PAPER CLAMP PIN CLIP
Some piston pin clips can be a bear to install. If not supported right, the first one will push in too far or can be hard to seat. I lube and install the piston pin and then use the arm or wing of a paper clamp to keep the pin in place while I push in and seat the first clip. These are available in various sizes, depending on the size of the clamp. Once removed from the clamp, it may need to be spread apart to fit the diameter of the hole. Once in and with a piston pin resting against it, it will not fall out, but is easily removed when you turn things over to install the second side clip. I keep a magnet hanging above the work bench that holds a few different sizes.