Voldos,

There is no bearings no the conecting rod.

Sellaplane,

The YS engines are supercharged, and no internal combustion engine of that displacement has the torque at low or medium RPM's as the YS, ussually the YS 170 is an expensive engine that goes in much more expensive airframes, so fuel cost is not an issue if you can afford the equipment, and power to weight, no gas engine come close to the YS.

Regards