Useful, reliable commuters, loose handling, drum brakes fade. Engines run to 30-40k when small-end and bore become troublesome, but with a rebuilt top end can break through 50k mark. A dead condensor can make starting difficult. Also check for chassis rot at this age. B120 had easier life as commuter, many A100’s ruined by learners.
A100: 1968-80, 99cc t/s single, 9hp, 60mph, 90mpg, 190lb B120 1971-77, 118cc t/s single, 10hp, 65mph, 100mpg, 210lb