Parts needed to add a second brake rotor to a Honda CB K series motorcycle for improved braking:

Right hand CB750K fork leg with lugs to mount swinging caliper

New brake caliper mounting swing arm

New Honda fork seal

New Brake Caliper

New brake pads

Brake rotor

Goodridge braided brake lines with additional line for second caliper

New honda rigid brake pipe

Longer brake rotor bolts will be needed. The kit will work with the original master cylinder. The hydraulic leverage ratio will actually improve.

The fork leg has some scratches in it which could be polished out. The caliper is unused but showing some surface corrosion from sitting on the shelf. The rotor is lightly used. All the brake pipes are new.