H-D #4, one range colder. M18 X 1.5 threaded. 1/2" (12.7mm) short reach. Used with 24mm spark plug socket. This D14 (H-D #4) is one range colder (runs less hot/removes heat faster) than the standard D16 (H-D #3) spark plug.
Champion Copper Plus Spark Plugs (4) RG6HCC (6R10) fits Harley Milwaukee Eight
Champion Copper Plus Spark Plugs (2) RA8HC, 6R12 fits Harley Twin Cam/Sportster
GENUINE CHAMPION SPARK PLUG - CJ8-(NGK BM6A)-COPPER PLUS
Pair of L82C Champion Copper Plus Spark Plugs Triumph BSA
Pair of N5C Champion Copper Plus Spark Plugs Triumph BSA
BSA BANTAM D1 D3 D5 D7 D10 D14 B175 T20 GENUINE CHAMPION SPARK PLUG CAP 'NEW'