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The Villiers Engineering Co. Ltd.


by John Favill

The Villiers Starmaker engine and transmission unit was introduced early in 1963. The intent was to make available to motorcycle manufacturers an engine and transmission producing the performance level needed to compete in the motorcycle sport known at the time as Scrambling, at International Level. The engine had capacity of 250cc having a specific power output of 100 bhp per litre.

The engine and transmission unit that carried the name Starmaker represented a departure from the traditional method of product identification used by the company. For many years the company had resisted using names for company products since the early days, when the bicycle known as the "Sunbeam Cub" was produced by the company. 

When Villiers began to manufacture internal combustion engines in 1912 a code system of a combination of numbers and letters had begun to be used to describe the type of engine and  engine capacity, and this had become the traditional method of product identification.  

In 1963 this new engine and transmission initially was intended for use in the type of motorcycle racing known as Scrambling, although other applications were being considered.

Very soon after the Starmaker was made available, the controlling body of the sport decided that the name Scrambling did not translate easily into other languages. To overcome this difficulty and to adopt a name that  reflected the increasing interest in the specialized motorcycle racing throughout the world, soon after the Starmaker was introduced, the more modern and more universal name Moto-Cross was adopted.

The unit replaced similar engine power units made by the company, namely the 34A and 37A which in turn had evolved from the venerable 9E.

The units the Starmaker replaced had reached the limit of power development and performance, and it was considered that only a redesigned replacement would be able to meet the forecasts of the needs of the market in the future of moto-cross racing that rapidly was becoming an international motorcycling sport.

The responsibility for the design of the Starmaker was given to two designers employed by the company; Bernard Hooper, a two stroke engine design specialist and John Favill (the author) who had developed a design specialization in gears and transmissions.

Motorcycle companies that purchased the Starmaker included DMW (a Sedgley company), Greeves, Cotton, James, and DOT.

After the introduction of the engine and transmission assembly to the motorcycling world, one of the developments soon after the introduction to the Moto-Cross application, was the use for road racing. The engine and transmission unit enabled race competitive road racing motorcycles to be made available at a relatively low cost.  The 4 speed gearbox was provided with close ratios but in addition, a specially designed six speed gearbox was made available. This road racing version of the unit was provided with a tachometer drive, plus an attachment to the timing side of the crankshaft that carried the ignition points in a separate bearing support that provided for better spark control for the ignition system at the higher engine speeds used for road racing. The developed power output was increased to 32 BHP at 7500 rpm.  (128 BHP per litre).

Motorcycles powered by the road racing version of the engine and transmission did very well on the racing circuits in the UK both for Moto-Cross and Road Racing, but the most outstanding year occurred in 1966. A Villiers built road racing motorcycle was ridden by Peter Inchley, (an experienced rider employed by the company for motorcycle development) to 3rd place in the Isle Of Man TT race for 250cc machines. This was the first time for 16 years that a British machine had finished in the first three and the first time a single cylinder machine had lapped the TT course at an average speed of over 90 mph. ( 91.43 mph) The only machines to beat the Starmaker were special multi-cylinder works machines made by Honda.

The third application for the Starmaker engine was for what was known as Trials, represented by such competitions as the famous Scottish Six Days international event. Torque output of the engine was critical for this application coupled with reliable and instant engine response. A wide ratio gearbox was made available for this application, with the maximum power output of the engine set at 14 bhp at 5500 rpm.

The other application, although a relatively small quantity of engine were used, was for four wheel Formula IV car racing where the road racing version of the engine was used.

Technical Specification of the Starmaker engine and transmission

All versions of the Starmaker engine had a cast-in austenitic spun cast iron cylinder liner, the ports of which were machined and used to locate the shell moulded sand-cores of the cylinder, ensuring accuracy of casting at all times and consistency of engine performance.

On each model the piston had narrow rings and a large diameter piston pin. The crankshaft assembly had a thin section forged-steel connecting-rod running on a caged needle-roller big-end bearing. The road-racing and moto-cross engines had full circle cranks to help provide the high crankcase pressure required for these engines. The crankshaft was supported on two steel roller bearings, plus a needle-roller bearing on the drive side. At the time the caged needle roller bearing used in the big-end represented the limit of the technical know-how on this type of caged bearing application.  

The engine performance levels, particularly in the road racing application, provided valuable research information in the development of technical design know-how for big-end cage design that has now become common practice.

The clutch was the first application of the use of a diaphragm spring in a clutch to be used on a motorcycle. Diaphragm spring clutches have now become universally used on both motorcycles and cars. The clutch had two sintered bronze friction plates with one steel intermediate plate, pressure being applied by a diaphragm spring. Although the clutch had a very high spring pressure the natural mechanical advantage allowed by the diaphragm spring plus the scroll type release mechanism ensured light finger pressure at the handlebar lever.

The extremely robust gearbox had shafts and gears of nickel chrome steel

(B.S. En36B Specification). All splines were of involute form and the shafts and rotating gears were carried on needle roller bearings.

The magneto was of the energy-transfer type with energizing coils carried in the stator plate, and transferring current to a separate encapsulated coil, which could be mounted on the motorcycle frame. Trials engines had a 6 volt direct current lighting system.

Drawings of recommended exhaust systems for each engine application were available, together with information on their effect on power and torque curves. Road racing units were provided with a tachometer mounting and an independent bearing support and self contained drive system that carried the points for the ignition system.


Road Racing



Compression ratio




Power rating

32 bhp @ 7500 rpm

25 bhp @ 6000 rpm

14 bhp @ 5500 rpm

Gear ratios 4 speed

2.21, 1.45, 1.2, 1 to 1

2.5, 1.66, 1.25, 1 to 1

3.5, 2.08, 1.375, 1 to 1

Gear ratios 6 speed

2.5, 1.9, 1.51 and
1.25, 1.09, 1 to 1



Amal 3GP2

Amal 389 monobloc

Villiers S25

Choke size

1.1/2 in (34 mm)

1.3/16 in (30 mm)

1.0 in (25 mm)

The cylinder bore and stroke was 68mm for all engine versions.

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