Suzuki Dual Throttle Valve: The Hayabusa engine is fitted with tapered, 44mm double-barrel Suzuki Dual Throt tle Valve (SDTV) throt tle bodies. Unlike conventional fuel-injection systems, the SDTV system has two butterfly valves in each throttle body barrel. The rider controls the primary valve via a throttle grip, and the engine management system automatically controls the secondary valve, opening it incrementally to maintain optimum intake charge velocity based on engine rpm, gear position and primary valve opening. This precise, carefully controlled system improves combustion efficiency and makes throttle response feel more natural to the rider.