Top end performance was the Yamaha R6’s strong point and still is. But with updated ECU and fuel injection, the highest ever compression seen on a Yamaha and variable height inlet trumpets (as used on this year’s R1), the R6’s midrange drive has been propped up. Not that there was a reliability issue with the R6, but Yamaha has revised various internals (camchain tensioner, oil-ways on the rods etc) to deal with the high rpm live it leads.