The most reasonably priced component used on the Ksf250-a1 Mojave250 1987 Usa Canada Cylinder/piston(s) is the O Ring,18mm.
Some items from this specific schematic: Clamp,cooling Hose, Ring-set-piston Ll,o/, Bolt-flanged-small, Cylinder-engine.
With a quantity of two pieces, the Bolt-flanged-small is the most used part in the CYLINDER/PISTON(S) diagram.