What is crankshaft offset? I have been reading about Honda technology online book and found this picture that explains about it.
Based on the diagram, it is easy to understand how crankshaft offset works. As the name suggests, the crankshaft position which usually placed directly below center the piston are now placed ‘offset’ from the center. What happens is that the power stroke in every combustion that burns inside the chamber are now transferred directly to the crankshaft from the piston.
The benefit of this crankshaft offset method is that less friction will occur from the movement of the piston when it moves from Top Dead Center (TDC) to Bottom Dead Center (BDC) since all the movement are concentrated to the connecting and crankshaft, not to the side of the cylinder block.
Reliability of the engine are now increased since the all the section of the connecting rod takes the abuse of the power stroke, not just the top or bottom part.
With this benefit, it is easy to see an engine that is fitted with crankshaft offset will have more power and better reliability.
The only downside of this method is just the engine casing needs to a little larger to accomodate the offset crankshaft.