Originally Posted by mdlee1958
Since the purpose of the porcelain is to insulate and control the amount of spark I woud say your right 2Door.
Actually, mdlee, the longer thread plug is the one I always run in 26" bikes. It is the replacement for the kit supplied plug that many of us use, the NGK-6-HS. There's no piston interference with it. And as far as that goes, the shorter thread reaches into the combustion chamber the same distance. Thanks for the reply. And I neglected to add in my earlier post that I have installed the short Autolite plug and the engine seems to like it just fine.