On this parts fiche the Seal Valve,stem is the most specified component.
This schematic depicts all components used in the Cb250p 1996 (t) Poland / Plr Gasket Kit A partslist.
Parts such as the Gasket Kit A: Gasket,carb.insul, Seal Valve,stem, Gasket Kit A (nas), Gasket,cylinder (nas) are included in the Cb250p 1996 (t) Poland / Plr Gasket Kit A parts fiche.