Local SoCal FJ riders can bring their wrong-size valve shims in to Pasadena Yamaha and swap them for right ones. Just ask for Kel.
To avoid "leakage," he'll only do one-for-one swaps, but if you're in the L.A. area and need a shim or three, just bring your trades on by!
Or call him at 626-577-3000 to make sure he has the one(s) you need before you make the trip.
Hope this helps,
threejagsteve