I used the same 320 mm rotor but used the Galfer pads same problem, Try this loosen the caliper bolts apply the the brake and tighten the caliper to make sure it is aligned to the rotor that fixed mine.
just seems like every over performance bike has one. And the engines do run hot in the summer does any one know what the oil temps are on the track ? and a lot of bikes use the oil to cool the heads and pistons
the 390 original master cylinder I heard is a 12 mm and the R6 is a 16 mm the through is short but at the lever the feel is great . Before I upgraded to the 320mm Galfer rotor and pads.
I Raced a RZ to a championship in the 80s along with a FZ600 super bike i would have killed for a brake...
Slight clearance problem hits windshield, could trim about 1/8 inch form windshield or install steering stops also wires are about one inch to short I'm using the ABS and had a custom line made and am using some 20.00 Chinese CNC levers that are nice quality. Brake feel and firmness at the lever...