I think I talked to Keith during the Stafford show, isn’t that rigth?
I believe that you told me about those Champion D21 you were using and so I am now trying to find some and give it a try on my 1947 Squirrel.
The thing is that Champion D21 plugs seem to be quite hard to find in here (though I still have to check in all the agricultural machinery shops). However, Champion D16 are sold in some motorcycle shops.
By that said, as anybody tried both Champion D16 and D21? If so, what differences did you notice?