You won't find the mix screw or it's associated parts (spring, washer, o-ring) on the 650 carb diagrams because they never sold any of those parts. The screw was capped over at the factory and you weren't supposed to mess with it. Yamaha uses similar CV carbs on lots of their other bikes and many of them do list mix screws. So, through careful research and measuring on eBay and from those other model's parts diagrams, I was able to determine this 12R-14105 screw was the same one used in the 650s. Took a chance and bought some, and they are indeed an exact match.