2006 Yamaha YZF-R6, Compact, lightweight 67 x 42.5mm 599cc DOHC 16-valve liquid-cooled inline four-cylinder features titanium valves, 12.8:1 compression and compact combustion chambers to produce maximum power at 14,500 rpm and a rev ceiling of 17,500 rpm. YCCT Yamaha Chip Controlled Throttle uses a powerful ECU and multiple sensors to provide perfect, smooth engine response and optimal power whenever the throttle is twisted, under all conditions. Twin-injector fuel injection: shower-type injectors above each intake funnel help achieve optimum fuel atomization at high rpm.