TIMELINE: M SERIES & MORE
1931: EUGENE GOODMAN experiments with the Model M. Intended to be cheaper than the cammy K-series, it was a 348cc sidevalve which proved too slow for Veloce’s customers 1934: MAC introduced with longer 96mm stroke, giving 349cc. It output 14bhp at 5000rpm and reached 70mph 1937: AUTO ADVANCE / retard ignition timing introduced on all three M models 1948: DOWTY OLEOMATIC forks replace Webb girders. Front brake on MOV and MAC increased to 7”. MOV (total production c4500) and MSS discontinued at the end of the year 1952: SWINGING ARM rear suspension arrives, with twin WoodheadMonroe shocks, revised gearbox, new frame, dual seat and fuel/oil tanks 1955: A SPRING-FRAME alloy-engine MAC (15bhp at 5500rpm) was speed tested and reached 79mph 1958: VOLTAGE REGULATOR relocated to under the saddle. Venom/Viper oil tanks and various brackets strengthened 1960: MAC DISCONTINUED: production totalled c25,000 over 27 years. Clubman models launched for production / endurance racing 1964: CUT-PRICE ‘special’ editions of Viper and Venom introduced 1967: MARK II versions of Clubman models feature 2ls front brake and other high performance components from the Thruxton 1970: FINAL THRUXTONS use Amal concentric carbs. Motorcycle production draws to a close
1933: THE HIGH-CAM engine arrived as the 68mm x 68.5mm 248cc MOV (type M, overhead valve) with enclosed valvegear and geardriven cams. It output 12bhp at 5000rpm and reached 67mph
1935: MSS introduced with bigger 81mm bore, giving 495cc. It output 28bhp at 5000rpm and reached 80mph
1946: THE FIRST peacetime production machine built at Hall Green was a 350 MAC in March
1951: HYDRAULIC FRONT forks replace the air-assisted Dowty setup. Significant engine update mid-year: alloy cylinder and barrel, improved lubrication, higher compression, revised cams
1954: MSS REINTRODUCED with an 86mm x 86mm all-alloy engine giving 499cc in a springer frame. It output 27bhp at 5500rpm and reached 82mph
1956: VIPER 350 & VENOM 500 introduced; Viper much shorter stroke than MAC. Output 27bhp and 36bhp for 90mph and 102mph. MAC and MSS adopt Amal Monobloc carb and headlamp cowl
1959: ENGINE ENCLOSURES introduced on MSS, Viper and Venom
1961: VEELINE full fairing introduced. Venom Clubman Veeline maintains 100mph for 24 hours. New fuel tank for Clubman models. New high-output Miller dynamo
1965: ENGINE LUBRICATION modified to address wet sumping problems. Hand-built top-spec racing Thruxton 500 model introduced; 41bhp at 6200rpm and 115mph
1968: COIL IGNITION adopted. Final Viper built: production totalled c3700