Which port goes to which on 4-disc M/C?

The front brake line should be the rear most port of the MC.

Although it is not readily apparent from the outside, there is normally a spring located between the piston in the front bore of the MC and the piston in the rear bore. This allows the rear piston to move forward slightly sooner than the front, thus activating the front brakes first. If the rear brakes locked up first, then the car is more susceptible to having the rear spin out.

Or at least that is what my week long, in house, ASE training taught me back in the 70's (which also included 4 wheel Vette disc brakes.)