On this parts fiche the Bolt,brake Disc is the most specified component.
This Rear Wheel (model K) diagram displays the required parts for the Dr600r 1988 (j) (e02 E04 E06 E15 E16 E17 E18 E22 E24 E25 E34 E53 Rear Wheel (model K).
The most reasonably priced component used on the Dr600r 1988 (j) (e02 E04 E06 E15 E16 E17 E18 E22 E24 E25 E34 E53 Rear Wheel (model K) is the Washer (17x30x3.2).