Harley Davidson FXRT Sport Glide Spark Plug Guide (1983-1992)
Keep your Evolution engine firing on all cylinders with the right set of spark plugs.
- The Champion RN12YC is a reliable and correct standard replacement spark plug for the 1983-1992 FXRT Sport Glide.
- Always check and set the spark plug gap to approximately 0.040 inches before installation.
- Symptoms like hard starting, rough idle, and poor acceleration are strong indicators that your spark plugs may need replacement.
- Changing spark plugs is a very easy and inexpensive maintenance task you can do yourself in under 15 minutes.
Is Your FXRT Telling You It's Time for New Plugs?
A spark plug is a simple part, but it's vital to your bike's performance. As plugs wear, the gap between the electrodes widens, requiring more voltage to create a spark. This makes your ignition system work harder and can lead to noticeable problems. If you're experiencing any of the issues below, your spark plugs are one of the first things you should check.
Symptoms of Failing Spark Plugs:
- Hard Starting: The engine turns over but struggles to fire up. This is often worse in cold weather.
- Rough Idle: The engine speed is uneven or stutters when the bike is not moving.
- Engine Misfires: You might feel a hesitation, stumble, or pop during acceleration as a cylinder fails to fire correctly.
- Poor Acceleration: The bike feels sluggish and lacks its usual power when you twist the throttle.
- Decreased Fuel Economy: Worn plugs lead to an inefficient burn, meaning you'll be stopping for gas more often.
- Backfiring or Sputtering: Often caused by an incomplete burn, sometimes due to loose or fouled plugs.
Choosing the Right Aftermarket Spark Plug
For the 1983-1992 FXRT Sport Glide with the Evolution engine, you don't need to spend a fortune to get reliable performance. Aftermarket plugs from reputable brands are often just as good as, if not identical to, the original equipment. The key is choosing the correct plug for your specific engine.
Aftermarket Brand Quality Assessment
| Brand Tier | Brand(s) | Our Take |
|---|---|---|
| Standard Replacement (Good) | Champion | Champion is a classic and reliable choice for the Evolution engine. The Champion RN12YC is a standard copper plug that provides excellent performance for this application. It's a direct replacement for the original equipment plug (OEM #5R6A) and is known for its reliability and affordability. Copper plugs are a great value and work perfectly in these engines, though they may need to be replaced more frequently than premium options. |
Pro Tip: Check the Gap! Always check the spark plug gap before installation, even if the box says they are "pre-gapped." The recommended gap for the Evolution engine is typically between 0.038" and 0.043". Setting it around 0.040" is a common practice that works well. Use a proper gapping tool to avoid damaging the electrode.
Cost of New Aftermarket Spark Plugs (1983-1992 FXRT)
Spark plugs are one of the most affordable maintenance items for your motorcycle. Prices are for a single spark plug, and your FXRT requires two.
| Part | Price Range |
|---|---|
| New Aftermarket Spark Plug (Champion) | $3.50 - $9.31 |
Frequently Asked Questions
How often should I change my FXRT's spark plugs?
For standard copper plugs like the Champion RN12YC, it's good practice to inspect them annually and replace them every 10,000 miles or every two years, whichever comes first. Given their low cost, frequent replacement is cheap insurance against performance issues.
Is there a difference between OEM and aftermarket spark plugs for my bike?
For a standard part like a spark plug, there is little to no performance difference between an OEM Harley-Davidson plug and a quality aftermarket one like a Champion, which is often an OEM supplier. The Champion RN12YC is a proven, reliable plug for the Evolution engine.
Do I need special tools to change my spark plugs?
You will need a spark plug socket (typically 13/16" for these plugs), a ratchet, and an extension. A torque wrench is recommended to ensure you don't over-tighten the plugs, and a feeler gauge or gapping tool is essential for checking the gap. Applying a small amount of anti-seize to the threads is also a good practice.
Are there any recalls for the spark plugs on my FXRT?
No, there are no recalls or technical service bulletins (TSBs) from the NHTSA related to spark plugs for the 1983-1992 Harley Davidson FXRT Sport Glide. Spark plugs are considered a standard wear-and-tear maintenance item.
Technical Specifications
OEM Part Numbers: 5R6A 32311-83
Recommended Spark Plug: Champion RN12YC or equivalent. Recommended Gap: 0.038"-0.043". Socket Size: 13/16". Quantity Required: 2.
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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.
- Harley Davidson FXRT Sport Glide: