Champion 671 V57YC 14mm Alky Racing Spark Plug-.46 In Reach-5/8 In Hex
SparkPlugs.com: RN4C $3.39 Champion 104 Spark Plug - Best Car SparkPlug Replacement
SparkPlugs.com: RN12YC $3.16 Champion 404 Spark Plug - Best Car SparkPlug Replacement
Champion® 404 RN12YC Copper Spark Plug for V-Twins - Replacement for OEM# 5R6A on 1984-2000 Evolution and 1975-1980 Shovelhead (1200cc) Harley Motors - MADE IN USA - Billet Proof Designs
Champion Copper Plus Spark Plug - RN12YC Harley Motorcycle - Dennis Kirk
Champion® 810 RA8HC Copper Plus Spark Plug for V-Twins - Replacement for OEM# 6R12 - Fits 1986-Up Sportster (XL) and 1999-2017 Twin Cam Harley Models and All 1988-2008 Buell Models - MADE