I pulled the Mikuni carb on my wife's bike. It has air and fuel filters and thanks to a petcock that seeps a little, the float bowl stayed full of gas. Amazingly, it too harbored salt crystals. (See Picture) I'm thinking the only access to her bowl was through the gas line. I theorize that there was salt in the race gas we purchased from the truck. As the gas evaporated and refilled the bowl, it became concentrated and formed crystals. The same thing happening in two different bikes with one source of fuel. I'm going to post this in the BMST page to see if anyone else had this happen.