Spark Plug Guide for the 2002 Harley Davidson FXDWG3
Get the right spark and keep your CVO Dyna Wide Glide's Twin Cam 88 engine firing on all cylinders.
- The OEM Harley-Davidson plug (6R12) is made by Champion, making the Champion RA8HC a direct and reliable aftermarket replacement.
- Always check and adjust the spark plug gap to between 0.038" and 0.043" before installation.
- Replacement is a very simple DIY task that takes less than 20 minutes with basic tools.
- There are no spark plug-related recalls, but a recall exists for the rear brake line on the 2002 FXDWG3 that should be checked.
Signs of Failing Spark Plugs on Your FXDWG3
Worn or fouled spark plugs can cause several noticeable problems on your Harley. Since the Twin Cam 88 engine has a plug for each cylinder, a single bad plug can make a big difference in how it runs. Watch for these common symptoms:
- Engine Misfires: You might feel a stumble, hiccup, or momentary loss of power while riding. 🎬 Watch this guide on troubleshooting a Harley engine misfire. This happens when a plug fails to ignite the fuel mixture correctly.
- Hard Starting: A weak spark makes it difficult for the engine to fire up, especially when cold. An old plug can require much more voltage to create a spark, straining your battery and starter.
- Poor Acceleration: If your bike feels sluggish or slow to respond when you twist the throttle, worn plugs could be the culprit.
- Reduced Fuel Economy: When fuel isn't burning completely because of a weak spark, you're wasting gas and your mileage will drop.
- Rough Idling: A bike that idles unevenly or stalls at stops can be a sign of a spark plug issue.
Choosing the Right Aftermarket Spark Plug
For your 2002 FXDWG3, selecting the correct spark plug is important for compatibility with the ignition system. Later model Harleys use an ion-sensing system to detect engine knock through the spark plugs, and using the wrong type can sometimes cause issues.
Brand Assessment: Champion
The original equipment Harley-Davidson 6R12 spark plug is manufactured by Champion. This makes Champion's direct aftermarket equivalent, the RA8HC, a reliable and safe choice for your bike. It is a standard copper plug designed to work correctly with your bike's ignition system. Many Harley riders and technicians stick with OEM or Champion plugs to avoid any potential electronic conflicts. While some riders have negative opinions on the brand, many others have used them for years without any problems.
Always Check the Gap
Before installing any new spark plug, you must check the gap. The correct gap for the Twin Cam 88 engine in your FXDWG3 is between 0.038 and 0.043 inches. Most mechanics set the gap to 0.040 inches as a good middle ground. Never assume a plug is gapped correctly out of the box; they can easily get bumped during shipping.
Known Issues, Recalls, or TSBs
There are no specific recalls or Technical Service Bulletins (TSBs) from Harley-Davidson or the NHTSA related to spark plugs for the 2002 FXDWG3. However, a safety recall (Campaign 0107) was issued for this specific model concerning the rear brake line, which could fracture internally and cause a loss of rear braking. It is recommended to verify if this recall service has been performed on your motorcycle.
Aftermarket vs. OEM Spark Plug Cost
| Part Type | Price Range (Per Plug) |
|---|---|
| New OEM (Harley-Davidson 6R12) | $6.99 - $11.50 |
| New Aftermarket (Champion) | $3.91 - $11.76 |
Frequently Asked Questions
How often should I change the spark plugs on my FXDWG3?
Harley-Davidson often recommends replacement every 30,000 miles or every two years. However, it's good practice to inspect them more frequently and replace them if you notice any performance issues or significant wear on the electrodes.
🎬 Doc Harley explains why regular spark plug changes are vital.Is it difficult to replace the spark plugs myself?
No, this is a very easy job for a DIY mechanic. The spark plugs on the V-twin engine are exposed and easy to access. You only need a few basic tools, like a 5/8" spark plug socket and a gapping tool.
Do I need to use anti-seize on the new spark plug threads?
Yes, applying a small amount of anti-seize compound to the new plug's threads is a good practice. It helps prevent the plug from getting stuck (seizing) in the aluminum cylinder heads, making future removal easier.
Should I replace both spark plugs at the same time?
Yes, you should always replace spark plugs as a set. This ensures even performance between both cylinders. Since they are inexpensive, it's best to change both at once.
Helpful Videos
Technical Specifications
OEM Part Numbers: 32362-04A 6R12
Engine: Twin Cam 88 Spark Plug Gap: 0.038" - 0.043" (0.97mm - 1.09mm) Socket Size: 5/8 inch Torque Spec: 12-18 ft-lbs
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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 FXDWG3: