Basic question I know but which spark plug is best for a 1969 A50 Royal Star. I need to order some asap but don't have the info to hand.
Many thanks.
Just to add - I wondered if champion or ngk were preferred.
I tend to stick with Champion on British Bikes , N4 for my 1969 A50 Royal Star.
NGK I leave for the others apart from the Harleys.
I would recommend Brisk spark plugs. Champion and NGK dont glaze the insulator as (apparently?) no need to with modern day unleaded fuels injected into the cylinder. Misfires can crack such insulators and sparks short across.
Call Dave Angel at Brisk (F2 motorcycles, Wisbech) and he will explain everything and recommend the correct plug.