1. take tank off, find ECU connector, back-probe connector where pink wire goes in. Key ON, pink wire voltage = ???
2. Trace fuel-pump wire where you measured 4.83v. to other end where it connects to fuel-cut relay. Then measure voltage there. If you're measuring +12v at relay and only 4.83v at other end, where did +7.17v disappear to along way??
BTW, did you get brand new OEM harness from authorised Honda dealer? If you got used harness, we'll have to test every single wire to make sure harness is fully functional. Otherwise, you're gonna be chasing troubles previous owners created just like original harnesss.
You want to test system as wired in working configuration. Otherwise tests aren't valid. For example bypassing pump. Not sure how you did that, but you'd have to do that full-time to ride bike. Such as holding test-leads/jumper wires on pump in order to make it run.
ECU's not problem because all it says is, "turn on pump". Which relay obeys and sends +12v to its output terminal. You've already identified problem. Now you have to figure out why that power disappears along way to pump. Trace wire between fuel-pump relay's output terminal all way to pump to figure out why you're losing 7v along way.