Pengaruh Pemanfaatan Gasoline 80% dengan Variasi Konsentrasi Bioethanol dan Methanol terhadap Emisi dan Coefficient of Variation pada Spark Ignition Engine Test Bed 125 CC dan Road Test Engine 1800 CC = Effect of 80% Gasoline Utilization with Variations in Bioethanol and Methanol Concentrations on Emissions and Coefficient of Variation on Spark Ignition Engine Test Bed 125 CC and Road Test Engine 1800 CC