This study investigates the effects of swirl ratio and compression ratio on the performance, emissions, and brake-specific fuel consumption (BSFC) of a motorcycle engine using a simulation conducted in AVL CRUISE M soft-ware. The results indicate that an optimal swirl ratio of 0.5 increases engine power by 1.33% at 7500 rpm and reduces CO and NOx emissions by 24.5% and 10.29% across different speed ranges. However, a higher swirl ratio of 2.5 results in a 2.63% increase in BSFC due to aerodynamic and thermal losses. A high compression ratio in the range of 7 to 11 improves power out-put by 10.67% and reduces BSFC by 10% at high engine speeds, but leads to a 9% increase in NOx emissions and causes engine knocking at lower speeds. These findings provide a scientific basis for the design of fuel-efficient and environmentally friendly engines, while also suggesting that experimental validation is needed to ensure practical applicability.