HD 3, standard heat range.
M18X1.5 thread.
1/2″ (12.7 mm) short reach.
Used with a 24mm spark plug socket.
This D16 (HD 3) spark plug is the standard spark plug recommended for regular driving.
For extended high-speed driving, such as highway use, a cooler range The spark plug is available as the Champion D14 (HD 4) (MCS 931601 has a copper-cored center electrode and is fitted with the patented Ultraseal™ coated housing, to help keep the plug corrosion-free for a longer period of time).
Fits:> 750(45″)/1200(74″)/1340(80″) Side Valve (Flatheads); 36-47 Knucklehead (61/74″) (OHV) models
