: Engine vacuum is required to open the petcock's auto-shutoff valve. A vacuum hose runs from a port located on the intake under the #2 cylinder (the second carburetor from the left) directly to the petcock.
: These are typically the larger hoses that vent to the atmosphere or connect to the airbox system, sometimes confused with vacuum lines. Visual Resources for Routing 2000 cbr 600 f4 vacuum hose diagram
Vacuum System Routing and Diagnostics for the 2000 Honda CBR600F4 : Engine vacuum is required to open the
Honda does not publish a standalone “vacuum diagram” in the owner’s manual. You need one of these: 2000 cbr 600 f4 vacuum hose diagram