I my Sabre leaks fuel when I start the engine. I did not ride motorcycle for few months. After I started engine for the first time after this brake, I had large puddle of gasoline under the bike after minute or so. I removed crankshaft cover on the side of kickstand and found pipe which fuel is coming from. Not just dipping, but nice steady stream. This happens only when the engine is running.

Please see the picture with blue circled pipe. Does anyone know what this pipe is? How do I fix it? Is this carb vent pipe? I suspect overflow needle valve. If so, do I need to remove and clean carbs? I watched some YouTube videos, and carbs cleaning seems a little bit above my current skill level. Sure, want to make sure I do not start learning it, till I know, that this is the issue and only way to fix it. Any suggestions are more than welcome.