The cross-plane crankshaft technology is something that you can see on the Yamaha R1. This crankshaft reduces inertia torque, that is created by the engine, to a minimum.
A conventional flat-plane crank features all of its crank-pins in the same plane along with two inner ones which are 180 degrees from the other two outer ones. The outer ones move up and down together just like the inner pistons. This configuration generates what we call inertial torque.
On the Yamaha’s cross-plane crankshaft the crankpins are distributed at 90 degrees to each other around the crankshaft. This means that when one piston is slowing down another is speeding up. At no point do these pistons stop together, unlike in a flat-plane crank. Check it out!