[_yb2s]

Must have been two stroke, 4 stroke motors are too large and heavy for an application like that.

[Epa095]

According to Wikipedia

> The engine was an air-cooled, 4-stroke, 155 cc engine over the front wheel

https://en.wikipedia.org/wiki/Autoped

[_yb2s]

Guess I was wrong, that’s a shocking engineering choice, that engine looks massive and heavy. A four stroke engine is about twice the weight and size for the same power output, but much more fuel efficient.

[gerdesj]

"Fuel efficient" - that's probably why. If the fuel efficiency more than off sets the additional weight, for range then four stroke might be indicated. There are lots of other factors to consider.

[_yb2s]

Four stroke engines are also quieter, last longer, and have lower emissions, but cost a lot more to make as they are much more complex.

[SR2Z]

I guess this is an old engine, but it's bizarre to me that fuel efficiency could be a factor for something this slow and light.

[saaaaaam]

Presumably carrying fuel on the device was a consideration so greater fuel efficiency helps reduce the amount of petrol you’re lugging around.

[_yb2s]

A major factor if you actually are using it to get anywhere, because it’s likely not practical to carry more than a liter or so of fuel.