The invention discloses a low-noise valve rocker assembly of a motorcycle engine. The low-noise valve rocker assembly comprises a rocker which is assembled on a rockshaft of a cylinder head and a torsion spring which applies preload to the rocker, wherein the rocker includes a left side surface and a right side surface and the torsion spring includes a spiral section. A spring hook at one end of the torsion spring which is a rocking end is connected with the rocker in a lap joint mode, and a spring hook at the other end of the torsion spring which is a fixed end is connected with the cylinder head in a lap joint mode. The spiral section of the torsion spring is positioned on the left side surface or the right side surface of the rocker, and the rocking end of the torsion spring crosses the left side surface or the right side surface of the rocker to be connected with the rocker in a lap joint mode. The rocking end and the spiral section of the torsion spring are respectively positioned on the left side surface and the right side surface of the rocker, so that axial component force which is generated by the moving torsion spring to enable the rocker to move axially is avoided, abnormal sound produced due to the fact that the axially-moving rocker knocks the cylinder head is eliminated, loosening and position changing of the torsion spring and the rocker due to rocker forging die difference, torsion spring manufacturing error and the like cannot occur, and the firmly connection of the torsion spring and the rocker enables the rocker to run more steadily and quietly.