PACK OF 6 CHAMPION COPPER PLUS D14 SPARK PLUGS FOR HARLEY

The Champion Copper Plus D14 is the equivalent spark plug to H-D 4, one degree cooler than the standard D16 (H-D 3). It's designed for classic Harley-Davidson bikes and is recommended when your bike runs hotter than usual, such as on the highway, at high speeds, or in hot climates.

Technical Specifications

• Equivalent to H-D 4, one thermal range cooler than the D16 (H-D 3).
• Thread M18 x 1.5 with short reach of 1/2" (12.7 mm).
• Installs with a 24 mm spark plug wrench.
• Copper core helps dissipate heat faster from the combustion chamber.
• Ultraseal™ coated shell to minimize oxidation and ease removal over the years.

When to Use a Cooler Spark Plug

• Intensive use on highways or at high speeds.
• Bikes that consistently run at higher temperatures.
• Tuned or forced engines that tend to heat the spark plug more.

Advantages for Your Classic Harley

• Helps prevent detonation and pre-ignition under demanding conditions.
• Better thermal control of the spark plug on long rides and hot days.
• Consistent spark quality in older generation engines.

Installation and Compatibility

• Ensure your model uses the H-D 4 specification or supports this cooler range spark plug.
• Adjust the electrode gap to the manufacturer's specifications.
• Carefully tighten in older cylinder heads to avoid damaging the threads.

Champion Copper Plus for Demanding Use

If you log many highway miles or enjoy a spirited ride with your classic Harley, the D14 is the logical choice when you want a high-quality, cooler spark plug built to keep up with your pace.

750 (45")/1200 (74")/1340 (80") Side Valve (Flatheads); 36-47 Knucklehead (61/74") (OHV) models (NU)