As I mentioned, there is no adjustment for anything other than idle mixture, you would have to get a larger main jet.
You could have a partially plugged main jet from "varnish" build up. How clean is your carb?
Unless someone has changed things from stock, trying to solve a problem by changing stock settings only compensates for something else which is wrong. Trust Honda, they really are better than us at figuring this stuff out.
Have you checked the timing?