I just pulled out a 1979 piston with rings till attached, and I'm kicking myself for not looking at them close up before. Their history is unknown, but my bet is they are. Some rings on those pistons were stuck, a good indicator for authenticity and a long time non running old bike.
The interesting thing is - the top ring doesn't have the bevel! I think we are onto something here, especially in regards to the infamous oil consumption and the cruzingimage ring style. I think Kawasaki paired them up with those early 5 holes only pistons. Less holes and no bevel top ring for an early model. I think cruzingimage rings are stylized after them - the 1979 rings. After feedback, they incorporated the beveled top ring and drilled extra 5 holes below the oil ring.
That's all before I forget it LOL! I think a good direction for guys with the 79 models (no idea if later year bikes had them as well, depending on where they were made), would be to source 10 hole pistons (each side!!) and replace, and get those rings with bevel to complement them. A good upgrade when tearing an engine down anyway.
Personally, I would buy a set of later pistons from eBay. Or maybe ask here ? Also, posting on facebook in the KZ1300 forums can be very fruitful.
I have 12 of these later model pistons and I will be using 6 for my engine. I haven't sorted them out yet and wanted to keep the other 6, but if you can't find any at the point of assembling the engine there is a possibility I would let you have them. That would be months from now though.
Drilling holes - 6 pistons, 60 holes... round and beveled surface, hmm... I'm not saying it can't be done in a precise way without damage, but personally I would forget about it, without a question. I'd clean them nicely and put them on a shelf for display - KZ1300 pistons! Pretty cool. And you have those cruzingimage rings to go with them as well!
I bought (with Stan's help and Facebook - Thanks!) a very good second hand set of later pistons with 10 oil holes in each. I also bought the IMD rings and put those on and clocked them as per the diagram earlier in this thread.
You can very clearly see the top ring is chrome plated and has a beveled edge and the second one is black.
I guess they are now ready to go into the block...
Paul, is it a photo angle or this piston looks different? This one looks flat with a large bevel. Did you compare them to your old pistons? They should look exactly the same except for the extra holes. The seller advertised pistons for KZ1300. I am afraid these look like ZN Voyager pistons. That would be a bad mix up. Did you confirm with the seller what he has? Although I was just a messenger, I'd feel bad if these are not the right ones.. I hope you didn't install them just yet...
No, I have not yet fitted them, they are still in a tin.
Here is a pic of what was originally in the bike...
HOWEVER, that particular block and set of pistons was beyond salvation, so I chucked those and bought a second hand block from US, and those pistons are the ones on the left here - compared with the new ones that you think are from a Voyager on the right.
Why is this not good? They seem to fit OK in the bores... (I gingerly tried without the rings)