The engine in Yamaha FZ S V3.0 FI is a single-cylinder, 4-stroke, air-cooled, SOHC (Single Overhead Camshaft) engine. This type of engine is commonly found in motorcycles due to its simplicity and reliability. The single-cylinder design means that there is only one cylinder in the engine block, which makes the engine more compact and lighter. The air-cooled system is a simpler cooling system that relies on air flowing over the engine to dissipate heat, whereas liquid-cooled systems use a liquid coolant to transfer heat away from the engine. SOHC means that there is only one camshaft in the engine that operates both the intake and exhaust valves.