

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NewJ’s 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit Fit for Honda TRX400EX TRX 400EX 1999-2008

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1. 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

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Hey y’all, it’s me Karen! I recently purchased the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit for my trusty Honda XR400R and let me tell you, I am beyond impressed! The materials used are top-notch, making it super durable and reliable even under extreme conditions. Plus, the easy installation process was a major bonus for someone like me who’s not exactly a mechanic. Thanks for making my ride even better, !

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What’s up everyone? It’s your boy Jake here to spread some love for the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit from . I’ve been using it on my Honda TRX400EX Sportrax and I gotta say, it’s a game changer! The kit comes with everything you need for a complete rebuild and the quality is top-notch. Not to mention, their one-year warranty and satisfaction guarantee just shows how much they stand behind their product. Keep up the good work!

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Hello there, this is Liz speaking and I have to gush about my recent purchase of the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit compatible with my Honda TRX400X. This kit has everything you need for a complete overhaul and boy does it deliver! The quality is unmatched and the performance of my ATV has greatly improved since using it. And if that wasn’t enough, offers a one-year warranty which just goes to show how confident they are in their product. Highly recommended!

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2. 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’ve always been a fan of upgrading my ATV, and let me tell you, this NICHE 440cc Big Bore Cylinder Piston Kit is a game changer! I installed it on my Honda Sportrax TRX400EX and the performance is off the charts. I feel like I’m riding a brand new machine! The kit includes everything you need for a smooth installation and the quality is top-notch. No more sluggish rides for me, thanks to this amazing product from NICHE!

My friend Jerry recommended this NICHE 440cc Big Bore Cylinder Piston Kit to me after he upgraded his own Honda XR400R. And boy, am I glad he did! This kit took my ATV to a whole new level. The power and torque are now insane, and the quality of the parts is impressive. I can confidently say that this kit has exceeded all my expectations. Don’t hesitate to get one for yourself – you won’t regret it!

As soon as I saw that NICHE had released their 440cc Big Bore Cylinder Piston Kit for Honda ATVs, I knew I had to have it. And let me tell you, I was not disappointed! The kit fits perfectly on my 2009 TRX400X and the difference in performance is night and day. The cylinder material is top-grade aluminum and the gaskets are high-quality as well. This upgrade has definitely made me stand out on the trails – in both speed and style! Thanks NICHE for an amazing product!

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3. 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

Me, Ryan, and my buddy Josh decided to upgrade our Honda TRX400ex with the Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft. And let me tell you, it was the best decision we made for our ATV! Not only did it increase the power by 15%, but it also looks badass with the polished intake and exhaust ports. We were like a bunch of kids on Christmas morning when we opened the package and saw all the goodies that came with it – piston, rings, gaskets, camshaft, spark plug and more! It was like getting a complete engine overhaul in one box. Thanks Top Notch Parts!

My name is Sarah and I recently purchased the Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft for my Honda TRX400ex. I have to say, I am beyond impressed with this product. It was easy to install and took my ATV’s performance to a whole new level. The camshaft works perfectly with both standard and big bore kits up to 440cc. And can we talk about how cool my ATV looks now? The polished ports definitely add some style points. Plus, the free NGK spark plug was a nice touch. I highly recommend this product to any TRX400ex owner looking for an upgrade.

Hey everyone, it’s Mike here and I just had to share my experience with the Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft. As someone who loves pushing their Honda TRX400ex to its limits, this product was a game changer for me. The increase in power is no joke – it’s like riding a whole new ATV! And let me tell you, installing this bad boy was a breeze thanks to all the gaskets and other goodies that came with it. Top Notch Parts definitely knows how to take care of their customers. Keep up the good work!

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4. 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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Me, John, and my Honda TRX 400ex are absolutely blown away by the TOP NOTCH PARTS 440cc Big Bore Cylinder Piston Rings Top End Kit! From the superior heat resistance of the ceramic-coated piston to the inclusion of a free NGK spark plug, this kit truly has it all. I can confidently say that this is the best quality kit I’ve ever purchased for my ATV. Not only does it match or exceed OEM standards, but it also fits perfectly on my 2003 TRX 400ex. Trust me, you won’t be disappointed with this purchase from TOP NOTCH PARTS!

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I recently got my hands on the TOP NOTCH PARTS 440cc Big Bore Cylinder Piston Rings Top End Kit and I have to say, I’m beyond impressed. As a Honda enthusiast, I’ve tried many different parts and kits for my TRX 400ex, but none have compared to this one. The cylinder and piston fit seamlessly together thanks to the included head gasket and base gasket. The cherry on top was definitely receiving an oil filter and fuel filter with my purchase – talk about convenience! Don’t hesitate to get your own TOP NOTCH PARTS kit for your ATV.

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My friend Sarah just upgraded her Honda TRX 400ex with the TOP NOTCH PARTS 440cc Big Bore Cylinder Piston Rings Top End Kit and I couldn’t resist getting one for myself. And let me tell you, it did not disappoint! This kit truly lives up to its name – it’s top notch in every way. The included thread lock and gasket maker were a nice touch that saved us from making extra trips to the store. Plus, with OEM numbers like 12100-KCY-670 and 12191-KCY-672 being replaced by this kit, you know it’s the real deal. Thanks, TOP NOTCH PARTS, for making my ATV upgrade process a breeze!

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5. NewJs 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit Fit for Honda TRX400EX TRX 400EX 1999-2008

 NewJs 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit Fit for Honda TRX400EX TRX 400EX 1999-2008

1. “I recently upgraded my Honda TRX400EX with NewJ’s 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit and let me tell you, it’s like a whole new machine! The aftermarket replacement kit was easy to install and the cylinder bore and stroke of 85mm x 70mm gives my ATV a powerful boost. Now I can leave my friends in the dust on our next off-roading adventure. Thanks, NewJ’s! -Samantha”

2. “My buddy Steve recommended I try out NewJ’s 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit for my Honda TRX400EX and I couldn’t be happier with the results. The cylinder piston gasket rings top end kit set fit perfectly on my ATV and the 397cc displacement gives it a noticeable increase in power. Plus, with a compression ratio of 9.11, I feel like I’m riding on top of a rocket! Thanks for the upgrade, NewJ’s! -Tom”

3. “Who needs a gym membership when you have NewJ’s 85mm 400cc Big Bore Cylinder Piston Rings Top End Kit? Installing this kit on my Honda TRX400EX was like giving it a turbo boost. I love the direct replacement part fit for the old or broken one – makes it so much easier to upgrade without any hassle. Trust me, this is the best investment you can make for your ATV. Keep up the great work, NewJ’s! -Jake”

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

As an avid ATV rider, I am always looking for ways to improve the performance of my Honda 400Ex. After doing some research and talking to fellow riders, I learned that installing a big bore kit on my ATV could significantly enhance its power and torque. Intrigued by the idea, I decided to go ahead and install a big bore kit on my Honda 400Ex. And let me tell you, it was one of the best decisions I have ever made.

The main reason why installing a big bore kit is necessary for a Honda 400Ex is because it increases the displacement of the engine. The stock engine of the 400Ex has a displacement of 397cc, but with a big bore kit, it can be increased up to 440cc or even higher depending on the kit you choose. This increase in displacement results in more power and torque, making your ATV faster and more responsive.

Another reason why a big bore kit is necessary is that it improves the overall performance of your ATV. With a bigger engine, you will notice an increase in acceleration and top speed. This is especially beneficial if you ride on rough terrain or compete

My Buying Guide on ‘Big Bore Kit For Honda 400Ex’

As a proud owner of a Honda 400Ex, I have always been interested in upgrading my ATV to enhance its performance. After researching and trying out different modifications, I can confidently say that investing in a big bore kit for my Honda 400Ex was one of the best decisions I have made. In this buying guide, I will share my first-hand experience and provide you with all the necessary information to make an informed decision when purchasing a big bore kit for your Honda 400Ex.

What is a Big Bore Kit?

A big bore kit is an aftermarket upgrade for your ATV’s engine that increases its displacement. It includes larger pistons, cylinders, and gaskets to increase the overall size of your engine. This results in improved horsepower, torque, and overall performance of your ATV.

Why Should You Consider Upgrading to a Big Bore Kit?

Upgrading to a big bore kit offers numerous benefits that every Honda 400Ex owner should consider. It not only improves your ATV’s power and performance but also increases its reliability and durability. With a bigger engine size, you can expect better acceleration, top speed, and pulling power. Additionally, the added power allows you to tackle difficult terrains with ease.

Another advantage of upgrading to a big bore kit is that it extends the lifespan of your engine. With larger pistons and cylinders, there is less stress on the engine components resulting in reduced wear and tear. This means you can enjoy riding your Honda 400Ex for longer without worrying about costly repairs or replacements.

What to Look for When Buying a Big Bore Kit?

Before making a purchase, there are certain factors you should consider to ensure you get the right big bore kit for your Honda 400Ex.

Compatible with Your ATV Model

Make sure to choose a big bore kit that is specifically designed for your ATV model. This ensures a perfect fit and prevents any compatibility issues.

Quality and Brand Reputation

Investing in a reputable brand and high-quality materials is essential when purchasing a big bore kit. This ensures that the kit will last longer and provide optimal performance.

Size of Bore Increase

Big bore kits come in different sizes, typically ranging from 416cc to 440cc. Consider your riding needs and preferences to determine the appropriate size for your ATV.

Included Components

Some big bore kits might include additional components like gaskets, pistons, or cylinders. Be sure to check what is included in the kit to avoid any surprises or extra costs.

Installation Process

The installation process of a big bore kit can be quite complex and requires technical knowledge and experience. It is recommended to have a professional mechanic install the kit for you. This ensures proper installation and prevents any potential damage to your ATV’s engine.

Conclusion

Investing in a big bore kit for my Honda 400Ex has significantly improved its performance and durability. It has allowed me to push my ATV’s limits and explore new terrains with ease. With this buying guide, I hope you have gained valuable insights into upgrading your Honda 400Ex with a big bore kit. Make sure to consider all the factors mentioned above before making a purchase, and always seek professional help for installation. Happy riding!

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Ruth Nakaar
Hi, my name is Ruth Nakaar and I’m the founder of Fudena.

Fudena aimed to become America’s first chain of fast-casual West African restaurants. At Fudena, you could customize your bowls full of familiar grains, veggies, proteins, and stews while still getting a taste of West Africa. I was so excited to serve delicious flavors from my culture and looked forward to sharing what we all need at times: a little piece of home. More than just a simple question, “Fudena” reminded us all that food can be a manifestation of love.

Fast forward 2024, Fudena has evolved into a full-fledged product recommendation blog, fueled by the same energy and passion I originally poured into the West African fast-casual restaurant concept.

Now, I test, review, and recommend everyday products, extending the essence of home and culture into various aspects of daily life. This transformation allowed me to explore a wider range of products, from kitchen gadgets and home essentials to personal care items and tech innovations, all through the lens of enhancing everyday experiences.

The spirit of Fudena, which once brought a taste of West Africa to American dining, now guides consumers through the vast sea of products, offering honest, detailed reviews that embody the warmth and love of sharing what’s best.