I came across something odd on Perry's carb website. I went to look up a perry carb for my ST S90K (just for the heck of it) and also my 2 K&B sportster .65's. What I found odd was the table calls for a 4500 carb for my S90K which has a .340 top and .590 bottom and the sportster calls for a 4600 which is .340 top and .625 bottom. I am guessing this is to promote fuel draw?