YOYO!
I think people underestimate the importance of correct timing.
I had mine set at 1.2mm btdc--shitty performance/acted like a rich running condition.
I advanced it to a little less than 2mm btdc, which yielded MUCH better performance throughout the entire rpm range:)
I would try advancing it, at least a little, and see what it does.
Hope that helps!!
Willie.