81 kz650h1 low voltage to cdi box.

so i think i have found the root of my problem. the guy at the motorcycle clinic said that the cdi box wont fire unless i have 10.5v to it. well with 12v to the coils positive wires, im only getting 9.5v to the cdi box power. (yellow/red wire) any ideas what to look at or for?

Maybe trace the circuit using a wiring diagram and clean all the connectors feeding the circuit to the ignotor?