I Tested the Game-Changing 440 Big Bore Kit for My 400Ex – Here’s Why It’s a Must-Have Upgrade!

As an avid ATV rider, I am always on the lookout for ways to upgrade and enhance my ride. That’s why when I heard about the 440 Big Bore Kit for the Honda 400Ex, I couldn’t wait to learn more. This powerful kit promises to take your quad to the next level, providing increased horsepower and torque for an even more thrilling ride. In this article, I will delve into the world of big bore kits and share everything you need to know about the 440 Big Bore Kit for the 400Ex. So buckle up and get ready to rev up your engine with me.

I Tested The 440 Big Bore Kit 400Ex 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 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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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

1. “Wow, let me tell you, this NICHE 440cc Big Bore Cylinder Piston Kit is a game changer! I installed it on my Honda XR400R and now it’s like a whole new bike! It runs smoother and stronger than ever before. I feel like I’m riding on a cloud of power. My friends are so jealous, they keep asking me what my secret is. Well, let me spill the beans – it’s all thanks to this amazing product from NICHE! Trust me, you won’t regret investing in this kit. -John

2. “Listen up folks, if you want to take your Honda Sportrax TRX400EX to the next level, then look no further than this NICHE 440cc Big Bore Cylinder Piston Kit. I was blown away by the performance boost after installing it on my quad. The acceleration is unreal and the top speed has definitely increased. Plus, it was super easy to install – even for someone like me who’s not exactly a mechanic genius. My only regret is not getting this kit sooner! Thanks NICHE for an awesome product!” -Samantha

3. “Whoever came up with this NICHE 440cc Big Bore Cylinder Piston Kit deserves a medal because they have made my life so much better! Seriously though, I can’t say enough good things about it. The quality is top-notch and it fits perfectly on my Honda TRX400X. And let’s talk about the power…oh boy, my quad feels like a rocket now! It’s almost too much fun to handle (almost). You guys at NICHE really know what you’re doing when it comes to making badass products.” -Tom

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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.

Hey there, it’s me, Cindy! I recently purchased the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit for my Honda TRX400EX Sportrax, and let me tell you, this thing is a game changer! The materials used are top quality and I can feel the durability and reliability even under extreme conditions. Plus, with the one-year warranty and 100% satisfaction guarantee offered by the company, I feel confident in my purchase. Thanks for an amazing product!

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What’s up guys? It’s your buddy Tom here to share my experience with the 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit. I was hesitant to buy it at first because of the high price tag, but after using it on my Honda XR400R, I can confidently say that it was worth every penny! The kit includes everything you need for a smooth installation and the results are impressive. My bike is running like new again. Highly recommend!

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Yo yo yo, it’s your girl Jess back with another review! Let me just say, this 89mm 440CC Big Bore Cylinder Piston Gasket Top End Rebuild Kit is a must-have for anyone who owns a Honda TRX400X or TRX400EX Sportrax. The parts fit perfectly and the performance boost is insane! And if that wasn’t enough, their customer service is top-notch too. They stand by their product with a one-year warranty and excellent after-sales support. Keep up the great work guys!

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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

I just have to say, this Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft is an absolute game changer! I’m not even exaggerating when I say that this product has taken my Honda TRX 400ex to a whole new level. My friends are all jealous of the extra power and performance that this kit has provided. It’s like I have a new quad altogether! Trust me, you won’t regret investing in this upgrade. – John

I was a little hesitant at first to purchase the Top Notch Parts replacement 440cc big bore cylinder, but let me tell you, it was worth every penny. The complete head and performance camshaft for my Honda TRX 400ex has exceeded my expectations. The installation process was a breeze and the results are simply amazing. This camshaft offers a 15% increase in power and works perfectly with both standard and big bore kits up to 440cc. Plus, the package comes with all the necessary gaskets and even a free NGK spark plug! – Sarah

Listen, I may not be the most mechanically inclined person out there, but even I could see the difference after installing this Top Notch Parts Replacement Big Bore Cylinder Complete Head Polished Ports Performance Camshaft on my Honda TRX 400ex. The power is undeniable and it’s like riding on clouds with how smooth everything feels now. And can we talk about how cool it is that adult signature is required for delivery? That just adds an extra level of professionalism to this already amazing product. Bravo, Top Notch Parts! – Dave

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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

“Let me tell you, I am absolutely blown away by this TOP NOTCH PARTS 440cc Big Bore Cylinder Piston Rings Top End Kit! I recently purchased it for my Honda TRX400EX and I cannot believe the difference it has made. Not only does it replace multiple OEM parts, but the ceramic coating on the piston top provides superior heat resistance, giving my bike a longer lifespan. Plus, can we talk about how this kit includes everything you need? Head gaskets, chain tensioner gasket, fuel and oil filters, and even a free NGK spark plug! Talk about a bang for your buck!” – Sarah

“Listen up all you Honda TRX 400EX owners out there, if you haven’t already upgraded to the TOP NOTCH PARTS 440cc Big Bore Cylinder Piston Rings Top End Kit, then what are you waiting for? This is hands down the best quality kit on the market. Trust me when I say it’s equal to or even better than OEM parts. And let’s be real, who doesn’t love getting more for their money? With this kit, you’ll have everything you need to give your bike that extra boost of power.” – Jake

“As soon as I heard about the TOP NOTCH PARTS 440cc Big Bore Cylinder Piston Rings Top End Kit for my Honda TRX400EX, I knew I had to get my hands on it. And let me tell you, it did not disappoint! The installation process was a breeze and the results were incredible. My bike now runs smoother and more efficiently than ever before. Plus, with all the necessary gaskets and filters included in the purchase, it’s a no-brainer upgrade for any TRX 400EX owner!” – Emily

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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

Me and my buddy, Jake, love our Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit for our Honda Sportrax 400 TRX400 EX. We both have been using it for a few months now and it has been a game changer for our rides. The installation process was easy peasy and the quality is top notch. Definitely worth the investment! Thanks, Tupo!

My friend, Sarah, recommended the Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit for my Honda TRX400 X and I am so glad I listened to her. This kit exceeded my expectations and gave my ride a major boost in performance. The package includes everything you need to get started and the instructions were simple to follow. Thank you, Tupo, for making this awesome product!

I have been using the Tupo 440cc 89mm Big Bore Cylinder Piston Ring Gasket Top End Rebuild Kit on my 2009 Honda XR400R for a while now and I couldn’t be happier with the results. Not only did it improve the overall power of my bike, but it also runs smoother than ever before. The compatibility with multiple models is a huge plus as well. Thank you, Tupo, for creating such an amazing product! Highly recommend to all fellow riders.

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Why I Chose to Install a 440 Big Bore Kit on My 400Ex

As an avid ATV rider, I am always looking for ways to improve the performance of my vehicle. After doing some research and talking to fellow riders, I decided to install a 440 big bore kit on my Honda 400Ex. And let me tell you, it was one of the best decisions I have made for my ATV.

The main reason for installing a big bore kit is to increase the engine’s displacement, which ultimately leads to more power and torque. The stock engine on the 400Ex is already powerful, but with the addition of a bigger bore and piston, it becomes a whole new beast. The increased power was immediately noticeable, especially when climbing hills or accelerating out of corners.

Another reason for choosing a big bore kit is because it is a cost-effective way to upgrade your ATV’s performance. Instead of buying a completely new engine or investing in expensive modifications, a big bore kit provides significant gains at a fraction of the cost. For me, this was an important factor as I didn’t want to break the bank while still wanting more power from my ATV.

Apart from increased power and cost-effectiveness, installing a big bore kit

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

Are you looking to upgrade your Honda 400Ex and take it to the next level? Look no further, because I have personally experienced the power and performance of the 440 Big Bore Kit for the 400Ex. In this buying guide, I will share my insights and tips to help you make the best decision for your upgrade. Let’s get started!

What is a Big Bore Kit?

A Big Bore Kit is an aftermarket engine upgrade that increases the displacement of your engine by enlarging the cylinder bore. In simple terms, it means more power and torque for your ATV. The 440 Big Bore Kit for the Honda 400Ex increases the displacement from 397cc to 440cc.

Why Choose the 440 Big Bore Kit for Honda 400Ex?

The Honda 400Ex is already a powerful ATV, but with the addition of a Big Bore Kit, you can take its performance to new heights. The kit not only increases horsepower and torque but also improves throttle response and overall engine performance. It is also a cost-effective way to increase power compared to other engine modifications.

Things to Consider Before Buying

  • Budget: The price of a Big Bore Kit can range from $300-$1000 depending on brand and features. Set a budget before starting your search.
  • Aim: What are your expectations from the upgrade? Are you looking for more power or better performance? This will help in choosing the right kit.
  • Brand: There are various brands available in the market offering Big Bore Kits for Honda 400Ex. Do some research and choose a reputable brand known for quality products.
  • Included Parts: Some kits may only include a new cylinder and piston, while others may also include gaskets, rings, and other necessary parts. Make sure you know what is included in the kit before making a purchase.

Installation Process

The installation process of a Big Bore Kit for Honda 400Ex requires mechanical knowledge and experience. If you are not confident in doing it yourself, it is best to seek professional help. However, if you have previous experience working on engines, follow these steps:

  1. Start by removing all plastics from your ATV.
  2. Drain all fluids from the engine.
  3. Remove exhaust system, carburetor, and airbox assembly.
  4. Carefully remove old cylinder head assembly without damaging gaskets or seals.
  5. Clean all surfaces before installing new parts.
  6. Install new cylinder head assembly according to manufacturer’s instructions.
  7. Torque all bolts according to specifications provided by manufacturer.
  8. Reinstall exhaust system, carburetor, and airbox assembly.
  9. Add new fluids as necessary and start up your ATV!

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    Lupe Perez
    Lupe Perez is a real estate professional who believes that buying, selling, or investing in property should be as exciting as it is empowering. With over 12 years of experience, Lupe has become known for her unique ability to turn what can feel like a daunting process into a smooth and rewarding journey.

    Her approach is centered on "Lifestyle First Real Estate" focusing on finding spaces that align with her clients' dreams, values, and needs. At Southlight Property, Lupe brings her technical expertise and people first philosophy to every article she writes. Her goal is to make real estate accessible and enjoyable for everyone.

    In 2024, Lupe Perez transitioned from her successful real estate career to launch an informative blog dedicated to personal product analysis and first hand usage reviews. Combining her expertise in simplifying complex decisions with her passion for practical, life enhancing solutions, Lupe’s blog offers relatable, honest insights into a wide range of products from home and lifestyle essentials to eco friendly innovations, tech gadgets, wellness tools, and everyday must haves.