N15CS swinging arm

The N15CS has a swinging that is the same as the AMC frames. The 1963 Atlas Scramblers had two cotter pins and then this was changed to just the one in January 1964. This is a cotter pin and not a bolt and it has a bevel on it, so it has to be in place before the swinging arm spindle is removed. It has a nut and a washer when it is in place in the swinging arm. The spindle will have to be pushed out, and then the cotter pin will slide out. Your N15CS will be after 1964 so therefore it will only have the one cotter pin. The spindle may need to be heated to remove it, but it should have been filled with oil, but that can leak out due to there only being two, fibre type seals to keep the oil in. Do not attempt to remove that cotter pin while the swinging arm spindle is still in place, as it will be impossible for it to come out, unless that spindle has been removed. The swinging arm when you fit a new one, the oil cavity is filled with SAE 140 oil. The two steel sleeves that hold the spindle in the swinging, have two phospher bronze bushes inside, and they were only sold as the complete units. Try AMC Classic Spares for all the new parts. You will require two paper washers for the end plates, as well as the two fibre seals that fit on the out side of the swingling arm spindle. These bushes used to be or may still are of the oil light type. They had to be soaked in oil over night before being fitted. These bushes will have to be reamed to get them to fit the new swinging arm spindle, as they compress when fitted into the swinging arm assembly. 

The Triumph twins had a puller tool to remove their swinging arm pivot tubes, so you may be able to borrow one for your N15CS swinging arm.