In the successive step of the study, in order to evaluate the cold extra emissions and transient durations of the sample of two high-performance motorcycles, the experimental test procedure measured exhaust emissions during ECE?UDC DC of each vehicle. The tested motorcycles are fitted with electronic fuel injection systems, allowing the control of fuel feeding and enhancing catalyst efficiency also in cold transient; the on-board central unit controls the fuel injection strategy with feedback signal from the oxygen sensor placed in the exhaust pipe. In these conditions, the cold-start emissive behavior of these vehicles was investigated under the original fuel injection strategy. Global information on the cold-start transient of the two tested motorcycles was deduced by applying the whole analytical procedure on the measured exhaust emissions of the vehicles. The data so obtained are summarized in Table4.