Lucky for you, we have a float bowl drain screw. Just unscrew it some and fuel will start to drip out.
Don't rush this process or you'll make a huge flammable mess!
Once it drained, you can do whatever maintenance you want to do on the bike.
Now, that being said, unless you're going to do a total rebuild of the carb, you don't really have to drain the float bowl. The only thing that draws fuel from the bowl is engine vaccuum. So you can do quite a bit of carb play without losing any fuel.
