The use of alternative fuels is one strategy to reduce reliance on fossil fuels and curb vehicle exhaust emissions. One viable alternative is ethanol derived from molasses. This study aimed to investigate the effect of adding molasses-derived ethanol on the engine performance and exhaust emissions of a Honda Vario 150 motorcycle. Four fuel variations were tested: pure Pertalite (E0), Pertalite + 5% ethanol (E5), Pertalite + 10% ethanol (E10), and Pertalite + 15% ethanol (E15). The parameters evaluated included power, torque, and exhaust emissions (CO, HC, and CO₂). The results indicated that the blend of Pertalite with 5% ethanol (E5) yielded the best performance, achieving a maximum power of 12.1 HP at 7,000 rpm. The addition of ethanol reduced CO and HC emissions due to more complete combustion, while CO₂ levels increased, signaling improved combustion efficiency. However, increasing the ethanol content to 10% and 15% resulted in a decline in power and torque, attributed to the lower calorific value of the fuel blends. In conclusion, a 5% addition of molasses-derived ethanol represents the optimal composition for enhancing engine performance while producing more environmentally friendly exhaust emissions compared to pure Pertalite.