MOPED ARMY

You can at this very moment buy two-strokes which have sealed crankcases, and which inject air-fuel mixture into the cylinder. Mercury Outboards is one. This could be improved on by by injecting air into the cylinder as the piston recedes from detonation, this would push the exhuast gasses out, and then on the piston's up stroke fuel could be injected, the air already in the cylinder mixing with the fuel, and detonating every stroke.

Cool - see, now answers to these types of questions all seem to come from non-motorbike sources - it's always an outboard or a marine diesel or a snowmobile that uses avant-garde two-stroke tech.

Zizz, where does the oil come in to the Mercury outboard though?

Also, if you push air into the cylinder to clear out the exhaust gasses (say, in advance of a squirt of fuel/air mixture) wouldn't you need an exhaust pipe that is just a straight draw? Or, does the squirt of air you're thinking about somehow counter any backpressure from the exhaust?

Even the perfectly straight, baffled exhausts on my '66 Puch (two of them - hooray for twingles again!) do create some backpressure, though I don't think it's really by design.

I think that the air squirt (which would only work with fuel injection, like you mentioned) might benefit cleanliness at the cost of efficiency, and I still wonder about a better way to oil these engines.

air would be a pain to shoot out of an injector that also did oil but doable

but to vary witch one was shooting u would have to have switches and valves set up to an air injector and oil injector that came out of the same nozel and the oil probably isn't light enuf to make a mist its to dense

Zeke - there is no need to inject oil .. the oil is sealed in the crankcase as with a four stroke .. there is no need for valves as the engine would work much like a conventional two stroke instead of the upstroke sucking gas, air, oil in the injector would shoot the gas and air in .. that's how diesel fuel injectors work .. they shoot it in. But diesel is four stroke .. this is two stroke .. but it could be made to one stroke .. a detonation at the peak of every upstroke.

How did we go off topic in a sort of off topic post?

The air-injector idea would probably necessitate just that - an air injector. That's possible, as is an oil injector, as is fuel-injection. It seems that what we have concluded is that the suitably-minded engineer can choose to build an anything-injector, and then use the various devices to time every aspect of engine performance. Well... that's kind of a cool idea too.

My favorite line in this topic so far is what I believe is a mis-type: "...but it could be made to one stroke..."

I think that only firearms are "one-stroke."

A detonation at the peak of every "upstroke" is a "two-stroke" engine (there's an upstroke and a downstroke).