Harry was born in Exeter, on 21st August 1897, into a comfortable middle class family _ his father, Henry John Weslake was a director of Willey & Co.. He had a brother ten years his senior, and a sister who had died before he was born. His maternal grandfather named Lavis had been a boat builder in Exmouth, a name that is still connected with the industry to this day. Harry's first home was Clyde House, Princes Street, St Thomas, an area of comfortable, middle class housing from which, his father could walk to work. The young Harry was sent to Exeter School where he found a liking for sport, rather than study, and he soon learnt that physical fitness was one way of keeping the school bully at bay.

As a schoolboy, he acquired a bicycle, but quickly craved after a motor cycle. To this end he designed a system where a motor would drive a third wheel next to the rear wheel on his bicycle, rather like a side-car. His father was not impressed by the design which was not developed; a couple of years later, the Wall Autowheel was marketed, forcing his father to apologise for his lack of faith in Harry's original concept.

First motorcycle ride

In 1912, at the age of fifteen, using his pocket money, Harry applied for his first driving licence, and immediately hired a Swiss Motosacoche motorcycle from the St Thomas' Motor Cycle and Cycle Car Garage, Alphington Street, run by Phillip Pike. He was serious about his first motorised venture, acquiring a pair of goggles, and a belted black macintosh, 'de riguer' for a budding speed king. Out on the open road, he was spotted by a friend of his mother, who immediately reported his adventure. The Chief Constable, a family friend, was informed, and soon every constable around Exeter was told to keep a lookout for the speeding Harry. While enjoying his ride through Kenford, Harry was stopped by a policeman with the words, "Be you young master Weslake. Go on home, your mother wants 'ee." He decided to get the best out of a truncated tour by taking the long way home. Near Starcross, the drive belt broke, and having no tools, he was forced to return with the motorcycle by train, and a ticking off, in which he defended himself with some passion.

His father managed had Harry apprenticed to Willey and Co with the aim of progressing through all the departments, learning the ways of the tool room, drawing office, foundry and engineering shop. This was a good training for what would be his future career, but first there was the little matter of getting to work, which for Harry, meant acquiring a motorcycle of his own. His parents must have realised that they could not prevent the lad, and after some pressure, they agreed that he could have a motorcycle. A Rudge Multi, which in 1915 cost £58 15s, was ordered from the Rudge dealer in Sidwell Street – when the mechanic delivered the machine, Harry's mother enquired why was he pushing it and not riding it, to which he replied that it was too fast for him, and that Harry was the only one who could ride it with any skill, having had a test ride earlier. Soon, Harry gained a reputation as a skilled motorcyclist, even having an impromptu race with a local, Reg Holloway, who had competed in the 1913 Senior TT.

Harry organised and entered many hill climbs around the Exe Valley and Dartmoor. The Rudge was an ideal machine as it had a multi-gear which allowed an almost continuously variable ratio of gearing for selection. However, the difference between the top and bottom gear ratio was not great, so Harry set to work to fit an NSU two-speed gear to the crankshaft, allowing the gear range to be doubled. With this gearing he arranged for a hill climb at Pepperton Lane, Moretonhampstead, one of the more difficult hills in the area. His Rudge sailed up the 1:2.5 gradient and around the two extreme S bends without any difficulty, only to have his pride pricked when the local AA man ascended the same hill, with ease, on his Triumph, a route he often undertook for his work.

A better combustion

By this time, Harry Weslake was becoming an expert in the workings of his motorcycle, and was only too aware of its shortcomings. The Rudge had a carburettor known as a Senspray, that injected fuel somewhat like a scent spray – it was a better arrangement than other carburettors, but open for improvement. Using his engineering knowledge from Willeys, Harry improved upon the design, leading to better fuel economy and a joint patent taken out with his father in 1918.

At the outbreak of war, the 17 year old Harry tried to enlist with the 7th Devons, but his prior arrangement with Willeys as an apprentice saw him quickly returned to the company. The next year he joined the Royal Flying Corps, and was posted to Hastings as a cadet pilot. The training required attending lectures in the working of the combustion engine, an area in which he was often ahead of his instructors. He so impressed a corporal instructor that he was taken to see the Chief Instructor, Major McClure, who was also impressed enough that he asked Harry to design and build two carburettors for testing on aero-engines. The testing interrupted a concert in the Sergeants Mess, causing some annoyance – the next day Harry's test engine started before all the others, proving its sound design. Harry was discharged from the RAF in 1919 to return to civilian life. By 1921, the family had moved into Franklyn House, Cowick Lane and soon after his mother died of cancer, followed by his father with the same disease.

Weslake Research and Development was founded by Harry Weslake, a cylinder head specialist who had been instrumental in modifying the side valve Standard engine used in the first SS (later to become Jaguar) Sports Car. He also designed the cylinder head for the overhead valve version of the Morris series A engine that was used in the Morris 1000 and the Mini. He was involved in the design of every Jaguar engine up to and including the V12 of the early 1970´s. He also designed the Straight-4s engines for the 1958 Vanwall Formula One Grand Prix Car, an engine that was using a lot of technology and experience from a single-cylinder Norton motorcycle engine. The Vanwall car went on to win the 1958 F1 constructors cup.

In 1966 Dan Gurney commissioned Weslake Engineering to build an Aubrey Woods designed 3.0 litre V12 Formula One engine for his 1967 Eagle T1G. Their efforts produced a V12 that was smooth and powerful. Gurney won the Race of Champions at Brands Hatch, a non-championship event, and the 1967 Belgian Grand Prix with the Eagle-Weslake V12 engine. Weslake now have two divisions. Weslake Air services is run by Harry Weslakes stepson. Weslake Air Services designs and takes to prototype stage aircraft engines especially diesel-powered engines as used in airships and light aircraft. They are at the leading edge of design and world leaders in this field.

The main Weslake Factory now concentrate on specialized aero engine design and development however following increasing requests for services covering Weslake past projects in particular on the Motorsport side The Weslake Heritage has been launched to look after their needs.