On this parts fiche the Nut,flange,7mm is the most specified component.
Parts such as the Cylinder/cylinder Head: Cylinder Comp.a, Nut,flange,7mm, Bolt C,cylinder S, Bolt,stud 2,8x25 are included in the Nsr125r 1999 (x) Italy Cylinder/cylinder Head parts fiche.
The most reasonably priced component used on the Nsr125r 1999 (x) Italy Cylinder/cylinder Head is the Nut,flange,8mm.