But they've had a reputation for belching out a fair bit of smoke and unburned fuel, a situation that just couldn't fly alongside tightening emissions regulations around the world, so they've fallen out of favour. But now there's a glimmer of hope. Earlier this month, Honda submitted a patent application for a brand new two stroke motor that uses direct fuel injection for a cleaner burn and better piston cooling. We may yet see a resurrection of the ring-dingers.

Uncovered by eagle-eyed patent hawks at Morebikes, the new patent describes a new two-stroke engine with a fuel injection system mounted on the back of the cylinder, pointing upwards toward the back wall of the cylinder bore. The injector is set to spray the fuel when the piston is near top dead center, so that unburned fuel won't get swept out with the exhaust gases, and the fuel is aimed such that the cylinder and piston can both be partially cooled as the fuel evaporates against them.

Honda believes this design can help eliminate some of the complexity of other injected two-stroke designs, helping bring the production and maintenance costs down and potentially making them relevant for manufacture again.