the factory oil cooler works just fine. an r1 motor was design to run at 12,000+ rpm during a superbike race. sportbike engineers taylor the motors to the extreme coditions of racing not the street. the motors are detuned via the ecu and other emission systems for street use. placing an oil cooler in the system would lead to a cooler oil temp but would put to much strain on the oil pump to push oil to a cooler.