But seriously, NGK are as good as anything https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.co.uk/ulk/itm/132384225362
I had problems with ngk R plugs great spark but misfired when fitted and under compression even new plugs have experienced this with different bikes always ngk R plugs guess the resistor breaks down anyway fitted bosh plugs in my 750 found them to be really good off the top of my head cannot remember the part number should be somewhere in my 750 ss ie thread wherever that is not been updated for a couple of centuries