Crank Interchangeability (650/750)

I'm in the process of putting one of my 750 Turbos back together. Kawasaki website indicates that the 750 Turbo uses the same crank as the GPz. When you look a little further, some of the KZ 650s use the same crank as well. The funny thing is, not all the 650s and not all the 750s use the same crank. This is probably best shown where the 83 CSR, depending on serial number has either one crank (labeled "Cranksaft Assy"), and with subsequent serial numbers has the GPz crank (labeled "Crankshaft Comp").

I know all the cranks are the same size because the stroke is consistent throughout all the models and because all the bearings, seals etc use the same part numbers throughout.

Now to my problem, I've a couple of KZ650 cranks and I believe they are of the different part number than the Turbo/GPz. There is no outward difference between them and the 750 crank. What would the difference in these two cranks be? As well, has anyone had any experience swapping between the two? The Turbo (especially since it has 810 pistons) would be putting out a lot of HP and since it has already eaten up one crank, I would like to be sure before I invest in a rebuild.

I don't know why some 750 cranks may be different, but the difference between the Turbo and the 650 cranks may be the cam drive gear. 650's switched to a HyVo chain cam chain at different years, depending on the model.

What caused the first crank to be wiped out?

Spun a con rod bearing. Was going about 240 km/h (150MPH) at the time. Didn't know at the time that a Barnett Clutch was a bad idea.

Regarding the crank, I'm not so sure it's about the change in cam chains - in the 83 650 CSR listing on www.buykawasaki.com , there are 2 different cranks listed based on ser number, but all the other parts (including the cam chain) are the same part #.

The turbo has different rods (larger wrist pin) and primary chain (same size, but stronger)than the rest of the 650/750 lineup, but depending on the model, the crank seems to be the same.

Typing in the ZX750E2 part number in the parts search box shows the following models use the same crank.

81 KZ650 H1
82 KZ650 H2
83 KZ650 H3
84 KZ700 A1
83 KZ750 F1 Shaft
83 KZ750 L3
82 KZ750 N1
83 KZ750N2
84 ZN700 A1
85 ZN700 A2
91 ZR750 C1
92 ZR750 C2
93 ZR750 C3
83 ZX750 A1
84 ZX750 A2
85 ZX750 A3
84 ZX750 E1
85 ZX750 E2

It makes sense to me that the Turbo would use stronger rods, wrist pins, and primary chain due the the increased hp of the 750 turbo. It is interesting that the KDX200 uses the same wrist pin (at least some years).

I probably have an extra crank for a ZX750A, but I'd have to check to make sure.