Here we have a CTC Yamaha TY250/350 Mono 7075 T6 aerospace grade lightweight aluminium steering stem kit.
This is a direct replacement for the original steel steering stem. This is available as a bare stem or with an aluminium castleated nut, top bolt and tapered headstock bearings.
This weighs in at 1/3rd of the original steel parts saving a massive amount of weight straight of the front end of your bike.