One more major discovery.
The frame, along the bottom edge, right between the drivers, was squeezed or bent slightly together.
This has probably been a major source of the trouble all along. When I had it apart,
I notice that the gap between the split frame halves got really narrow toward the front, and comparing this
to another Mikado, I confirmed that that just isn't right. I inserted a .030" shim to keep the bottom frames
spread properly, and the improvement was tremendous. Every bit of slow-down or bind disappeared.
Surprisingly, there is no support between the frames along the bottom edge. I would have thought there
would be a built-in plastic spacer as a standard part, but I suppose Kato was relying on the fact that the frame is
pretty rigid and tough.
Just another thing to remember about split-frame engines...
