On this parts fiche the O-ring (50w) is the most specified component.
Parts such as the Starting Motor: Brush Set, Washer(3sx), O-ring(1rl), Bolt, Small Flange are included in the Wr450fs 2004 5tj7 New Zealand 1c5tj-100e1 Starting Motor parts fiche.
The Wr450fs 2004 5tj7 New Zealand 1c5tj-100e1 Starting Motor consists of nine pieces with the Motor Assy being the most expensive.
