most road racing bikes here in the uk are only allowed to use distilled water , with no problems , once new a guy who spent weeks trying to fix a overheating problem after fitting a rg500 engine to rgv250 [trying bigger rads etc,] turned out he had not mixed his coolant with water, some coolant is thicker than water slower circulating, dont know much about evan coolant but if it does not boil until 365f is going to be hard to know when your bike is over heating? i would not use a lower psi cap , the more your pressurise water the higher the boiling point,