2017 Honda TRX500FE 4x4 ESP Spark Plug Replacement Guide
Keep your Foreman running strong by knowing when and how to choose the right new spark plug.
- The recommended standard aftermarket spark plug is the NGK BKR5E-11, which is an OEM-equivalent part.
- An NGK Iridium plug (BKR5EIX-11) is a premium upgrade for longer life but is not required for normal operation.
- Verify the spark plug gap is between 1.0-1.1 mm (0.039-0.043 in) before installation.
- Replacement is a simple DIY task that requires a 5/8" or 18mm spark plug socket and takes less than 15 minutes.
Signs of a Failing Spark Plug
A spark plug is a wear item, meaning it degrades over time. When your TRX500FE's spark plug starts to fail, you'll notice. Pay attention to these common symptoms, as they often point to a plug that's due for replacement.
- Hard Starting: The engine turns over but struggles to fire up, or won't start at all. A weak spark has trouble igniting the fuel mixture, especially when the engine is cold.
- Rough Idle: When the ATV is running but not moving, the engine sounds uneven, shakes, or sputters. This can be caused by inconsistent sparks.
- Engine Misfires: You may feel a hesitation, stumble, or loss of power during acceleration. This happens when the spark plug fails to ignite the fuel in the cylinder for a cycle.
- Reduced Power and Sluggish Performance: Your Foreman may feel less responsive and weaker than usual. Incomplete combustion from a bad spark plug robs the engine of its full power.
- Worse Fuel Economy: If you're stopping for gas more often, a faulty plug could be the culprit. An inefficient spark wastes fuel by not burning the mixture completely.
Choosing the Right Aftermarket Spark Plug
For the 2017 TRX500FE, selecting a new aftermarket spark plug is straightforward. Honda uses NGK as the original equipment (OEM) supplier, which means an aftermarket NGK plug will perform just like the one your ATV came with from the factory.
Brand Tiers
- Tier 1 (OEM Equivalent): NGK
The standard recommended plug is the NGK BKR5E-11. This is a reliable, cost-effective choice that restores original performance. It is widely available and trusted by owners and mechanics. - Tier 1 (Premium Upgrade): NGK Iridium
For owners looking for longer service life and potentially a more robust spark, the NGK Iridium IX (BKR5EIX-11) is an excellent upgrade. Iridium is a harder material than the standard nickel, so it wears down much slower. While it costs more, it can be a good investment if you want the best performance and longest interval between changes.
Pro Tip: To Gap or Not to Gap?
The correct spark plug gap for the TRX500FE is 1.0–1.1 mm (0.039–0.043 in). Most NGK plugs come pre-gapped from the factory. However, it's always a smart practice to verify the gap with a feeler gauge before installation, as they can get bumped during shipping. Be extremely careful if you need to adjust an iridium plug, as the fine center electrode is fragile.
Known Issues, Recalls, or TSBs
As of early 2026, there are no known recalls, technical service bulletins (TSBs), or widespread factory issues related to the spark plugs on the 2017 Honda TRX500FE 4x4 ESP. Problems with the spark plug are almost always due to normal wear and tear or other engine issues like a rich fuel condition causing fouling.
Cost of Replacement Spark Plugs
Replacing a spark plug is one of the most affordable maintenance tasks for your ATV. The cost difference is mainly between standard and premium plug types.
| Part Type | Price Range |
|---|---|
| New OEM (Honda-Branded NGK) | $4 - $10 |
| New Aftermarket (Standard NGK) | $5 - $8 |
| New Aftermarket (Iridium NGK) | $9 - $15 |
| Shop Labor | $40 - $80 |
Frequently Asked Questions (FAQ)
How often should I change the spark plug on my TRX500FE?
A good rule of thumb is to inspect it during every major service and replace it if it looks worn, fouled, or damaged. For a standard plug, replacement every 1-2 years or 100-200 hours of use is a good preventative measure. Iridium plugs can last significantly longer.
Is an expensive iridium spark plug worth it for my Foreman?
It can be. While not required, an iridium plug like the NGK BKR5EIX-11 provides a longer service life and is more resistant to wear. If you prefer to do less maintenance or want the most consistent spark performance, the extra cost is justified.
Do I need to use anti-seize on the new spark plug threads?
NGK states that their plugs have a special trivalent plating that functions as its own anti-seize, and that using additional anti-seize compound can lead to over-torquing. While some mechanics still use a small amount out of habit, it is not recommended by the manufacturer.
What tools do I need to change the spark plug?
You will need a ratchet, a short extension, and a 5/8" or 18mm deep spark plug socket. You may also want a feeler gauge to check the gap and a torque wrench for precise installation, though it's not strictly necessary for this job.
Technical Specifications
OEM Part Numbers: 98079-5514E
Standard Plug: NGK BKR5E-11. Iridium Plug: NGK BKR5EIX-11. Gap: 1.0-1.1 mm (0.039-0.043 in). Socket Size: 5/8" or 18mm.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Honda TRX500FE 4x4 ESP: