Then you need this also.....https://www.sparkplugs.co.uk/spark-plug-symbol-codes/Bro, another question. Does FKR and BKR really got different? From 4B11 manual state recommended spark NGK FR6EI or Denso IK20 or VK20. From the cross reference you gave earlier, IK20 = BKR6EIX-1. any different?
Thank You in advance.