2003

Allegedly all-new and undeniably all-R6, it rolls into the most serious 600 class in years some eight pounds lighter and packing three additional horsepower. A radically refined aluminum chassis aims to top any 600-class cornering comparison, while its artfully sculpted skin keeps the silhouette fresh. Starting out with a class-leading package makes radical change unnecessary. The story starts with a revamped ram-air inlet, feeding what Yamaha says is a more efficient pressurized airbox. Downstream, four YZF-R1-type 38mm throttle bodies provide the most predictable innovation: electronic fuel injection. Move deeper into the engine and changes are more subtle. Waging war against friction and pumping losses--power-sapping crankcase pressure fluctuations created by pistons flying around at 15,000 rpm--90 percent of the part numbers in the '03 R6 engine are new. Cams dial in higher lift, and valve springs are stiffened to match.YAMAHA YZF-R6 2003