A ball stop valve (10) allows liquid to enter a reciprocating piston pump when internal suction is great enough to raise the ball (13) and create a space between the ball (13) and a seat (9). This invention allows the user to easily insert or remove rings (15) into the ball inlet valve, either above or below the ball (13), so that the space between the ball (13) and the seat (9) can be adjusted. The valve (10) is easily accessible to the user and all components of the ball valve (10) are removable.