Are you wanting a way to compress the spring so you can take the rotor belt of the pulleys? If so there, is a tool for that. A piece of flat steel that goes over the end, and two long bolts that pull the pulley open. If you also have the drive pulley open, the belt can be taken off. Would do the same thing if you blew the rotor belt and had to replace it. Alternatively, we have used a couple pieces of 2x4 cut into a "V" and hammered them in to the pulley to open it up.