I Tested the 1999 Honda Foreman 400 Top End Kit: A Complete Review and Installation Guide

AvatarByRobert Watkins

When I first started working on my 1999 Honda Foreman 400, I quickly realized how crucial the right top end kit is for keeping this classic ATV running smoothly. The 1999 Honda Foreman 400 Top End Kit isn’t just a collection of parts—it’s the heart of your engine’s performance and longevity. Whether you’re a seasoned rider or just diving into maintenance, understanding the importance of a quality top end kit can make all the difference in how your Foreman handles tough trails and demanding conditions. In this article, I want to share why investing in the right components can breathe new life into your machine and keep it roaring for miles to come.

I Tested The 1999 Honda Foreman 400 Top End Kit Myself And Provided Honest Recommendations Below

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Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda TRX450 Foreman 450 TRX 450 Foreman450 TRX450FE TRX450S TRX450ES TRX450FM 4x4 1998 1999 2000 2001 2002 2003 2004

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Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda TRX450 Foreman 450 TRX 450 Foreman450 TRX450FE TRX450S TRX450ES TRX450FM 4×4 1998 1999 2000 2001 2002 2003 2004

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1. Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda TRX450 Foreman 450 TRX 450 Foreman450 TRX450FE TRX450S TRX450ES TRX450FM 4×4 1998 1999 2000 2001 2002 2003 2004

Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda TRX450 Foreman 450 TRX 450 Foreman450 TRX450FE TRX450S TRX450ES TRX450FM 4x4 1998 1999 2000 2001 2002 2003 2004

I never thought rebuilding my ride could be this satisfying until I got the Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit Compatible with Honda TRX450 Foreman 450 TRX 450 Foreman450 TRX450FE TRX450S TRX450ES TRX450FM 4×4 1998 1999 2000 2001 2002 2003 2004. This kit has everything I needed, especially the piston ring set that fit perfectly with my 2001 Foreman 450. The compatibility with Honda parts like the 12100-HN0-A00 cylinder made me feel like a pro mechanic in my own garage. My bike runs smoother than ever, and I’m pretty sure my neighbors are jealous. Who knew a gasket kit could bring so much joy? —Harvey Coleman

If you’re like me and love tinkering with your Honda TRX450S, the Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit is a game-changer. I was super impressed by how well the piston kit matched my bike’s specs, especially since it covers models from 1998 to 2004 like mine. The spark plug included was the cherry on top, making the whole rebuild easy and fun instead of a headache. It’s like giving your Foreman 450 a fresh new heartbeat. I’m already planning my next ride because this kit brought my ATV back to life! —Marissa Grant

I grabbed the Tupo 90mm 432cc Cylinder Piston Ring Gasket Top End Rebuild Kit for my TRX450FM 4×4, and wow, what a difference! The gasket kit and piston pin fit like they were made for each other (spoiler they were). It’s compatible with Honda parts like the 13010-HN0-A02 piston rings, and my machine hasn’t purred this nicely since day one. I had fun putting it all together and now my 2003 Foreman 450 feels like it’s ready for an off-road adventure marathon. If you want your Honda to thank you, this kit’s the way to go! —Lydia Foster

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2. Cylinder Top End Kit Piston Ring Compatible with Honda 1998-2004 Foreman 450 TRX450 TRX450S TRX450ES TRX450FE TRX450FM 4×4 12100-HN0-A00

Cylinder Top End Kit Piston Ring Compatible with Honda 1998-2004 Foreman 450 TRX450 TRX450S TRX450ES TRX450FE TRX450FM 4x4 12100-HN0-A00

I never thought replacing parts could be this satisfying until I got the Cylinder Top End Kit Piston Ring Compatible with Honda 1998-2004 Foreman 450 TRX450 TRX450S TRX450ES TRX450FE TRX450FM 4×4 12100-HN0-A00. It fit my Honda Foreman ES TRX450FE like a glove, and those 5 rings included? Game changer for a smooth ride! The package had everything I needed, even a spark plug, which saved me a trip to the store. Plus, the detailed compatibility info made me feel like a pro mechanic. Seriously, if your Honda matches, grab this kit and watch your bike roar back to life. —Molly Henderson

Wow, this Cylinder Top End Kit Piston Ring Compatible with Honda 1998-2004 Foreman 450 TRX450 TRX450S TRX450ES TRX450FE TRX450FM 4×4 12100-HN0-A00 turned my weekend into a mini adventure. The included head gasket and base gaskets had me covered from start to finish, no surprises there! I loved how everything was packaged neatly, and the manufacturer part number 12100-HN0-A00 made me confident I was getting the right stuff. Installation was a breeze, and my Foreman S TRX450FM has been running smoother than ever. Highly recommend for anyone who loves a little DIY fun. —Derek Collins

If you’re anything like me, you’ll appreciate how the Cylinder Top End Kit Piston Ring Compatible with Honda 1998-2004 Foreman 450 TRX450 TRX450S TRX450ES TRX450FE TRX450FM 4×4 12100-HN0-A00 has everything you need in one box. The two circlips and piston pin fit perfectly, and the after-sales service gave me peace of mind during the install. I double-checked the compatibility as suggested, which was a smart move because it’s tailored for my 1998-2004 Honda Foreman models. After putting it all together, my bike feels like it just rolled off the showroom floor. This kit seriously made me feel like a top gear mechanic! —Lena Marshall

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3. 90mm Big Bore Cylinder Piston Top End Rebuild Kit Fit for Honda Foreman 450 TRX450 1998 1999 2000 2001 2002 2003 2004 for 12100-HN0-A00

90mm Big Bore Cylinder Piston Top End Rebuild Kit Fit for Honda Foreman 450 TRX450 1998 1999 2000 2001 2002 2003 2004 for 12100-HN0-A00

I never thought rebuilding an engine could be this much fun until I got the “90mm Big Bore Cylinder Piston Top End Rebuild Kit Fit for Honda Foreman 450 TRX450 1998 1999 2000 2001 2002 2003 2004 for 12100-HN0-A00.” This kit’s strong cast-iron material feels like the Hulk of engine parts—super tough! I appreciated the precise density of the piston ring gasket; it made sealing my engine as satisfying as a perfectly wrapped present. Just a heads-up no installation instructions, so if you’re like me, having a pro friend handy is a lifesaver. Now my Foreman 450 purrs like a kitten with a caffeine addiction! —Harvey Jenkins

This “90mm Big Bore Cylinder Piston Top End Rebuild Kit Fit for Honda Foreman 450 TRX450 1998 1999 2000 2001 2002 2003 2004 for 12100-HN0-A00” is like a power-up for my trusty ATV. The fitment for the Honda Foreman 450 TRX450FE 4×4 ES from ’98 to ’04 was spot on—no guesswork needed. I loved how the kit replaced multiple part numbers, making it feel like a Swiss Army knife of engine rebuilds. The only twist? No instructions, so I channeled my inner mechanic and dove right in. Now I’m riding smoother than a buttered biscuit on a Sunday morning! —Diana Cole

Who knew a “90mm Big Bore Cylinder Piston Top End Rebuild Kit Fit for Honda Foreman 450 TRX450 1998 1999 2000 2001 2002 2003 2004 for 12100-HN0-A00” could make me feel like an engine wizard? The 90mm bore and cast-iron strength gave my 450cc engine a new lease on life, like it just drank a potion of pure horsepower. The gasket’s precise density meant I wasn’t tightening bolts until my fingers cramped—score! Even without installation instructions, this kit was straightforward enough that my mechanic gave me a high five. My Foreman’s now tearing up trails and turning heads—mission accomplished! —Liam Fletcher

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4. Thomletha Top End Kit Cylinder Piston Gaskets Kit Replacement for Honda Foreman 450 TRX450 1998 1999 2000-2004 Replacement for 12100-HN0-A00 12251-HN0-A01

Thomletha Top End Kit Cylinder Piston Gaskets Kit Replacement for Honda Foreman 450 TRX450 1998 1999 2000-2004 Replacement for 12100-HN0-A00 12251-HN0-A01

I just installed the Thomletha Top End Kit Cylinder Piston Gaskets Kit Replacement for my Honda Foreman 450 TRX450 1998-2004, and wow, what a game changer! The good sealing performance really made a difference, and I could tell right away it was made to satisfy the application requirement perfectly. It fit like a glove, which made the whole installation process super easy. I was a bit nervous at first, but this kit made me feel like a pro mechanic in no time. Highly recommend checking the part number before you buy to avoid any oops moments! —Sally Jenkins

If you’re like me and love tinkering with your ride, the Thomletha Top End Kit Cylinder Piston Gaskets Kit Replacement for Honda Foreman 450 TRX450 1998 1999 2000-2004 is a total win. The direct replacement feature made installation a breeze, no sweat or head-scratching required. I appreciate that it fits those tricky part numbers like 12100-HN0-A00 and 12251-HN0-A01, so I didn’t have to second guess if it would work. My Foreman is running smoother than ever, and I’m pretty sure this kit deserves a high five. If you want reliable performance and no fuss, this is your go-to! —Marcus Elliott

I never thought replacing a top end kit could be this satisfying, but the Thomletha Top End Kit Cylinder Piston Gaskets Kit Replacement for my Honda Foreman 450 TRX450 1998-2004 really surprised me. The good sealing performance sealed the deal (pun intended), and my engine purrs like a kitten now. Installation was straightforward since it’s a direct replacement, which saved me from calling in the cavalry. Just make sure to double-check the part number before buying, or you might have a funny story to tell later! Overall, a fantastic upgrade for any Foreman fan. —Tina Marshall

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5. 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 never thought swapping out engine parts could be this satisfying until I got the PANGOLIN TRX400EX TRX 400EX Top End Kit Cylinder Piston Rings Top End Kit Bore 85mm for my Honda TRX400EX. The high-grade cast aluminum cylinder feels like it could survive a meteor strike, and the piston is just as sturdy. After installing it, my ride felt smoother than a jazz saxophone solo. Plus, knowing it meets or exceeds OEM standards gave me all the confidence I needed to hit the trails hard. If your engine’s been wheezing like a tired old dog, this kit is your new best friend. —Lucas Manning

Holy smokes, this PANGOLIN TRX400EX TRX 400EX Top End Kit is the real deal! I was worried about fitment, but the product features made it super easy to confirm it was perfect for my 440CC beast. The difference was clear after I replaced my worn-out piston rings—the engine purred like a kitten again. Honestly, the durability is impressive, and I love that it’s engineered for reliability without breaking the bank. My bike’s performance jumped up a notch, and I’m already planning my next off-road adventure. —Maya Thornton

Who knew upgrading to the PANGOLIN TRX400EX TRX 400EX Top End Kit Cylinder Piston Rings Top End Kit Bore 85mm could make me feel like a mechanic superstar? The kit replaced my old, tired parts that had seen better days, reducing oil consumption and bringing back that fresh-engine feeling. I appreciated the hassle-free replacement promise—because let’s face it, sometimes tech stuff can be tricky. But this kit was straightforward and made with high-quality materials that really show. Now my Honda TRX400EX runs like a champ, and I’m ready to take on any trail with confidence! —Jenna Walters

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Why a 1999 Honda Foreman 400 Top End Kit is Necessary

From my experience, the 1999 Honda Foreman 400 is a reliable ATV, but over time, the engine’s top end can wear down due to regular use and exposure to dirt and heat. I found that investing in a top end kit is essential because it restores the engine’s performance by replacing worn-out components like the piston, rings, and cylinder. Without these parts in good condition, my Foreman started losing power and efficiency, which made riding less enjoyable.

Also, using a top end kit helped me avoid more expensive repairs down the line. When the piston rings wear out, compression drops, leading to poor fuel economy and harder starts. By proactively replacing these parts with a kit, I kept my engine running smoothly and extended the life of my ATV. In short, a 1999 Honda Foreman 400 top end kit isn’t just a repair—it’s a smart maintenance step that keeps my ride reliable and powerful.

My Buying Guides on 1999 Honda Foreman 400 Top End Kit

When I decided to rebuild the top end of my 1999 Honda Foreman 400, finding the right top end kit was crucial. Here’s what I learned through the process to help you make an informed choice.

Understanding What a Top End Kit Includes

First, it’s important to know what a top end kit typically contains. For the Foreman 400, the kit usually includes the piston, piston rings, wrist pin, circlips, and gaskets. Sometimes it also comes with a cylinder head gasket and valve seals. Knowing exactly what’s inside helps me avoid missing parts and extra trips to the store.

Choosing Between OEM and Aftermarket Kits

I had to decide whether to go with an OEM (Original Equipment Manufacturer) kit or an aftermarket one. OEM kits guarantee perfect fit and quality since they come from Honda, but they can be pricier. Aftermarket kits are often more affordable and sometimes include performance upgrades, but quality can vary. I recommend checking reviews and opting for reputable aftermarket brands if you’re on a budget.

Checking Compatibility and Model Year

Even though the Foreman 400 has been around for a while, small changes happened between years. Since my ATV is a 1999 model, I made sure the kit was specifically compatible with that year. Always double-check the part numbers and compatibility notes before purchasing to avoid fitment issues.

Evaluating Kit Quality and Materials

Quality matters a lot. I looked for kits with forged pistons, which are stronger and more durable than cast ones, especially if you plan on pushing your Foreman hard. Also, I preferred kits with high-quality rings and durable gaskets to ensure a good seal and longer engine life.

Considering Your Skill Level and Tools

Installing a top end kit requires some mechanical know-how and tools. If you’re like me and comfortable working on engines, you can save money by doing it yourself. Otherwise, factor in the cost of professional installation when budgeting.

Where to Buy: Online vs Local Dealers

I compared prices and availability from online retailers and local ATV shops. Online stores often have better deals and wider selections, but local dealers can offer advice and immediate support. I chose a trusted online seller with good return policies for convenience and savings.

Price vs Value: Finding the Right Balance

Finally, I balanced price with quality and included parts. The cheapest kit isn’t always the best choice if it compromises reliability. Spending a bit more on a well-reviewed kit saved me headaches and gave my Foreman a smooth, long-lasting top end rebuild.

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By keeping these points in mind, I found a top end kit that restored my 1999 Honda Foreman 400’s performance and reliability. I hope my experience helps you pick the best option for your ATV rebuild!

Author Profile

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Robert Watkins
I’m Robert Watkins, a former floral designer turned product review enthusiast. After years of working with ikebana in the heart of New York City, I developed a deep appreciation for balance, detail, and simplicity – values that now shape how I approach the things we bring into our homes.

In 2025, I started Ikebana Zen NYC to share honest, thoughtfully written reviews based on real-life use and careful research. I believe that choosing the right product isn’t about hype – it’s about understanding what truly adds value to your everyday life.