Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
I guess it's possible that one has a non std (perhaps from another Honda) fitted to make it different, either intentionally or by mistaken substitution.
That's the one thing that annoys me most. It was the same when I had my 400/4; too much rotation from closed to open. Needs a throttle tube with a higher cam.
Most peculiar! My 400/4 has about 100 degrees stop to stop and I'm sure it's getting full throttle. More investigation needed.