Difference piston rings part numbers KZ 1000

My head gasket is leaking a little oil and i want to change the gasket this winter. Also a good opportunity to do the head, valves and hone the cylinders and renew the pistonrings. Compression is OK. But i discovered that there are two models. Does somebody know the difference between the Kawasaki Z1000 piston rings part nr13008-5012 year1977/1981 and part nr 13008-5035 year1981/1986. I changed my pistons of my Z1B in 1985 to Z1000 pistons so i think it must be the part nr 13008-5035 but i dont remember the partnumber anymore.And the guy who did the job RIP.
Willem
 

The J and R models (1981 onward) have 998cc (69.4mm bore) engines, the 77-80 models have 1015cc (70mm bore). To figure out what you have in there you'll need either the bore or the piston size (~69.35mm vs ~69.95mm).

Not very helpful because I can’t tell you 100%. As far as I know the 81 and up pistons will be 18mm wrist pins. 77-80 will be 17mm which is the same as the Z1 and Kz 900’s. So unless you highly modified your engine to run the 81-up j crank you should need the 13008-5012.

According to the manual, the 81-onward pistons use 17mm wrist-pins. I wasn't sure about compatability either so I checked Still not sure if the j pistons would be a straight swap, though. Anyone?

I did not change the Cranckshaft, only new pistons  with rings and new wristpins. 

Your 900 with 1000 pistons will be using the earlier 1977/80 - 13008-5012 rings so use those.
The later rings won't fit as they are for the J 's smaller bore.
You won't have J pistons fitted as suggested because although they have the same 17mm piston pin the pin height is lower on the J piston by 1mm so won't run in a kz block without a 1mm spacer at the base.
Only the Bathtub head GPZ1100/1100R used the 18mm pins.

Another source to back up the previous statements.

www.aperaceparts.com/tech/techkz1000.html

APE says the J and later motors have shorter connecting rods along with a lowered pin hole in the piston.

The page also talks about which parts mix and match.

Hi new to the scene . I have some kz900 cases will kz1000 internals fit ? 
grateful for any help

wrote:

Hi new to the scene . I have some kz900 cases will kz1000 internals fit ? 
grateful for any help

As long as it's the same type with kickstart provision and not the later J type then everything will fit as the 1000 is just an overbored 900.
Gears clutch etc are the same parts.
The only issue you may have is fitting the 1000 barrels on the 900 cases as some crankcase mouths will need opening up very slightly to take the 1000 liner spigots.
Also watch out for later Mk2 1000 engines which have extra teeth on the crank and cam sprockets which should be paired and not mixed with the earlier stuff or you will throw out the cam timing and risk bending valves etc.
There are a few other differences with the MK2 such as generator type etc which are best answered individually if that is the donor engine type you have.
 

Thanks fo or your help 
fantastic