upside-down motor 2 liter 3 cyl. air-cooled

[Fire-medic]

http://thekneeslider.com/archives/2010/10/11/nembo-motociclette-inverted-3-cylinder-super-32-rovescio-motorcycle-engine/

OK ya gotta read about this for yourself. This website always has a lot of interesting gearhead stuff for bikers.

 

[RaWarrior]

That's really interesting....I've seen inverted 2 cycles before, but never a 4 stroke. Even with a dry sump system there must be some wild oil control systems in there to keep it from "pooling" into the pistons....normally dry sumps aren't really "dry" and have a scavenge pump at the bottom that just sends it to an external oil box.

 

[Saml01]

Awesome concept but I don't know if its worth the complexity.

If you want to talk about an engine worth the time and effort its this:
http://en.wikipedia.org/wiki/MotoCzysz

 

[Fire-medic]

Aeromotive engines used the "upside-down layout" successfully in some of the most successful WW2 era planes.

 

[texmax]

Aeromotive engines used the "upside-down layout" successfully in some of the most successful WW2 era planes.

True, but they had to spin the prop by hand a few revolutions to evacuate the oil from the cylinder or risk blowing the jug off the crankcase. Thats why radials smoke for a bit on startup.