Parts such as the Repair Kit 3: Oil Seal (6e5), Key, Woodruff (6e5), Insert, Cartridge, Oil Seal (6e5) are included in the L250etd 1990 Repair Kit 3 parts fiche.
On this parts fiche the Bolt (697) is the most specified component.
The Yamaha REPAIR KIT 3 has twenty-seven products enlisted in the schematic.