The 2006-model YZF-R6 received YCC-T electronic throttle control to smooth the response of its high-revving engine across the operating range. That engine also used two fuel injectors per cylinder: the main injector throughout the rev range, with a secondary injector joining it at medium and high rpm.
YCC-T reads the rider’s twist-grip input and passes it to the control unit. This calculates the required airflow and moves the throttle valves with a servomotor. Grip rotation therefore no longer determines valve opening through a mechanical ratio alone; data from other sensors also informs the adjustment.
The 2007-model YZF-R1 also used YCC-I. Here, a servomotor changes intake funnel length. The upper and lower sections normally connect; above specified engine-speed and throttle-opening thresholds, they separate so that only the shorter lower section acts as the intake duct. This helps match engine operation to different rpm ranges.
YCC-T regulates throttle valves; YCC-I changes intake geometry.