The FZ16 features a negative pressure type Φ26mm carburetor. Unlike the conventional VM type carburetor, in which the throttle action forces action of the throttle valve (piston) to vary the surface area of the venturi, in a negative pressure type carburetor the throttle action opens and closes a butterfly valve. Then the force of the reciprocating negative pressure during the engine’s intake stroke moves the piston valve up and down to vary the fluctuations of the surface area of the venturi. This is the mechanism that supplies the amount of air-fuel mixture required by the engine.