This was a project for a friend who needed a custom set of expansion chambers for his Yamaha RZ350. This special RZ350 had been modified with an Aprilia RS250 swingarm. He liked the way Spec II RZ pipes performed  so we used them as a model, but also made some innovations. I call this design “RZ350 Spec III.”

Also included in this post are some pipes for a RZ350 motor in an RS250 chassis…