I think of it as absolutely normal if you raise the rear wheel of a bike from the ground and start the engine with the bike in neutral that the rear wheel will rotate as the movement of the fluid in the gearbox transmits the drive from one shaft to another when there is no load on the wheel
Oil of the correct type is very efficient at transmitting drive as is used in a fluid coupling or a torque convertor although these devices are designed to use oil being rotated to transmit drive
Brian
Oil of the correct type is very efficient at transmitting drive as is used in a fluid coupling or a torque convertor although these devices are designed to use oil being rotated to transmit drive
Brian