I was out on the weekend and did some paying around with delfection. Running the belt deflectin tight enough to have the track creep ended up causing a bog much like you describe. One I started loosening the defelction the bog went away. This sort of flies in the face of conventional theory, but this whole Diamond Drive has forced me to change the way I think about clutching.
Yes, adjust your oil pump as well. They are super rich from factory and that too will help with the bog.[/b]