Normal!
Normal!
you cant get anything more normal than a 14mm spark plug
The first time I even saw anything different was in the late sixties when Ron Kemp put a 10mm spark plug in the center of his Flash cylinder head to "light the bonfire in the middle" I did not think anything except 14 and 18 mm plugs existed (apart from model airplanes)
I believe other motorcycles from "over the water are available with smaller plugs...(even I have one now)
Its a bit like chains and tyres once upon a time it was easy with a limited choice now its just another maze to traverse!