1961 AJS Model 31 CSR 'Thruxton' (650cc) in Weybridge, Surrey for sale

Phone: For sale by auction on Saturday 06 June 2015 with Historics at Brooklands, Brooklands Motor Racing Circuit, Weybridge, Surrey, Call 0 The AJS Model 31 was made by Associated Motorcycles at the former Matchless works in Plumstead, London. Developed in 1958 specifically to capture the potentially lucrative US market, the last Model 31 was produced in 1966. The AJS Model 31 was designed by Phil Walker, AMC knew that it had to be a 650cc but wanted to use as many cycle parts from the Model 11 as possible. The meant developing a new crankshaft and primary chain case which also provided the opportunity to add a Lucas alternator. In 1959 the Model 31 was redesigned and modernised as the De Luxe with a new full cradle tubular duplex frame and a new cylinder head. Capable of 100mph performance, it was no surprice that motorsport beckoned. The AJS Model 31 CSR designation officially stood for Competition/Sport/Road with its distinctive 2 into 1 'Siamese' exhaust system and upgraded camshafts, the CSR was a high performance motorcycle but still prone to leaks and vibration. The factory diverted Chief Engineer Jack Williams from AJS 7R development to address the problems and modify the bikes for racing with the result that Ron Langston and Don Chapman won the prestigious Thruxton 500 long distance endurance race on the AJS Model 31. With matching frame and engine numbers, this example is a very special machine indeed. Ten engines were diverted from the production line and sent to the competitions department. One blew-up leaving nine tuned motors of which three were sent, in bikes, to the Isle of Man for exclusive use by the marshals at the TT and this is thought to be one of those three. Despite an incorrect tank fitted, the bike remains in good order and is reported to run well, the last owner using her regularly and for many years.