Roo

What is the black coating that is on the stock carb slides? I have never seen it before! I got my first banshee recently. I have ridden and built quads, motorcycles, and snowmachines. (lol, we dont call them "snowmobiles" here) What is the purpose of the black coating? Mine shows signs if wear and I dont want it to bind at WOT since I already ditched the TORS boxes in favor of regular caps and a twist throttle. Like I said before, this is my first Banshee- although I have worked on plenty of stuff with Mikuni carburetors before. Any help appreciated! Roo.