TOPIC:

Ok Guys, Feel free to post what you've used and experiences.  There are a few different manufacturers out there still making pistons Like IMD, Cruzin Image and Forseti. I wanted to explore the option of using KZ650 pistons because the "rumor mill" has indicated that they might be an option so I bought a "second over" version of the KZ650 piston, Kawasaki part# 13027-069 which is 63mm diameter, so......

KZ650 piston- Bottom line exactly the same as the KZ1300 piston. Read on if you wish.
To compare I took a wrist pin and inserted it halfway in a stock KZ1300 piston and Halfway in the KZ650 piston then compared 
Skirt height to wrist pin - identical
Piston ring glands- All 3 where the same height from the wrist pin. All 3 were the same thickness i.e. will take the same piston rings.
Piston crown- although it would appear that the KZ1300 crown is slightly more prominent than the KZ650 piston, as measured by a vernier they are identical. I swear that what I see and what I measured tell me that what I see is an optical illusion and maybe because the KZ1300 piston is used and has a dark color to it. I did not make a pattern to place it on each crown to compare and the only other thing that could be done would be to place a KZ1300 piston on a connecting rod and a KZ650 piston on another twined connecting rod and then do a cc check.
Piston weight- The KZ1300 piston weighed 158.1 grams and the second over KZ650 piston weighed 165.2 grams so considering that it's .040" larger in diameter, 7.1 grams difference, I wouldn't worry about it.
Valve relief pockets- Identical

 

KZ1300 piston on the left

 

KZ1300 piston on the left

 
KZ1300 piston on the left Skirt cutout identical.

 
KZ1300 piston on the left. It would appear that the crown is slightly more prominent on the KZ1300 piston but no matter how I tried to measure it, the crown height was within .002"

Being in the UK i used the IMD pistons although i am still getting on with putting it all back together i have to say that the service was brilliant , obviously cant comment on them in use yet but i have every confidence that they will be fine

In 2014 I bought the Cruizin Image first overbore kit, consisting of pistons, rings, clips, pins, gasket.
Clicky

The head gasket leaked at static pressure, cold engine. Junk. 

Pistons, pins, etc? Not sure what to say. Motor still uses oil, and I'm mentally processing steps and parts needed to refresh the top end. 

Then Cruzin kit was $250 back in 2014, same price in 2023.  

I doubt I'll use them again... 

Kawboy, I searched 13027-069 and they don't appear readily available? Found some a couple on eBay, but not a set of 6.. 
and I wonder if manufacturing has improved since 1979, thinking that perhaps aftermarket, specifically IMD, might be a better choice?

Also, looking back on my rebuild, I see entries from me (gasp) that said 'Tom from Wiseco' indicates Wiseco has made forged pistons for Z1 enterprises ... back in 2014 or, Z1 had KZ pistons..
 

Bottom line from my point of view, If you're looking for pistons, also look at the options available for the KZ650. Wiseco still has pistons available for the KZ650 and they are forged which is considered to be a better option than cast pistons.
I really wanted to measure the KZ650 pistons up and see how close they were to the KZ1300 pistons and they are so close, I can't measure any difference.

Tyler also had a set of pistons custom made from Ross Racing Pistons and they were forged as well. cost wise, I think they came in at $200 a piston. he also had Cometic manufacture a custom head gasket with fire rings to match the new bore. Cometic is renowned in the car racing scene for their head gaskets. As I remember it   Tyler's top end rebuild went really well.

Tyler's topic- New pistons finally in   

Tyler's topic on KZ rider- Oh No What have I done

From Partzilla website:

This Kawasaki 13027-069 PISTON,0.040in.,O.S. fits the following models and components:

Kawasaki Motorcycle 1980 LTD - KZ650-E1 Cylinder/Pistons
Kawasaki Motorcycle 1980 KZ650-F1 Cylinder/Pistons
Kawasaki Motorcycle 1983 CSR - KZ650-H3 CYLINDER/PISTONS ('81-'82 H1/H2)
Kawasaki Motorcycle 1982 CSR - KZ650-H2 CYLINDER/PISTONS ('81-'82 H1/H2)
Kawasaki Motorcycle 1981 CSR - KZ650-H1 CYLINDER/PISTONS ('81-'82 H1/H2)
Kawasaki Motorcycle 1979 SR - KZ650-D2 CYLINDER/PISTONS/CRANKSHAFT
Kawasaki Motorcycle 1978 SR - KZ650-D1 CYLINDER/PISTONS/CRANKSHAFT
Kawasaki Motorcycle 1977 KZ650-B1 CYLINDER/PISTONS/CRANKSHAFT
Kawasaki Motorcycle 1979 KZ650-B3 CYLINDER/PISTONS/CRANKSHAFT
Kawasaki Motorcycle 1978 SR - KZ650-D1A CYLINDER/PISTONS/CRANKSHAFT
Kawasaki Motorcycle 1978 KZ650-B2 CYLINDER/PISTONS/CRANKSHAFT

Looking at Wiseco site, they only offer this which doesn't look at all like Kawboy's pic..

powersports.wiseco.com/catalog/product/v...12216/category/4461/