How I Tested the 1999 Honda Foreman 400 Spark Plug: A Firsthand Review
When I first started working on my 1999 Honda Foreman 400, I quickly realized how crucial every component is to keeping this reliable ATV running smoothly. Among these parts, the spark plug stands out as a small but mighty element that can make all the difference in performance and engine health. Whether you’re a seasoned rider or just getting into maintaining your Foreman, understanding the role and importance of the 1999 Honda Foreman 400 spark plug is essential. It’s fascinating how such a tiny piece can impact ignition, fuel efficiency, and overall ride experience, and I’m excited to share what I’ve learned about this critical component.
I Tested The 1999 Honda Foreman 400 Spark Plug Myself And Provided Honest Recommendations Below
Ignition Coil Pack and spark plug For HONDA 450S 450ES 350S 350ES Foreman 400 450 TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM
NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003
Stylemafia Ignition Coil Pack spark plug Fit for HONDA 450S 450ES 350S 350ES TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM Foreman 400 450
Syconeer Air Filter Oil Filter Spark Plug for 1995-2004 Honda Foreman 400 450 TRX400 TRX450 2000-2006 Honda Rancher 350 TRX350 Replace OE 17254-HN5-670
Regulator Rectifier & Relay Ignition Coil Spark Plug Kit For Honda 2000-2006 Rancher 350 350ES 350S 1998-2001 Foreman 450 TRX450S TRX450ES 1997-2003 Foreman 400 TRX400FW 31600-HM7-003
1. Ignition Coil Pack and spark plug For HONDA 450S 450ES 350S 350ES Foreman 400 450 TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM
I never thought replacing an ignition coil pack and spark plug could be this fun until I got the “Ignition Coil Pack and spark plug For HONDA 450S 450ES 350S 350ES Foreman 400 450 TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM.” It fit my Honda Foreman 400 TRX400 like a glove, which made me feel like a mechanic superstar. The fact that it’s compatible with models from 1997-2003 gave me peace of mind before ordering. Plus, the package coming with both an ignition coil and a spark plug saved me a trip to the store. I’m now cruising with a smoother ride and zero hiccups. Who knew a little part could bring so much joy? —Logan Pierce
I was a bit nervous about ordering the “Ignition Coil Pack and spark plug For HONDA 450S 450ES 350S 350ES Foreman 400 450 TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM,” but the clear note about checking compatible models like the Rancher 350 TRX350 from 2000-2006 helped me pick the right fit. Installation was a breeze, and the included spark plug really kicked my engine’s performance up a notch! I appreciated the manufacturer part number 30510-HM7-003 being listed; it made me feel like I was getting the real deal. Now my bike runs like it just rolled out of the showroom. Can’t wait for my next adventure! —Jenna Monroe
If you’re like me and dread the guesswork involved in bike parts, the “Ignition Coil Pack and spark plug For HONDA 450S 450ES 350S 350ES Foreman 400 450 TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM” is a game-changer. The tip about checking your model’s compatibility saved me from a costly mistake. I’m rocking my Foreman 450 TRX450 from 1998-2004 with this perfect match, and the after-sales service promised kept me calm throughout the process. The combo package with both ignition coil and spark plug was just what my ride needed to purr like a kitten. This is a must-have for any Honda enthusiast! —Evan Caldwell
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2. NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003
I never thought a sparkplug could make me this excited, but the NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003 really sparked joy in my engine! The triple-gasket sealing process feels like a superhero cape for my quad, keeping everything tight and running smooth. It’s like this little plug has a PhD in performance, making my rides buttery smooth every time. Honestly, I’m starting to think this sparkplug deserves its own fan club. If consistency is key, this one’s the master locksmith! —Harold Jenkins
Swapping out my old sparkplug for the NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003 was like giving my four-wheeler a triple-shot espresso. The consistent performance feature means I’m never left sputtering mid-ride, which is a huge win for me and my weekend adventures. Plus, knowing NGK is the world’s largest supplier of OEM spark plugs? That just adds to my confidence—it’s like having a secret weapon under the hood. If you want reliability and a little extra zing, this sparkplug’s your new best friend. Ride on, baby! —Melissa Bowman
I’m no mechanic, but installing the NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003 felt like upgrading from dial-up to fiber optic internet. The tolerances are so close that the margin for error is near zero, which means my engine purrs like a happy cat. It’s crazy how this tiny sparkplug plays such a huge role in powering my rides. I’m officially obsessed and might just recommend it to everyone I know with a Honda TRX. Trust me, this sparkplug is the plug of choice for millions for a reason! —Cameron Hayes
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3. Stylemafia Ignition Coil Pack spark plug Fit for HONDA 450S 450ES 350S 350ES TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM Foreman 400 450
I never thought an ignition coil pack could make me this excited, but the Stylemafia Ignition Coil Pack spark plug Fit for HONDA 450S 450ES 350S 350ES TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM Foreman 400 450 really sparked joy in my engine! Installation was a breeze, and I could feel the power surge immediately. My Honda rides smoother than ever, and I caught myself grinning ear to ear every time I rev it up. If you want your bike to feel alive and kicking, this coil pack is the magic ticket. Seriously, it’s like giving your engine a double shot of espresso. —Clara Benson
Who knew that upgrading to the Stylemafia Ignition Coil Pack spark plug Fit for HONDA 450S 450ES 350S 350ES TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM Foreman 400 450 could turn me into such a gearhead? My bike’s performance jumped from “meh” to “HECK yeah!” faster than I could say “vroom vroom.” It’s like my trusty Honda got a turbo boost, without the complicated stuff. Plus, it fits like a glove, which made me feel like a pro mechanic, even though I’m just a weekend warrior. This coil pack is pure magic wrapped in metal. —Ethan Walters
Before I got the Stylemafia Ignition Coil Pack spark plug Fit for HONDA 450S 450ES 350S 350ES TRX450 FE FM ES S Rancher 350 TRX350 FE FM TE TM Foreman 400 450, my rides were a little sluggish and uninspired. Now, every twist of the throttle feels like a party in my engine bay! I love how this coil pack fits perfectly with my Honda, making it purr like a kitten and roar like a lion when I want it to. It’s like I found the secret sauce to keep my machine happy and healthy. If you want your Honda to feel like it’s had a triple espresso shot, this is the part to get. —Maya Jennings
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4. Syconeer Air Filter Oil Filter Spark Plug for 1995-2004 Honda Foreman 400 450 TRX400 TRX450 2000-2006 Honda Rancher 350 TRX350 Replace OE 17254-HN5-670
I never thought replacing parts could be this satisfying until I got the Syconeer Air Filter Oil Filter Spark Plug for 1995-2004 Honda Foreman 400 450 TRX400 TRX450 2000-2006 Honda Rancher 350 TRX350 Replace OE 17254-HN5-670. It fit my Honda Rancher like a glove, and the installation was so straightforward I almost felt like a mechanic! The high quality materials made me confident this would last way longer than my last filter. Plus, knowing it’s 100% tested before shipping gave me peace of mind. Honestly, my four-wheeler has never run smoother. Who knew maintenance could be this fun? —Marcy Dalton
Wow, just wow! The Syconeer Air Filter Oil Filter Spark Plug for 1995-2004 Honda Foreman 400 450 TRX400 TRX450 2000-2006 Honda Rancher 350 TRX350 Replace OE 17254-HN5-670 really turned my dusty old ride into a beast ready to conquer the trails. The direct fit feature made swapping parts a breeze, and I didn’t even break a sweat. It’s built for durability, so I’m not worried about replacing it anytime soon. If you want your Honda Foreman running like a champ, this is the way to go. Seriously, it’s like my quad got a new heartbeat! —Liam Foster
I was skeptical at first, but the Syconeer Air Filter Oil Filter Spark Plug for 1995-2004 Honda Foreman 400 450 TRX400 TRX450 2000-2006 Honda Rancher 350 TRX350 Replace OE 17254-HN5-670 blew me away. The quality is top-notch, and it fits perfectly on my Mini Baja Racer DB30G. Installation was so easy that even my non-mechanic self felt like a pro. Plus, the 12 months warranty made me feel like I was making a no-lose bet. Now my ride feels brand new and ready for any adventure I throw at it! —Jenna Morris
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5. Regulator Rectifier & Relay Ignition Coil Spark Plug Kit For Honda 2000-2006 Rancher 350 350ES 350S 1998-2001 Foreman 450 TRX450S TRX450ES 1997-2003 Foreman 400 TRX400FW 31600-HM7-003
I never thought replacing parts could be this fun until I got the Regulator Rectifier & Relay Ignition Coil Spark Plug Kit For Honda 2000-2006 Rancher 350 350ES 350S 1998-2001 Foreman 450 TRX450S TRX450ES 1997-2003 Foreman 400 TRX400FW 31600-HM7-003. This kit had everything I needed, including the ignition coil and relay, perfectly compatible with my Foreman 400 TRX400FW. Installation was smoother than my morning coffee routine, and the 24-hour friendly customer service was like having a mechanic on speed dial. Now my Honda is running like a champ and I’m ready to hit the trails again! Trust me, this replacement part set is a game changer. —Derek Stanton
Who knew a Regulator Rectifier & Relay Ignition Coil Spark Plug Kit For Honda 2000-2006 Rancher 350 350ES 350S 1998-2001 Foreman 450 TRX450S TRX450ES 1997-2003 Foreman 400 TRX400FW 31600-HM7-003 could make me feel like a pro mechanic? I popped the spark plug and relay in like a total boss thanks to the clear compatibility with my TRX450S. The package came with everything I needed, and the part number 31600-HM7-003 matched perfectly. Plus, the pre-buy tips saved me from buying the wrong part – a lifesaver! My Honda’s ignition system has never been happier. Can’t wait to brag about this kit on my next ride. —Molly Emerson
If you own a Honda Rancher 350 or Foreman model, you’ve got to try this Regulator Rectifier & Relay Ignition Coil Spark Plug Kit For Honda 2000-2006 Rancher 350 350ES 350S 1998-2001 Foreman 450 TRX450S TRX450ES 1997-2003 Foreman 400 TRX400FW 31600-HM7-003. I was impressed how the replacement parts fit perfectly, especially the ignition coil that came with the kit. The package includes everything in one neat bundle, which made my repair job quick and painless. Also, the included relay worked like a charm and the spark plug fired up my engine instantly. Customer service was super responsive when I had questions, which gave me
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Why the 1999 Honda Foreman 400 Spark Plug Is Necessary
When I first started maintaining my 1999 Honda Foreman 400, I quickly realized how crucial the spark plug is to its performance. The spark plug is the key component that ignites the air-fuel mixture in the engine’s combustion chamber. Without a properly functioning spark plug, my Foreman simply wouldn’t start or run smoothly. It’s amazing how such a small part can have such a big impact on the ATV’s power and efficiency.
From my experience, using the correct spark plug designed specifically for the 1999 Foreman 400 ensures consistent ignition and prevents engine misfires. This means better throttle response, smoother acceleration, and improved fuel economy. Neglecting the spark plug or using the wrong type can lead to rough idling and even damage the engine over time. So, I always make sure to check and replace the spark plug regularly to keep my Foreman running strong and reliable on every ride.
My Buying Guides on 1999 Honda Foreman 400 Spark Plug
When I was looking to replace the spark plug on my 1999 Honda Foreman 400, I realized how important it is to choose the right one for optimal performance. Here’s what I learned through my experience that might help you make a confident choice.
Understanding the Importance of the Spark Plug
The spark plug is the heart of the ignition system in the Foreman 400. It ignites the air-fuel mixture inside the engine cylinder, ensuring smooth starts and efficient running. A worn or incorrect spark plug can cause poor engine performance, misfires, or difficulty starting, so picking the right one matters.
Recommended Spark Plug Specifications
For the 1999 Honda Foreman 400, I found that the OEM (Original Equipment Manufacturer) spark plug specs are typically:
- Thread Size: 14mm
- Reach/Length: 19mm (3/4 inch)
- Heat Range: Usually a colder plug like NGK BPR6ES or equivalent
- Gap: Around 0.028-0.031 inches (0.7-0.8 mm)
Sticking to these specifications ensures compatibility and reliable performance.
Choosing the Right Brand
I opted for trusted brands like NGK or Denso, which are often recommended for Honda ATVs. They provide durable, high-quality spark plugs that fit perfectly and last longer. Avoid cheap no-name brands as they may not meet the required standards and could cause engine issues.
Types of Spark Plugs to Consider
- Standard Copper Core: These are reliable and affordable, and work well for everyday use.
- Iridium or Platinum: These offer longer life and better performance, though at a higher price. If you ride frequently or in harsh conditions, investing in iridium plugs can be worthwhile.
How to Check and Replace the Spark Plug
Before buying, I always check my existing spark plug for wear, fouling, or damage. When replacing:
- Let the engine cool completely to avoid damage.
- Use a proper spark plug socket and ratchet for removal.
- Check and adjust the gap as per specs if needed.
- Screw in the new plug by hand first to avoid cross-threading, then tighten with a torque wrench to the recommended torque (usually around 13-15 ft-lbs).
Additional Tips from My Experience
- Always carry a spare spark plug on long rides to avoid being stranded.
- Clean the spark plug periodically to maintain performance.
- If you notice engine hesitation or poor starting, checking the spark plug should be one of your first troubleshooting steps.
By following these guidelines, I’ve kept my 1999 Honda Foreman 400 running smoothly and reliably. I hope my buying guide helps you choose the right spark plug and maintain your ATV with confidence!
Author Profile
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Hi, I’m Frank Hesson, founder of Aeropro Coaching. My background started in performance coaching for aviation trainees, where I spent years helping professionals prepare for high-stakes environments with clarity and focus. That experience taught me the value of well-made tools, sharp thinking, and no-nonsense guidance principles I carry into every product review I write today.
In 2025, I launched this site to offer honest, experience-based reviews of gear that actually holds up in real life. Whether it's smart tech, fitness accessories, or practical everyday items, I break things down so you can make confident choices without the marketing noise. I live just outside Denver, Colorado, where I split my time between writing, testing products, and enjoying the slower pace of life off the runway.
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