That's only a breather, so normally a rubber pipe with a 90 degree bend in it so it runs between and under the carbs to the back of the engine, downwards and then exits at the right just aft the fairing, close to the rear belly mounting point.

Normally there's a wire bracket there which holds a few pipes together. If that's not there anymore you may simply have it exit at the bottom somewhere where it does not touch the exhausts, or like on some race bikes have a short one which stops at the back of the carbs.

Cheers
Mario