parts compatability?

i've got an 82 kz750 ltd (inline 4) and it came without wiring/lights/ pretty much anything electrical....theres a 77 kz650 posted on craigslist near me for cheap, i was wondering if any parts off the 650 would be compatable with mine...any help would be appreciated!

Pretty much nothing significant will be compatible.

Not the alternator.
Not the regulator.
Not the rectifier.
Not the ignition coils.
Not the points/igniter.
Not the harness.
Probably not the ignition switch.
Maybe a fuse or two might be able to swap over.

The best matches for your bike are the 81-83 KZ750-Ltd-4. The 80 model should be good too. Depending upon what's needed the 81-82 KZ750-E-Standard & 81-83 KZ650-CSR would be next in line. The electrics on the E are probably nearly identical. The CSR shares some ignition parts etc & has the same exhaust system & body parts.