I had the cam & big bore upgrade done at the 12,000 mile service. While it was not a big difference (like a different motorcycle) it was a noticeably improved, smooth, responsive and fun motorcycle. Approx gains were HP=10, TQ=6
Do the cams (813 grind for example) when/if you do the 904 big bore. Little benefit from the increased cc's if you can't flow enough fuel into them. Air box mods and free flowing exhaust of course. And speaking of fueling, a custom dyno-tune would then be needed.
I'm glad it's done, and I did it when I could afford it.
