This study aims to determine the effect of variations in the levels of bioethanol from cassava in pertalite fuel on engine performance and exhaust emissions of injection motorcycles. The background of this study is based on the high consumption of fossil fuels and increasing air pollution so that renewable energy alternatives such as bioethanol from cassava are needed. In this study, an experimental method was used with several variations in Bioethanol levels of 10%, 20%, 30%, and 40% which included testing engine performance and exhaust emissions. The results showed that a mixture of 20% bioethanol (PBS20) produced the best performance with a maximum power of 7.2 HP and a maximum torque of 16.07 Nm higher than pure pertalite which produced 6.4 HP and a torque of 13.27 Nm. In the exhaust emission test, PBS20 also showed the best results with the lowest CO emission levels of 0.26%, HC of 46 ppm, and CO₂ of 3.9%. This shows that the use of bioethanol from cassava as a mixture of Pertalite can improve engine performance while reducing vehicle exhaust emissions.