Selecting the right engine oil determines the performance and service life of a motorcycle engine. However, empirical evidence on the performance differences between full-synthetic and semi-synthetic oils under real-world operating conditions is still limited. This study comprehensively analyzes the performance differences between the two oil types in a 250cc 4-stroke motorcycle engine using an experimental approach with rigorous statistical methods. The experiment was conducted on a Kawasaki Ninja 250 RR Mono by measuring four critical parameters: engine vibration, oil temperature, torque, and power at various engine speeds. The results showed highly statistically significant differences in all tested parameters (p < 0.05). Full-synthetic oil demonstrated superior performance with a vibration reduction of up to 30%, a reduction in operating temperature of almost 2°C, and an increase in torque and power of approximately 2-3% compared to semi-synthetic oil. Further analysis revealed that oil type had the greatest influence on engine mechanical stability, followed by thermal management and power efficiency. These findings provide empirical justification for oil selection based on usage profile and performance priorities. This research contributes to the development of evidence-based engine maintenance strategies and provides practical guidance for users in optimizing motor vehicle performance.
Wagino et al. (Tue,) studied this question.