Spongy pedal after big bolt pattern conversion

Thanks for the ideas, guys. M/C should be fine, I would think. Was installed new a few years ago, but it's a good idea to isolate it and check it. I was thinking that the rear brakes needed adjustment, so I tightened them up last week. Made things a little better, but didn't totally fix it.

The calipers are kinda similar to a KH caliper in the sense that they are fixed and have four pistons. There are two bleeders, one for each side. Calipers are mounted so the bleeders are on top.

72BBSwinger - thanks for the idea on the crossover tube. Didn't even consider that. My bleeding procedure was to start with the right rear, then do the left rear, then the right front (outer bleeder first, then the inner) and then the left front (outer bleeder first).

I'll probably have to wait until the weekend to look at it.