Parts such as the Optional Parts Gauges & Component Parts 1: Digital Meter Assy(tacho), Screw, Tapping (26h), Bracket, Meter 1, Screw, Tapping (26h) are included in the 225etd 1990 Optional Parts Gauges & Component Parts 1 parts fiche.
The Yamaha OPTIONAL PARTS GAUGES & COMPONENT PARTS 1 has twenty-four products enlisted in the schematic.
The Nut is the cheapest item from this partsfiche.