Hello Wrgoo:
I am not an expert either, but for years, I have wanted to attempt this modification. In short, I have done a fair amount of research and reading on what this would take.
I have performed troubleshooting on non working FI systems on GPZ's and in the past, narrowed the failures down to weak fuel pressure regulators and fuses. So overall, fairly basic failures.
Here is my understanding.
1: Kawasaki originally partnered with Nissan on the fist EFI system in the late 70's to be introduced in the 1980 and 81 model years, on the KZ1000 Classic (USA) and in the KZ1000 H in (Europe) With the H model mainly offered in Germany if my research is correct. The First systems were a direct copy of the 280 and 300 ZX "Z car" hardware.
The early KZ EFI was fairly dependable, offered 2 to 4 more HP and was generally a successful roll-out. Problems arose when dealerships didn't understand it, or when the bikes were out of warranty, people usually scrapped the FI and installed a set of smoothbores or VM carbs.
In 1982, Kawasaki introduced DFI, a revamped version and much improved. Most FI systems for the rest of the 80's retained this DFI configuration until FI was phased out by 1989.
Regarding the failure of processors, most were due to people starting their bikes with weak batteries. 30 years ago, battery tenders were not used as much as today, and the weak electrical state would damage components inside the processor. Not to mention some of the weak electrical generation, or lack thereof on the KZ's charging system.
About 15 years ago I believe David E. did a mock up system on a mule engine he had and written an extensive article on. Some of my knowledge comes from his article and it seemed to work ok. One of the main modifications was altering the fuel rail to fit from the ZN to the KZ's frame. (Remember the frame on the ZN is completely different than the KZ.
I always felt it a shame of all of the ZG13's that have been scrapped over the years in the EU. I bet there are a few of those FI systems either in the junkyard or trashcan, long gone.
Ok, so flash forward to today and what is available:
1: The ZN and ZG OEM FI system is a batch system. I.E. working in unison with Kawasaki's wasted spark ignition system, the injectors fire in unison on common circuits.
2: What can be done to update or modernize this system? By adding sequential injection it would add a lot of efficiency. This means adding the following
Crank angle sensor
Cam sensor
Scrap the OEM processor and use the Mega Squirt controller. The Mega Squirt is supposed to work under Batch fuel injection as well, without the CAM reference. Per Matt Cramer at DIYAutoTune.com
It seems the easiest way to add FI to the Z or KZ is using a combination of Factory parts, with a modified fuel rail. You are then faced with the decision of using the OEM processor or using the Mega Squirt controller.
I think recycling the ZG or ZN throttle bodies and most of the OEM components is the best way to add FI to this bike.
Go back and review David Ewing's three part article on FI and it will provide a good background on how to tackle this modification.
If I ever tackle this project, my path would be to use all of the existing parts and refurbish or replace the fuel injectors, being a higher wear item. Also the fuel pressure regulator on this system is one of the highest wear items and they do wear out from time to time. (Needs to keep the fuel rail pressurized to around 36psi)
If I felt I was not gaining the efficiencies I was looking for, then I would start by adding the Mega Squirt controller with the thought of adding the crank and cam sensors to go from Batch to sequential fuel injection.
The Mega Squirt (Not the Micro Squirt) provides the most bang for the buck as you may want to grow into the Sequential elements down the road.
I hope this rambling of mine adds some positive light on the subject. Or confusion.. lol.
Todd.