Essential Spark Plug Guide for the 1999 Harley Davidson FXR2
Keep your FXR2's Evolution engine running strong with the right set of spark plugs.
- The correct OEM cross-reference for the 1999 FXR2's Evo engine is key; look for plugs replacing Harley part 5R6A.
- For best performance and easier starts, consider upgrading to NGK Iridium plugs (BPR5EIX-11).
- Standard copper plugs from Autolite (4265) or Champion (RN12YC) are a reliable, cost-effective option.
- Always check and set the spark plug gap to approximately .040 inches before installation.
Signs of Failing Spark Plugs
Worn or fouled spark plugs can't deliver the powerful spark your engine needs. When your plugs are on their way out, you'll notice a decline in performance. Look for these common symptoms on your FXR2:
- Hard Starting: The engine cranks but takes a long time to fire up, or fails to start at all.
- Rough Idle: Your bike may shake excessively or sound uneven and choppy when idling at a stoplight.
- Engine Misfires: You might feel a hesitation or stumble during acceleration and hear popping or backfiring from the exhaust.
- Poor Acceleration: The bike feels sluggish and lacks its usual snap when you twist the throttle.
- Reduced Fuel Economy: If you find yourself filling up the tank more often, failing plugs could be the cause due to inefficient fuel burn.
Choosing the Right Aftermarket Spark Plug
The original Harley-Davidson spark plug for your bike's Evolution engine is part number 5R6A. Aftermarket brands offer direct replacements that often meet or exceed OEM quality, giving you excellent options based on your budget and performance goals. Many riders prefer aftermarket plugs from brands like NGK and Autolite for their Harleys.
Good: Standard Copper Plugs
Standard copper-core plugs are a reliable and affordable choice for stock or lightly modified engines. They are excellent conductors of electricity and heat. Their main drawback is a shorter lifespan compared to more advanced materials. They are a great option if you don't mind changing your plugs more regularly as part of your maintenance routine.
- Autolite 4265: A direct cross-reference to the stock plug, known for being a solid, budget-friendly option.
- Champion RN12YC: Another popular and widely available copper plug that serves as a direct replacement for the original.
Best: Iridium Plugs
Iridium plugs are the top-tier option for performance and longevity. The iridium center electrode is extremely hard and has a very high melting point, allowing for a very fine tip. This design requires less voltage to create a spark, resulting in easier cold starts, a more stable idle, and a longer service life. Forum members frequently praise NGK Iridium plugs for their noticeable improvement in starting and overall smoothness on Evo engines.
- NGK BPR5EIX-11: This is the go-to iridium upgrade for the 1340 Evolution engine. While more expensive upfront, many owners feel the extended life and performance benefits are worth the cost.
Aftermarket Spark Plug Cost
| Tier | Brand(s) | Average Price (per plug) |
|---|---|---|
| Standard Copper | Autolite, Champion | $3.50 - $6.00 |
| Premium Iridium | NGK | $9.00 - $14.32 |
Pro Tip: Always check the spark plug gap before installation. Most Evo engines require a gap between .038 and .043 inches. Use a wire-style or feeler gauge tool. Be extra gentle if gapping an iridium plug; never use a coin-style gapper, as it can break the fine iridium tip.
Known Issues, Recalls, and TSBs
No recalls or Technical Service Bulletins (TSBs) issued by the NHTSA exist for spark plug-related issues on the 1999 Harley Davidson FXR2. Spark plug failures are almost always due to normal wear and tear over time or issues with fuel mixture or engine timing.
Frequently Asked Questions (FAQ)
How often should I change the spark plugs on my FXR2?
For standard copper plugs, a good interval is every 10,000 miles or every two years. Iridium plugs can last much longer, often up to 30,000 miles or more, but it's still good practice to inspect them during major services. Your owner's manual provides the official recommendation.
Is it necessary to use anti-seize on the plug threads?
Yes, it is highly recommended. Applying a small amount of anti-seize compound to the threads prevents the steel plug from galling or getting stuck in the aluminum cylinder heads. Some modern NGK plugs have a special plating that doesn't require anti-seize, so check the manufacturer's instructions.
Are expensive iridium plugs really worth it for an Evo engine?
Many owners say yes. The most commonly cited benefits are significantly easier and faster starts, especially in cold weather, and a smoother idle. While a standard plug provides a perfectly adequate spark, the consistency and longevity of an iridium plug is a noticeable upgrade for many riders.
Can I change the spark plugs myself?
Absolutely. Changing spark plugs is one of the easiest maintenance tasks you can perform on your Harley. It requires only basic tools like a 5/8" spark plug socket and a ratchet. It's a great way to save money and get familiar with your engine.
Technical Specifications
OEM Part Numbers: 5R6A 32342-04
Engine: Evolution 1340cc Socket Size: 5/8 inch Recommended Gap: .038" - .043" Aftermarket Cross References: - Autolite: 4265 - Champion: RN12YC - NGK Standard: BPR5ES-11 - NGK Iridium: BPR5EIX-11
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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.
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