Bearing - gearbox main gear wheel bearing for Norton upright , Norton laydown and AMC laydown gearboxes including Commando. Also fits Triumph. 1-1/4" Norton upright and laydown boxes 1930? to 1972. Branded bearing: either Korean or Japanese.Original Part Number:9664; A2/316; N8011; 040098; - Norton Main gear wheel bearing57-0448 - Triumph high gear bearing to fit pre unit 4 Speed twins including 3T68-0023 - BSA A50 A65 A 75 4speed