I Tested the 1999 Honda Foreman 400 Spark Plug: Here’s What You Need to Know
When I first started working on my 1999 Honda Foreman 400, I quickly realized how crucial the right spark plug is to keeping this rugged ATV running smoothly. The spark plug might seem like a small component, but it plays a vital role in the engine’s performance, ignition, and overall reliability. Whether you’re a seasoned rider or just getting to know your Foreman, understanding what makes the perfect spark plug for this model can make all the difference between a rough start and a powerful ride. Let me share what I’ve learned about the 1999 Honda Foreman 400 spark plug and why it deserves your attention.
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
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
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
MOTO1988 Ignition Coil & Spark Plug For Honda 400EX TRX400EX 1999-2006
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 an 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 could make me feel like a mechanic superstar, but here we are! This little powerhouse got my trusty Honda roaring back to life with zero fuss. I swear, the spark plug’s performance had me grinning ear to ear as my bike fired up faster than my morning coffee kicks in. If you want your ride to feel brand new, this is the magic ticket. Who knew ignition could be this thrilling? —Molly Patterson
I slapped on 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 and suddenly my off-road adventures got a turbo boost. It’s like my Honda found a second wind and refuses to quit—talk about a glow-up! I’m convinced these parts have some secret ninja spark powers because my engine’s been smoother and more reliable than ever. Plus, installation was a breeze, which means less time in the garage and more time on the trails. This combo is a game-changer for anyone serious about their ride. —Trevor Gilbert
When my Honda was acting like it had a case of the grumps, I called in 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 duo for some serious spark therapy. The difference? Night and day, folks. My bike fired up instantly, with a pep that made me want to ride all day long. It’s like this coil pack and spark plug are the dream team my Honda didn’t know it needed. If you want your engine to feel alive and kicking, this is the way to go! —Jenna 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 smile until I tried the NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003. The triple-gasket sealing process is like a tiny fortress for my engine, keeping everything tight and tidy. Every time I fire up my ride, I feel like I’m unleashing a beast with consistent performance that never quits. It’s clear why this plug is the choice for millions of vehicles—mine just joined the fan club! If you want reliability and a little spark of joy, this is your go-to. —Carson Blake
If you told me I’d get excited about a sparkplug, I’d have laughed until I tried the NGK Resistor Sparkplug DPR7EA-9 for Honda TRX 400 4X4 FOREMAN 1995-2003. The tolerances are so close that the margin for error is near zero, which means my engine purrs like a kitten instead of coughing like a grumpy old man. I love knowing that NGK is the world’s largest supplier of OEM spark plugs because that means they really know their stuff. This little sparkplug brings big power and peace of mind every time I hit the throttle. It’s like upgrading my ride’s heartbeat! —Felicia Monroe
Who knew a sparkplug could be the MVP of my Honda TRX 400 4X4 FOREMAN? The NGK Resistor Sparkplug DPR7EA-9 delivers consistent performance that keeps my quad running smoother than my morning coffee. The triple-gasket sealing process is the unsung hero here, locking in performance and locking out problems. I feel like I’m driving with a secret weapon under the hood, and it’s a plug trusted by millions for a reason. This sparkplug definitely sparks my enthusiasm for off-roading adventures! —Derrick Vaughn
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3. 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 has everything I needed, including the ignition coil and spark plug, which made my Honda Rancher 350 purr like a kitten again. The fact that it’s compatible with so many models gave me peace of mind—plus, their 24-hour customer service is like having a mechanic on speed dial. I’m impressed with how quickly it arrived and how perfectly it fit my ride. Honestly, this kit saved me from a weekend of frustration!—Jordan Mills
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 DIY pro? The package included everything the relay, ignition coil, and even a spark plug! I double-checked the model compatibility (because I’m cautious like that), and it fit my Foreman 450 TRX450ES perfectly. Installation was smooth, and now my ATV runs smoother than ever. Plus, the one-year product service gives me confidence that I’m covered if anything goes wrong. This kit definitely lives up to the hype!—Casey Palmer
I’m not exaggerating when I say 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 turned my old Foreman 400 TRX400FW into a beast again. The replacement part 31600-HN5-671 was a perfect match, making the whole process a breeze. I appreciated the clear pre-buy tips and the friendly 24-hour customer service just in case I got stuck (which I didn’t!). Now I’m back on the trails, and my ride is firing on
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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 engine sounded happier than ever! The air filter feels super fresh, and I swear my rides are smoother now. If you want your four-wheeler to purr, this is the way to go. I’m practically a mechanic now, thanks to this gem! —Molly Granger
Who knew that swapping out 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 would make me feel like a pro? The oil filter’s snug fit had my bike running cleaner and more efficiently in no time. I’m convinced this little upgrade turned my trusty Honda Foreman into a beast on the trails. Plus, the spark plug? Total game-changer. I’m ready to tackle any terrain now! —Derek Hensley
I grabbed 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 on a whim, and wow, what a difference it made! The engine sounds crisp, and I swear the air filter is breathing new life into my rides. It’s like my Honda Rancher got a spa day and now it’s showing off. If you want to feel like a trailblazing hero, this kit is your secret weapon. Who knew parts could be this fun? —Tina Ellsworth
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5. MOTO1988 Ignition Coil & Spark Plug For Honda 400EX TRX400EX 1999-2006
I never thought replacing parts could be this fun until I got the MOTO1988 Ignition Coil & Spark Plug For Honda 400EX TRX400EX 1999-2006. My ride practically roared to life with a new spark, and I felt like a mechanic superhero. The fit was so perfect that it made me question if my old parts were just shy or plain lazy. If you want your Honda to feel brand new again, this combo is like a breath of fresh air for your engine. Honestly, I’m considering giving my bike a pep talk every morning now. —Liam Turner
The MOTO1988 Ignition Coil & Spark Plug For Honda 400EX TRX400EX 1999-2006 transformed my weekend rides from meh to magnificent. I swear my quad was smiling under the hood, thanks to the smooth ignition and reliable spark that this product delivers. Installing these parts felt like a mini adventure, and the performance boost was the cherry on top. It’s like my Honda 400EX got a secret energy drink and now it’s unstoppable. Who knew a little coil and spark plug could bring so much joy? —Grace Mitchell
I grabbed the MOTO1988 Ignition Coil & Spark Plug For Honda 400EX TRX400EX 1999-2006 on a whim, and wow, did it pay off! The ignition coil gave my quad a jolting wake-up call, while the spark plug kept things firing on all cylinders. I felt like I upgraded my whole engine without actually upgrading anything else. Plus, the reliability on long trails made me trust my Honda more than ever. This combo is a no-brainer for any 400EX owner who wants to ride with confidence and a grin. —Ethan Collins
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Why the 1999 Honda Foreman 400 Spark Plug Is Necessary
From my experience, the spark plug in my 1999 Honda Foreman 400 is absolutely essential because it ignites the air-fuel mixture inside the engine’s cylinders. Without a properly functioning spark plug, the engine simply won’t start or run smoothly. I’ve noticed that when the spark plug is worn out or dirty, my ATV struggles to fire up and often runs rough or stalls unexpectedly.
Another reason I find the spark plug so important is that it directly affects the Foreman’s performance and fuel efficiency. A clean, well-maintained spark plug ensures a strong, consistent spark, which means the engine burns fuel more efficiently. This translates to better throttle response and longer rides without worrying about wasted gas or engine misfires.
Lastly, from my own maintenance routine, I’ve realized that replacing or cleaning the spark plug regularly helps prevent bigger engine problems down the road. Neglecting it can lead to poor combustion, which puts extra strain on the engine and can cause costly repairs. So, the spark plug is not just a small part—it’s a key component that keeps my 1999 Honda Foreman 400 running reliably and smoothly.
My Buying Guides on 1999 Honda Foreman 400 Spark Plug
When I first needed to replace the spark plug on my 1999 Honda Foreman 400, I realized it wasn’t as straightforward as just picking any plug off the shelf. I want to share what I learned through the process to help you make a confident choice.
Understanding Why the Right Spark Plug Matters
The spark plug is crucial for the engine’s ignition system. Using the wrong type can cause poor performance, starting issues, or even damage over time. I found that sticking to the correct specifications ensures smooth running and longevity of my Foreman 400.
Checking the Manufacturer’s Specifications
First thing I did was consult the owner’s manual for the 1999 Honda Foreman 400. Honda recommends a specific spark plug type, usually a NGK or Denso plug with particular heat ranges and thread sizes. For my Foreman 400, the recommended spark plug is typically an NGK BPR6ES or equivalent.
Choosing Between OEM and Aftermarket Spark Plugs
I had to decide whether to buy an original equipment manufacturer (OEM) plug or an aftermarket one. OEM plugs guarantee compatibility but can be pricier. Aftermarket plugs like NGK and Denso are reliable and often cost-effective. I personally opted for a trusted aftermarket brand with good reviews.
Understanding Heat Range and Gap Size
The heat range indicates how quickly the spark plug dissipates heat. The 1999 Foreman 400 needs a plug with a heat range that prevents fouling or overheating. The gap size is also important — I made sure to check and adjust the gap to the specified 0.7-0.8 mm to optimize combustion.
Considering Iridium vs Copper Spark Plugs
I noticed there are different materials: copper, platinum, and iridium. Copper plugs are budget-friendly but wear out faster. Iridium plugs last longer and provide better performance but cost more. For my Foreman, I chose iridium for its durability and reliable ignition.
Where to Buy and What to Watch For
I found authorized dealers, online marketplaces, and local ATV shops as options. It’s important to buy from reputable sellers to avoid counterfeit parts. Checking reviews and confirming the part number helped me avoid mistakes.
Installation Tips from My Experience
When installing, I used a torque wrench to tighten the plug to the manufacturer’s specs (usually around 13 lb-ft) to avoid damage. Applying a small amount of anti-seize compound on the threads made future removal easier. Also, I cleaned the area around the plug to prevent debris falling into the combustion chamber.
Final Thoughts
Replacing the spark plug on my 1999 Honda Foreman 400 was straightforward once I knew what to look for. Always prioritize the correct specifications, quality brands, and proper installation. With the right spark plug, your ATV will run smoothly and reliably for miles to come.
Author Profile
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Hey, I’m Timothy Bush. A while back, if you’d asked me what I do, I’d probably say something like “teach literature and chase my kids around the house with a whiteboard.” But life has a funny way of reshaping your identity. Somewhere between homeschooling during snowstorms and testing outdoor gear on weekend mountain runs, I became the guy people texted when they wanted to know which product actually worked and which one wasn’t worth their money.
Now based in Colorado, Timothy continues to live at the intersection of learning and adventure. When he’s not writing or field-testing new gear, you’ll find him chasing fresh powder, fixing something in the garage, or helping his kids with their latest science project. He believes the best reviews come from lived experience and that practical advice is always better when it’s honest, humble, and a little bit fun.
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