Originally Posted by coffeysm
That's not your PCV hose it's part of the braking system it's a check valve that makes it easier for you to brake. It even states on the Z1 site to put the check valve into the new hose prior to installation.
Yeah op you will need that to keep air from leaving the booster. It makes your braking way easier, and could risk a crash if it doesn't operate as intended. Careful.