Here's the pedal assembly, tucked in front of the exhaust and magneto:
When you depress the brake lever it will pull a rod attached to a lever, connected to a cross shaft. I haven't build the lever or rod so I can't sow it at this point, but it's pretty easy to grasp. The crossover shaft rides in a shouldered cup (one on each side of the frame) with a bronze bushing. The cups look like this:
The crossover rod is 1/2" and the lever is 1/4". I put 4 flats on the end of the rod and put a square hole in the lever to keep anything from slipping. To hold the lever on the end of the rod I drilled and tapped for 5/16" coarse. One end of the assembly needs to come off for maintenance...the side not shown will be welded on. Here's what the M/C lever side of the shaft looks like:
Here's a side view of the rod and lever in the bike (no brake plunger):
Here's the lever from above:
Originally I was using a flat 1/4" lever spaced away from the frame, instead of the zig zag you see above. I was worried the bottom of the lever would drag on hard left turns and bend the crossover shaft. I ended up with the zig zag to span the gap and maintain ground clearance.
Anyway - that's about as far as I've gotten. I need to make a smaller plunger, build the rod and lever for the pedal side and figure out how the thing will be adjusted.