After keeping a little log for a year on how my champions are running in my knuck i have finally decided to quit using them , whether the D16 you buy today are old stock or not i don't know , but i do know they burn out quickly, give a weak spark or an intermittent spark which in turn makes your bike run like a pig , spending time checking over all the usual things connected with these symptoms like float level,plug leads, slipped timing ,bad points , condenser ,when all along its the brand new Champion plugs you have just screwed in that are the culprit !! without changing a thing on several occasions except the Plugs from D16 Champions to NGK AB-6 the Bike ran like a dream !!!
what plugs are you running in your knuckleheads ???