Its like stumbling upon Alladins Villiers cave this lot
Part 6 - The Sixties
Engines were still being developed in the sixties, the A series was the greatest beneficiary in this period. The 32A was developed as a trials engine, the 33A became the 34A, still a scrambles unit and the 35A was supplied to Bond for use in their three wheelers. The 36A was very similar to the 33A and 34A engines. A wide range of 4 speed gearbox variations were available and, a new departure, Villiers offered the 33A, 34A and 36A with Amal carburettors. An Amal 389/39 was fitted to them. Villiers S25/5 carburettors were used on the 32A and 35A engines. Compression ratios were 7.4:l on the 35A, 7.9:1 on the 32A and 12:1 on the 34A and 36A engines.
The final development of these engines was announced in 1965 when the 37A came on the scene. This had many of the features of the 32A but used a lightweight crankshaft, gearbox shell and end cover and was fitted with a special wide ratio gear cluster. As these A engines were similar they could be changed for events as required by the rider and they were well used in events in many parts of the world. I will comment upon results later.
The 3L, already mentioned in Part 5 was introduced in 1960 and the 4T in 1963. This was very similar to the 2T, giving 249cc capacity but was given a higher compression ratio of 8.75:1 as against the 8.2:1 of the earlier units. Three variations were offered, the 4T for use in motor cycles and the 4T/SK and 4T/SKR for use in scooters and three wheelers. The 4T had an 18 tooth final sprocket and the others a 17 tooth sprocket. All used the Villiers S25 carburettor. They were recorded as giving over 17 brake horse power at 6,000rpm. The 4T used a Villiers flywheel magneto and the others had a Syba Dynastart fitted.
The engine I have left to be the last I detail is one that made some enthusiasts think that Villiers had taken on a new lease of life. They named it Star Maker (later changed to Starmaker). It was designed by Bernard Hooper and was originally intended to be for use in scrambles but was soon being used as a road racing engine. Various firms and individuals were adding their own tuning and Villiers, as always, took note of this and soon there were three variations available, a road racer and a trials unit in addition to the scrambles engine. The engine prefix indicates the variations offered on the engine and includes 757D for the standard scrambles engine, 490E for a road racing version, 834E a road racing engine with closer finning on the barrel and head, 871E a trials engine, 972E a standard road use engine fitted with 12 volt rectified lighting, 131F a trials engine with 6 volt direct lighting. The Starmaker engine had a bore and stroke of 68mm×68mm giving a capacity of 247cc. The compression ratio was varied, the road racer having 13:1, the scrambler 12:1 and the trials engine 8:1. Different gear ratios were used on each, road racer 2.21:1, 1.45:1, 1.2:1 and 1:1, scrambler 2.52:1, 1.66:1, 1.255:1 and 1:1, trials 3.5:1; 2.08:1; 1.375:1; and 1:1, and different carburettors and inlets were used: racer Amal 3 GP2 with a 1.5 inch choke, scrambler Amal 389 monoblock with a 1.375 inch choke, trials Villiers type S25 with a 1 inch choke.