Motorcycle engine

A motorcycle engine, comprising a crankcase, wherein the crankcase is provided with two cylinder pore channels, a combustion cylinder and a balancing cylinder are respectively connected at outer ends of the two cylinder pore channels, the combustion cylinder comprises a first cylinder and a first piston slidingly fitted inside the first cylinder, the balancing cylinder comprises a second cylinder and a second piston slidingly fitted inside the second cylinder, the second piston is provided with an air vent-penetrating from top to bottom, wherein a shaft axis of the combustion cylinder and a shaft axis of the balancing cylinder are arranged crosswise in a V shape, the second cylinder and an arrangement direction of the cylinder pore channel in which the second cylinder is located are arranged crosswise in an axial direction, and a lower end of the second cylinder is deviated toward a side where the first cylinder is located with respect to the arrangement direction of the cylinder pore channel in which the second cylinder is located.