Coming from a man preparing to clamber into the cockpit of a sleek machine called Jet Reaction, designed to travel at 400mph, it was a surprising admission. “I don’t really like going fast. It’s scary and bloody uncomfortable. Frankly, driving it is a pain in the arse.”

Still, if all goes to plan, Richard Brown will behind the controls of Jet Reaction later this year at the Bonneville salt flats in Utah, US, when he tries to break the two-wheeled land speed record. “No, it’s not about the thrill of speed at all,” says Brown, 50, an engineer from Oxfordshire, who makes his living buying and selling machine parts. “I’m prepared to drive it because it’s necessary but I don’t like it.”

What it is about for Brown is the engineering challenge of building a machine that goes that fast. “I’ve always been fascinated by propulsion and by how things work,” he said. “It’s the puzzling things out that really interests me, the solving problems.”

Brown is at a British equivalent to the American salt flats synonymous with land speed records this weekend, to tweak and test his machine. When the tide sweeps out at Pendine Sands in Carmarthenshire, south-west Wales, it leaves – as long as the wind is helpful – a long stretch of flat sand.

In 1924, Malcolm Campbell set a world land speed record of 146.16 mph here in his Sunbeam 350HP car, Blue Bird. Earlier this month, the actor Idris Elba hit 180.361mph on Pendine in a Bentley Continental GT Speed. This weekend speed fans descended to whizz along the beach on modern and vintage motorcycles and souped-up cars.

The Jet Reaction is a league above even those customised vehicles, it is propelled by the sort of engine more usually found driving a Sea King helicopter’s rotor blades. Brown redesigned that engine so it would provide the forward thrust needed. He built a bespoke jet pipe that could jink past the rear wheel and added an afterburner to give the extra kick needed. Stopping is another problem – first a parachute is released to slow it down, before a rear-wheel brake can bite.

Jet Reaction is Brown’s third attempt to make history. In 1999 he came tantalisingly close when he rode his rocket powered creation, the Gillette Mach 3 Challenger, to an officially recorded speed of 332.887mph – the fastest speed ever seen on two wheels at that time. Sadly, he was unable to complete a return run due to track conditions and so was not entitled to claim the Fédération Internationale de Motocyclisme record.

That machine was retired to the National Motorcycle Museum in the West Midlands and Brown set about creating an even faster version. Jet Reaction took four years to design and one to build at Brown’s workshop, from where he also runs his business. “It’s very much a part-time project. I have to earn a living,” he said. The charm of the venture lies in its cheerful amateur nature. Brown is helped by mates and speed enthusiasts – who rejoice in nicknames such as Ginge and Mutley. They give up their time for free; his wife Paula, was on the beach this weekend, providing support – with a flask of tea, and sandwiches.

Brown is reluctant to discuss how much the project has cost. “I’d rather not think about it,” he said. His PR puts the price of the machine at about £100,000 but that does not take into account his or others’ time. The contrast between Brown’s efforts and those of the Bloodhound SSC team who are based just down the coast at Avonmouth, near Bristol, is striking. Brown estimates the Bloodhound project – an attempt to break the 1,000mph mark - would swallow up his budget within two days.

While Bloodhound attracts blue-chip sponsors, no high-profile company has come forward to back Brown. That may be largely because Brown, as well as being a reluctant speed fiend, does not much like talking about or promoting his efforts. Nor, for that matter, does he have an exciting nickname. Unlike Rocky “The Rocket Man” Robinson, from California, who holds the current record – 376.363mph. Robinson and the machine he pilots – Top 1 Ack Attack – will also be in Utah in September, aiming to break the 400mph mark.

Because Pendine tends to be windier and wobblier (“a bit squirmy” is how Brown puts it) than Bonneville, Jet Reaction was being tested on three wheels this weekend. In a few months, the two back wheels will be removed to be replaced by one, Brown will don his bright blue, flame retardant suit and boots, climb into the cockpit, throttle up, hit a button and, hopefully, zoom into the record books.