To pull it off you need a puller with the two bolts. In my 51 I had to raise the front of the motor a bit to get clearance. To put it back on you simply drive it on with a big heavy hammer. I use a large pipe nipple to interface with the pulley. One important thing is to measure the distance between the pulley and the front cover before you remove it. That way you will know when it is seated all the way when you are installing it.
