The Stevens family built their first V-twin more than a century ago, when AJS were still firmly rooted in Wolverhampton. Introduced in 1912, the sidevalve Model D initially used a 631 cc motor with a two-speed gearbox, then became a 698cc with a three-speed box, then 748cc for 1914. From 1921 and for the rest of the Twenties the engine size settled at 799cc which provided sufficient propulsion for sidecar duties.
These V-twins weren't sports bikes, of course; that role was fulfilled by the firm's small singles which would evolve into the famous Big Port racers. Rather, the heavyweights offered reliable family transport which would propel mum, dad and offspring at 35-40mph. Titch Allen tested one such 799cc outfit in the 1970s and found it loud and vibratory -'the sound effect is like that of a combine harvester'- but with adequate performance for its period, and above-average brakes and easy steering. The multi-plate but single spring clutch would slip and drag, while crash-sliding gear selection was awkward and the gears were prone to failure. Access to the valve gear for adjustment was easy, however, and the V-twin was overall'a
