This discussion reminds me of HRC titanium exhaust I got for my VF500 way back in '80s. It came in big box with 37 individual parts. No manual, no instructions on how it goes together. Only thing in box was 3.5x5" index card that said, "
cut and weld as necessary"! AHHAHAhahhahahah!!!!
You can make brake-caliper adapter to fit any caliper to any disc-rotor size using rotary table. Here's some threads of interest:
https://www.ninjette.org/forums/showthread.php?t=177974 <-- Arashi 320mm rotor
https://www.ninjette.org/forums/showthread.php?t=281767
https://www.ninjette.org/forums/showthread.php?t=182732
https://www.ninjette.org/forums/showthread.php?t=305237
Rotary-table will allow you to mill around tube-section of homemade adapter shown with beveled base (or stick bolt through and use CNC lathe). Connection at base of plate should NOT be sharp right-angle like sticking separate tube onto plate. It should be beveled/angled gently at connection. You can easily chop off 150-200gm from those adapters with more optimised design, such as threading adapter itself so you don't need to use nuts on backside. And use hollow CBR chromoly bolts. Here's some pre-made off-the-shelf caliper adapters:
https://www.svracingparts.com/store/...kets-p40099954
https://www.rsvracing.com/en/product...250-300-m4-100
Http://amazon.com/dp/B00B10DH7Q
Although for racing, I think stock caliper and rotor size works just fine with some grippy pads like Galfer. The steel Galfer floating rotor lasts forever. I'm on my 3rd season with it and there's absolutely zero wear!