If the SS motor is tuned like the B12 (mild cams, mediocre compression, runs on regular, lots of bottom end, but flattens out well before redline), and I suspect with carbs even smaller than the 2G B12's Mikuni BSR36's, it is, I think 40's would be too big. Unless you're planning on some mods to bring it up to (or beyond) GSXR1100 type cam & compression specs.