Parts such as the Steering Stem (model K2): Bearing(30x52x16), Damper,upr, Holder,handle Lwr, Bearing(30x52x16) are included in the Rm250z 2006 (k6) Usa (e03) Steering Stem (model K2) parts fiche.
In this schematic the "Bolt" is used most often.
The most reasonably priced component used on the Rm250z 2006 (k6) Usa (e03) Steering Stem (model K2) is the Bolt.