I started my biking career on early '70s Japanese two strokes and here are a couple of interesting prototypes of the time. In 1971 both Yamaha & Kawasaki showed 750cc four cylinder water cooled two strokes. These would have taken on the Suzuki GT750 in the big stroker market. Neither made it into production. Maybe because of pollution or fuel crisis worries. Kawasaki were already developing the Z1 at this time and the Yamaha seems to have been the basis for the TZ700/750 racers.
|Kawasaki 750 Square Four|
|Bike has family resemblance to early Z1|
|Early use of reed valves. Also looks like fuel injection.|