Rebuilding a well worn or damaged engine inevitably includes new pistons, crank-shaft/con-rod (little and big-end) bearings and a host of other small parts that are better replaced than reused; piston-pin, circlips, con-rod bolts (which should always be replaced to allow the correct torque to be applied when tightening).
In short, this is a task for skilled mechanics; but one thing for sure, the more components you can afford to replace the better the results.
Of course, you may be lucky, and only need, perhaps, new piston rings 130081133
, either way you may wish to consider some of these related components listed below:
Don't forget to order all the new gaskets, seals and gasket sealant 08C70K0234M you will require. Add as many items as you wish to the same shopping cart, new piston circlips (snap rings) 920331151 for example and still only pay the same single fixed price shipping cost. This component may have other, sometimes unrelated applications, within the Kawasaki model range, so please always check by the part-number rather than the description prior to ordering.