[1][2] Yamaha started development of the OX66 in 1984[1] as a design concept for a lightweight and compact Formula Two engine with a wide power band.

Unlike with a gear drive system, where incorrectly tightened cylinder heads can introduce backlash, a tensioner can be used to ensure the belt works optimally.

To decrease the diameter of the camshaft sprockets and make the engine more compact, a reduction gear train is used that indirectly connects the crankshaft to two separate timing belts, one per cylinder bank.

The fuel injection pump is driven by a belt connected to the left bank's intake camshaft.

In 1985, the OX66 was tested in two cars under actual competition conditions, driven by Geoff Lees and Keiji Matsumoto.

Alongside Ken Matsuura Racing Service, Tomei Engine and Ogawa Motor were also in charge of maintenance.

In that year's F2 championship, Lees won a total of four races, but lost the overall title to Satoru Nakajima.

Aguri Suzuki and Kaoru Iida drove for Yamaha in the 1987 Grand Champion Series, which still allowed F2-engined cars.