Anyone know where I can find a rotor spindle screw, specifically for a 356R, but they are most likely all the same. Or, which is doubtful that it would be easily found, the thread size for the screw.

Thanks

https://www.yamaha24x7.com

I have used the US Consumer portal here to order dozens of little pieces I needed for my horns. They have a great tool that lets you search for a horn and then order exactly what you need right off of the schematics. It's also eye opening as to how many of their horns share parts!