With these differences you (Wayne) and Riccardo are talking about, i beleive it's quite safe to say there was no rhyme nor reason to why a 17 hole is on 576 and a 11 hole is on 1081. Ditto short/long nuts. KP's 248 has a pair of early radiussed exh.flanges and a pair of later un-radiussed flanges. Hard to believe these flanges were changed out after the bike left the factory. Honda used on the assembly line parts that were sent to the line. Short/long nuts, 11/17 holes was not a concern for assembling motorcycles that were hot in demand and short in supply. I've visited w/ Vic on this issue, he believes the same.