Rear chain, 520, 5/8 x 1/4 in [actual dimensions 5/8inch x 0.255 inch] , 91pitch, Renold Synergy with joiner. Max pin length=16mm. The original chain fitted to Nortons. 88P = ES2: 1949/51 89P = 18: 1948/53. 19R: 1954/55. 19S: 1954/58. Model 7: 1948/51 90P = Big 4; 16H: 1934/45; 1946/7; 1949/54 . ES2: 1946/7; 1949/51; 1952/53; 1954/56. Dominator 77: 1957. 91P = Big 4; 16H: 1948. 18: 1934/45; ES2: 1946/47. 50: 1956/58; Model 7: 1952/55. Inter 40: 1948/51. Inter 30: 1946/51 97P = Inter 40; Inter 30: 1954-55. 50: 1963. Dominator 88: 1961-64. Dominator 99: 1956-57. Dominator 650: 1961-64. 98P = Dominator 88: 1953-58. ES2: 1963. Dominator 99: 1961-62. Note: Use any other chain on a Norton and risk wearing away the primary case, chain guard and gearbox shell. Renold Synergy chain lasts up to 6 times the life of other brands see Renold synergy website
