I read on here some where that the spark plug hole in the cyl. head is tapered. Meaning that the threads near the electrode have a smaller diameter then the threads near the "seat" of the plug. I was under the impression that just the "Seat" of the spark plug is tapered and where the plug contacts the head is tapered.
Does that mean that a standard 14mm x 1.25 plug re-thread tool(Tap) will do more damage then it will fix?
