Thanks for the report, Mark. I agree, the jet drills make it practical to do that job fairly easily. I haven't found any other way that will work as well.
The slight unevenness when cold sounds like lean mixture - mine doesn't do anything like that, but it did before I fixed two problems. One was cleaning the main jet thoroughly so it was 0.55 mm diameter. The other was fitting new genuine Honda intake pipe gaskets on both sides of the insulator. True, they are about $2.50 each, which I resent, but if you put them on dry, onto clean flat surfaces, they seem to last indefinitely - I've had them on and off several times without damage. It sounds to me as if you have one or other of those two faults.
