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Spark Plug Guide for the 2004-2005 Honda TRX650FGA FourTrax Rincon GPScape

Keep your Rincon's engine firing reliably with the correct new aftermarket spark plug.

3 minutes to read 2004-2005 Honda TRX650FGA FourTrax Rincon GPScape
Difficulty
1/5
Est. Time
0.25 hrs
DIY Doable?
✅ Yes
Shop Labor
$25-$50
⚠️ Drivable, but... — Yes, but you will experience poor performance and could get stranded if the plug fails completely.
Key Takeaways
  • The recommended aftermarket spark plug is an NGK Iridium model IFR5L11, which is the same as the original equipment.
  • Symptoms of a bad plug include hard starting, rough idle, and poor acceleration.
  • Replacing the spark plug is a simple, quick, and inexpensive maintenance task you can do yourself.
  • There are no known recalls or TSBs for the spark plug on this model, but there was a recall for the steering system.
The spark plug in your Honda TRX650FGA is a small but essential part. It sits in the engine's cylinder head and creates a high-energy spark. This spark ignites the mixture of air and fuel in the engine. A strong, consistent spark is necessary for proper combustion, which powers your ATV. Without a good spark, your Rincon's engine can't run efficiently, or it may not run at all.

Signs of a Failing Spark Plug

A spark plug is a wear item, meaning it needs to be replaced as part of regular maintenance. 🎬 Follow this complete tune-up video to keep your engine running smooth. When a plug starts to fail on your Rincon, you'll notice some clear signs. Ignoring them can lead to poor performance and potentially leave you stranded on the trail.

Common Symptoms:

  • Hard Starting: The engine turns over but struggles to fire up, or won't start at all.
  • Rough Idle: The engine runs unevenly when not moving.
  • Poor Acceleration: The ATV feels sluggish or hesitant when you press the throttle.
  • 🎬 See how a struggling Rincon behaves when it's low on power.
  • Misfiring: You might hear a popping or sputtering sound from the engine, especially under load.
  • Reduced Fuel Economy: A bad plug can cause incomplete fuel combustion, making you burn more gas.

Choosing the Right Aftermarket Spark Plug

For the 2004-2005 TRX650FGA Rincon GPScape, the factory-specified plug is an NGK Iridium model, specifically the IFR5L11. This is a high-quality plug designed for long life and performance. When shopping for an aftermarket replacement, you have several options.

Brand Quality Tiers

Tier 1: OEM-Equivalent (NGK, Denso)

NGK is the original equipment manufacturer for Honda in many cases, and their IFR5L11 is the direct replacement for your Rincon. These iridium plugs offer excellent ignitability, long service life, and stable performance due to their fine-wire tip and platinum-enhanced ground electrode. Denso is another top-tier Japanese brand that offers equivalent iridium plugs. Choosing an NGK or Denso iridium plug is the safest bet for maintaining factory performance and reliability.

Tier 2: Standard Replacement (Champion)

Champion offers a range of spark plugs, including standard copper and platinum types that may be compatible. While often more affordable, these plugs typically have a shorter service life than iridium plugs. Some riders in forums note that standard plugs can be less forgiving of fouling compared to iridium or platinum types. If you choose a standard plug, be prepared to inspect and replace it more frequently.

Pro Tip: Given that the original design uses a long-life iridium plug, sticking with an aftermarket NGK or Denso Iridium IFR5L11 is highly recommended. The cost difference is minimal compared to the extended performance and reliability you get.

Cost of a New Aftermarket Spark Plug (2004-2005 Honda TRX650FGA)

Category Estimated Price Range
New Aftermarket (Iridium - NGK/Denso) $15 - $23
New Aftermarket (Standard/Copper) $3 - $8
New OEM (Honda Branded) $20 - $30

Prices are estimates and can vary based on the retailer and brand.

Frequently Asked Questions

How often should I change the spark plug on my Rincon 650?

For an iridium plug like the OEM NGK IFR5L11, a good interval is every 100-200 hours of use or every couple of years, depending on riding conditions. If you use a standard copper plug, you should inspect it annually and plan to replace it more often. Always check your owner's manual for Honda's specific recommendation.

Is changing the spark plug a difficult job?

No, this is a very easy DIY job. You will need to remove the seat to access the top of the engine. The plug is located there. You'll need a spark plug socket and a ratchet. The entire process usually takes less than 15 minutes.

🎬 Watch this step-by-step guide to changing your Rincon's spark plug.
Do I need to gap the new spark plug?

Most iridium plugs, like the NGK IFR5L11, come pre-gapped from the factory to the correct specification (0.043 inches). It is always a good practice to verify the gap with a feeler gauge, but be extremely careful not to damage the fine iridium tip. Do not use a coin-style gapper.

Are there any recalls for the spark plug on this ATV?

No, there are no specific recalls or Technical Service Bulletins (TSBs) related to the spark plug for the 2004-2005 Honda TRX650FGA. There was a recall for steering rod issues on some 2004-2005 Honda ATVs, including Rincon models, but it is unrelated to the ignition system.

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Technical Specifications

OEM Part Numbers: 30500-HN8-003 30700-HN8-003

Recommended Plug: NGK IFR5L11 or Denso VK16PRZ11. Gap: 1.0 - 1.1 mm (0.039 - 0.043 in). Socket Size: 5/8 inch.

Wrenchy
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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.

Year Coverage
This article covers the Spark Plug for:
  • Honda TRX650FGA FourTrax Rincon GPScape: 20042005
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