Answer:
in farsi goodbye is kodafez. the 'k' is really like a scratchy throat sound.
Transliterations tend to vary from eastern scripts to western European ones, but I find "kodafez" to be rather contracted, much like the English "g'bye"; and often Iranian (Farsi/ Persian) speakers do pronounce it that way. However "khoda hafez" is a closer pronunciation of the more formal expression, drawing from the Persian words for "God" (khoda) and the the name of the Persian poet Hafez.