Hi Mutaito,
the official documentation for KH Spirit cranks refers to 160 or 180mm rotor. I know that NurseBen was running 200mm rotor on some of his unis.
You can try and check the disc brakes thread. However, 140mm doesn’t ring a bell.
You will also need to have the proper IS adapter to be sure your caliper seats close enough to grab the braking area properly 