When overhauling the engine, replacing as many of the wear prone components as possible will simplify the building process and subsequent adjustments required to set up the engine correctly.
The most vital items that require close examination for wear and damage (after the cylinder-head has been sorted) are the components that make up the crankshaft/balance-shaft/piston/cylinder assembly.
This component, and perhaps some of those below maybe required:
130311380
130321207
130351052
130371441
130375086
140201094
920261204
921221163
130411105
131011205
920151890
922001157
132BA0825
132Y0614
130011438
130081156
920434009
92055055
Pro-workshop gasket sealant 08C70K0234M to complete the job like a professional! Add as many new parts as you wish, a new piston pin 130021101 and piston pin circlips 920331226 for example, and still only pay the same single fixed price shipping cost. This component may have other applications within the Kawasaki model range - so please ensure the part-number ordered is correct for your application.