Well, it does have to fuel a larger combustion chamber, but at lower rpm than the 6R and not much greater power (about 20% if that.) Also lower rpm than the 9R.
Fuel flow is as a rough rule of thumb pretty much proportional to hp developed (if comparing engines of similar efficiency, though often not if comparing for example an engine with radical cams vs one with mild cams where the milder-tuned engine would usually flow lower lb fuel per hp hour) and so with only around 120 rear wheel hp and mild cams, the Z1000 while being probably some increase in maximum fuel flow over the ZX-6R I'd think, is still probably not a great increase.
Which probably explains why Kawasaki was able to just swap the injectors and throttle bodies over even though the displacement is 50% greater.
(EDIT: I had read in a magazine that the fuel injection was the same between these models, but I have now found the part number of the injectors is not identical, so perhaps that is not so, though sometimes the same part gets different numbers on different bikes. Even if not, whatever injectors the Z1000 has are intended for around the 120 hp level, and furthermore, it doesn't seem like anyone has been able to really get it past 130 hp -- at least during the first more-than-a-year after it came out that I was trying to follow it, the Z1000 seemed to allow very little extra hp from pipe, air filter, and airbox mods, whereas of course the 9 readily allows tuning well past that despite lower displacement. It seems possible that the throttle bodies / injectors are the reason though I don't know.)
Just seems probably a small kind of place to start from for a turbo 9R project, but perhaps not.
