Restoration guide
01 Engine
The aluminium crankcase housed a built-up crank assembly with substantial flywheels and an uncaged roller big-end for the steel con-rod. Pre-1931 models had a single drive side roller bearing and a self-aligning ball race on the timing side. This arrangement was superseded by a roller main bearing each side supplemented with an e drive side ball journal. Classic Norton dimensions of 100mm stroke and a 79mm piston gave a swept volume of 490cc. The timing chest contained individual gear-driven camshafts and, after 1930, the drive to a gear-type oil pump as
