Question fo Jeff @ Z1E

Jeff you da man

Hi Otakar,
In seeing if I could help Scatdrat find rings here’s what I found. I have a couple original KZ650-B1 and KZ650-C1 parts catalogues that show the earliest 1977 KZ650 STD size piston ring set is part number 130089-5007 with instructions to use part number 13008-059 when the supply of the original number was exhausted. You are correct; the Kawasaki.com site is screwed up for the KZ650 B&C models in that it doesn’t list any part number for their STD rings even though they take the same rings as the ’78 – ’83 SR, LTD, and CSR which are listed as 13008-059. My question to Z1E was intended to determine if the OEM rings are still available as some folks appeared to be having trouble finding them. I have squirreled away 4 spare sets of NOS rings (13008-059) and pistons (13001-1002) that I bought cheap ($125 for the works) from eBay in case I ever need them for my KZ650-C1. Ed

Just a touch off topic here but what were the measurements for an 83 750?

Z650 rings are available in std size, here in the UK. Expensive at over £50 each piston. europe dealers have them too. Word of warning, Hastings rings of 62 mm will not fit the piston, they are too thick and would require the piston ring groove to be machined out. Not a good idea. hastings rings may fit otakars bigger bike, but they definately will not fit a Z650.

Jim Croft wrote:

Z650 rings are available in std size, here in the UK. Expensive at over £50 each piston. europe dealers have them too. Word of warning, Hastings rings of 62 mm will not fit the piston, they are too thick and would require the piston ring groove to be machined out. Not a good idea. hastings rings may fit otakars bigger bike, but they definately will not fit a Z650.

Are your upper two ring grooves not 1.5mm? I have never seen Kawasaki use a thinner ring. Even on their smallest piston they use which is only 37mm, they use a 1.5mm ring grove. The only thing I had to reuse was the spacer ring in the oil grove, which I mentioned earlier. Hastings makes rings in various thicknesses 1.5mm being the thinest. I doubt very much that the 650 uses 1.25mm or 2.00mm rings. I just checked a hastings ring in a Kawasaki ring grove and they fit perfectly. Believe me that the #4807 or the 2C4807 will work in a stock Kawasaki (ART) piston.
The piston in the picture is an example of a Kawasaki piston with a 1.5mm ring grove. So I doubt that your ring grove is narrower. Also the KZ1300 uses the same pistons as the 650, they only have a different dome to change the compression, due to their very long (71mm) stroke. We used to use KZ650 stock pistons in the KZ1300 stock bore to increase the compression for stock racing.