Yamaha Genesis engine

Genesis is an engine design by the Yamaha Motor Corporation that debuted in the 1984 Yamaha FZ750.

The engine employs a DOHC design and uses five valves per cylinder with the cylinder group slanted forwards 45 degrees. It used downdraft carburetors instead of the side draft carburetors that were more common at that time.

The same engine is used in the Yamaha FZX700 model, a naked bike that was introduced in the USA in 1986. Originally the engine was 750cc [FZ750], but due to import restrictions 700cc was considerably cheaper, and therefore produced instead.

For more than ten years, until the 2007 model year, the Yamaha YZF-R1 used a 5-valve head and downdraft intake design.

The flexible design of the engine allowed Yamaha to use it on a variety of configurations, from sportbikes to high performance outboard engines.

When the engine was introduced, it used downdraft carburetors on the entry level Yamaha FZ750 sportbike, in a 20 valve configuration, using three intake valves and two exhaust valves per cylinder. The engine has evolved on the different motorcycles that Yamaha has used it for during the past several years to fill different kinds of markets. Applications ranged from the Supersport YZF-R6 and YZF-R1 models using electronic fuel injection with YCCT and YCCI to the less extreme but still powerful Yamaha FZ6 (4 valve per cylinder) and FZ1 Fazer line, using a simpler fuel injection designs but essentially the same basic engine design. The most significant changes made were the 4-valve per cylinder configuration and the crossplane crankshaft found on the YZF-R1 2009, along with the change of cylinder sleeves to steel for high precision and high temperature durability. Performance and reliability have made this engine design a total success over its long life.

Because of its high performance capacity (usually from 100 BHP 350 BHP), the engine has also been employed in various other uses such as gyroplanes and high power marine engines, making it an affordable solution for a high performance applications.

The engine is also used in a racecar championship in Norway called SevenRacing. It is a copy of Lotus Super Seven, and is produced by MK and Stuart Taylor.