Yamaha YZF 125 R, MT 125, WR 125, YBR 250. YAMAHA MT-09 13-18 FZ-09 14-18 XSR 900 2016- AS3 TOP YOKE STEERING STEM NUT RED. AS3 Performance Top Yoke Steering Stem Nut for. AS3 Performance stem nuts are manufactured from 6061 billet aluminium and are a great upgrade from the OEM stem nuts, they weigh only 21 grams and have a smooth anodized finish to match the rest of our range of CNC machined hard parts.