In this schematic the "Screw-washer,4x16" is used most often.
The most reasonably priced component used on the Cr250r Elsinore 1990 (l) European Direct Sales Carburetor Optional Parts Kit is the Screw-washer,4x16.
A sample from the products for the Carburetor Optional Parts Kit include: Needle.set.jet, Jet,slow,#50, Jet,slow,#52, Needle Set,jet.