As a result of extremely competitive market environment and severe emission legislation, motorcycle manufacturers are giving increased focus to the lubricant as a potential tool to improve engine performance reducing at same time tailpipe emissions and fuel consumption. However, due to very specific hardware constraints, application of highly efficient low viscosity oils to modern motorcycle requires careful formulation approach and thorough testing procedure. Previous work carried out by Castrol and described in SAE paper # 2011-32-0513 indicated that optimized, low viscosity motorcycle engine oils, formulated with dedicated technology to combine optimum clutch compatibility with engine and gearbox protection, can bring significant increase in engine power and acceleration in comparison with commercially available lubricants. This paper describes the progress of the development work, aiming at further understanding potential benefits and constraints arising from the application of low viscosity, highly efficient engine oils to current motorcycle engine technology. The work included the evaluation of the fuel economy potential for experimental low viscosity formulations using a sport tourer motorcycle fitted on chassis dynamometer, followed by extended high speed engine durability evaluation of one of the formulations on two different super sport motorcycle engines, representative of latest generation hardware technology. Results of Fuel Economy tests showed that carefully formulated low viscosity lubricants can provide reduction in fuel consumption when compared with conventional, commercially available products. Both the durability test programs were successfully completed with key engine and driveline components in good conditions at end of test, confirming potential applicability of low viscosity engine oils to modern high performance sport bikes.