I've done a ground-up CB350 restoration. Found that the advance unit -behind the points- was stuck. Fortunately, I found it at rebuilding stage, because I didn't install anything that I haven't checked before. Check that yours works fine. Unfortunately you will have to remove the points plate again, but if you use a marker to signal the retaining screw position, you will be well off just by reinstalling it at the same position without having to adjust everything again.
Problem with points timing on the CB350 is that is a trial-and-error method, a sucessive approximation method. You adjust left point gap, left point firing, and when you move the plate to adjust the right point the left one has changed. The firing point hasn't changed, but the amount of time the point remains closed has changed. So you have to redoit again in order to make both points remain closed more or less for the same time, with the certainty that in a few miles, the points wear will ruin all the adjustment.
