Rebuilding kz650... where to buy rings?

So I'm finally going to rebuild my 1978 kz650c engine. I'm going to buy new top end gasket set, coil wires, carb rebuild kits, and tach cable. The only thing I think I'm missing is new piston rings. The number 2 cylinder has exactly 0 compression which could be from a missing stud beside it but I put oil in there and it shot up to about 125psi so I'm not sure. My question is if you guys think it's the rings where can I buy new ones?

If the compression goes up with added oil then yes, it's your rings. The oil "seals" the bad rings it so you get a reading. Bad news, no "std" (standard) rings are made for the 650 anymore. You will have to go 1st or 2nd overbore depending on what measurments you get from the cylinders. You may get lucky with some NOS rings but have only seen one set on ebay in last couple years and they went for $220! A 700cc kit (pistons, pins, rings, gasket) is available from many sources.

Example... Wiesco has one..

KZ650 1976-83
Kit includes: (4) Pistons, Ring Sets, Piston Pins, Retainer Clips, and (1) CFM20 Head Gasket
700cc
Sugg Retail $580
Dynoman $429.95
2.520" or 64.00mm
2mm oversize
Stroke - 54.38 K700 10.25:1 Cylinder boring only
Piston: 4037M06400 Rings: 2520XC Piston Pins: S522
Retainer Clips: CW15 CFM20 Head Gasket: W2486

According to Kawasaki.com the standard size is still available (part #13008-059). Ron Ayers lists them for $46.50 per set. I bought 4 sets on Bay about 9 months ago for $9 per set in case I ever need them, so they do show up on eBay sometimes. Ed

Cool, 650ed! I thought we had discussed that here and they were no longer available? Everyone gets all excited when some show up on ebay. I'll have to check out Ron...

Bluemeanie wrote:

Cool, 650ed! I thought we had discussed that here and they were no longer available? Everyone gets all excited when some show up on ebay. I'll have to check out Ron...

If you have cylinder wear (and you are not boring the engine) you might want to get the +0.25mm over ring set and shave the ends of the rings until you get the correct end gap in your cylinder. It will compensate to some degree for the cylinder wear. Not as good as boring one over and replacing the pistons and rings, but a lot cheaper.

650ed wrote:

According to Kawasaki.com the standard size is still available (part #13008-059). Ron Ayers lists them for $46.50 per set. I bought 4 sets on Bay about 9 months ago for $9 per set in case I ever need them, so they do show up on eBay sometimes. Ed

babbittsonline.com used to have the best prices on OEM kawi parts, you might want to price stock rings there.