CHAMPION COPPER PLUS SPARK PLUG D16 H-D 3 STANDARD

The Champion Copper Plus D16 is the equivalent spark plug to H-D 3, the standard heat range recommended for classic Harleys under normal and varied use.

Technical Specifications

• Equivalent to H-D 3, standard heat range.
• Thread M18 x 1.5 with a short reach of 1/2" (12.7 mm).
• Fits with a 24 mm spark plug wrench.
• Copper core for excellent thermal management.
• Ultraseal™ coated shell to help prevent corrosion.

Recommended Use

• Mixed routes: city, back roads, and occasional highways without continuous high speeds.
• Classic Harleys in stock condition or with light modifications.
• Regular use where a balance between lifespan and performance is desired.

D16 vs D14

The D16 is the standard plug for normal use. If you do a lot of highway riding at high speeds or if the engine runs very hot, you might consider switching to a D14 (H-D 4), which is a cooler range.

Installation and Maintenance

• Ensure that the equivalence H-D 3 / D16 is correct for your model.
• Adjust the electrode gap with a gauge before installation.
• Always tighten with care, especially on older cylinder heads.
• Periodically check the spark plug color to detect a rich or lean mixture, or oil consumption.

Champion Copper Plus for Classic Harleys

The D16 is a safe bet when you want a standard, reliable, and economical spark plug to keep enjoying your classic Harley just as it was meant to be.

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