If the banshee runs better with Riva pipes, then why didn't yamaha make it that way? If the banshee runs better with port work, why didn't yamaha make it that way? If the banshee has more power with the original rz350 powervalve setup it was originally derived from, then why didn't yamaha make it that way. Some of the answers lie in money, liability, consumer msrp, ease of manufacturing, and assembly. If you want to run twin carbs go ahead, but here is my feedback above from the single carb setup compared to stock twin carbs.