Parts such as the Taillight: Lens,tail Light, Sub Cord,tailligh, Stay,number Brack, Collar,ajc Mount are included in the Xr600r 1991 (m) Belgium Taillight parts fiche.
The most reasonably priced component used on the Xr600r 1991 (m) Belgium Taillight is the Bolt,hex.,5x20.
With three applications this Spg-washer 5mm is the most specified part.