This is the absolute first thing you MUST do.
Wash out the fuel tank!
You see, there is a lot of "stuff" in there left over from the molding process and you don't want it running into your carb and clogging it. We forgot to heed this advice and the result was junk in one of the carbs.
We had these apart a few days before putting the jets from the race kit in, and they were both clean. Added fuel to see how this one ran, and it ran poorly. After a while it was running gas out of the drain line, the float valve was stuck open and time to tear it down again. We tried to take some pictures of the metal shavings and other junk in the tank, but they didn't really show anything. But what came out when we drained the gas through a coffee filter is another thing.
So just do it, take it off before you put any fuel in the tank, remove the filler cap, remove the petcock, and wash it with soap and a lot of water to flush the junk out of your tank!