The engine on the R15-S is the same 1-cylinder, 149 cc liquid cooled and fuel injected, 4-valve unit but as per the Yamaha India’s official website, surprisingly the R15S generates maximum power output of 16.36 BHP @ 8, 500 rpm and a peak torque of 15 NM @ 7, 500 rpm. The R15 V2.0 develops max power & torque of 16.8 BHP & 15 NM respectively. But R15S will definitely get a benefit from the reduced weight. The gearbox has also been kept the same as version 2.0, keeping the ratios of the 6-speed unit same as the on-going model. I love him R15