Four Stroke F70. One Step Ahead.
Yamaha F70 is a further development of the F60, sharing the same displacement and stroke. The engine is lighter than any competitive four stroke or direct injected two stroke motor in the 70 – 75 horsepower class. The F70 achieves this by its unique four valves per cylinder design activated by a single overhead camshaft rather than the conventional dual camshaft design for 16 valve engines. This reduces the weight that would result from having an extra camshaft and the components that go with it.
For a remarkably light engine, the F70 punches well above its weight. Four valves per cylinder have dramatically increased this engines volumetric efficiency – the efficiency with which the engine can draw fuel and air in and push exhaust out of the cylinders. Increasing this efficiency means the F70 is able to run at a higher RPM with the max operating RPM being increased to 6300 RPM. The resulting top end performance will be great for boaters who want to get to their favourite spot first – and who doesn’t?