If the supply is normal to a radial piston motor, but it runs slower than normal, what should you check first?

In the scenario described, where a radial piston motor is receiving normal supply but is running slower than expected, the first step should indeed involve checking the condition of the valve. The valve plays a crucial role in regulating the flow and pressure of the hydraulic fluid directed to the motor. If the valve is malfunctioning or partially obstructed, it can restrict the adequate flow of fluid necessary for the motor to operate efficiently, leading to decreased speed even when the supply pressure appears normal.

Inspecting the valve for blockages, leaks, or other performance issues can reveal whether it is adequately allowing fluid to pass through. A poor valve condition can significantly impact the motor's performance, as it directly controls the hydraulic force applied to drive the pistons within the motor.

While it is also important to consider the condition of the hydraulic fluid, the transmission speed, and the motor size, these factors would typically be assessed after ensuring that the valve is functioning properly. If the valve is obstructed or damaged, addressing that issue could resolve the reduced motor speed without needing to delve into the other aspects.