Yamaha Float Chamber Cover 99999-04145-00. Overview. The Yamaha Float Chamber Cover 99999-04145-00 is a genuine original equipment manufacturer component designed to securely seal the float chamber within the carburetor assembly. This cover plays a vital role in maintaining proper fuel containment and pressure, ensuring consistent fuel delivery and stable engine performance.. A properly sealed float chamber is essential for efficient carburetor operation. Over time, covers can become warped, wor