Recreating the Roots of Royal Enfield

[Hugh Janus]

Gordon May, in period attire showing off Royal Enfield’s Project Origin, based on Royal Enfield’s first motorized bicycle prototype from 1901. (Royal Enfield/)

Does anything from the Industrial Age ever get “lost”? Centuries-old paintings, religious scrolls, famous correspondence; this stuff gets lost all the time. But it’s hard to think of anything mass-produced disappearing. There’s always blueprints, records, or technical specs. Right?

It’s been 122 years since Royal Enfield built its very first motorized bicycle prototype. But two world wars, two depressions, eight recessions, and a relocation to India meant this important piece of motorcycling history was somehow lost or destroyed.

Can you make this? One of the few surviving images of Royal Enfield’s first motorized bicycle prototypes. (Royal Enfield/)

Any company’s first prototype or production model is an obvious symbol of pride. But it also contains a company’s spiritual DNA. Case in point? A mile away from Royal Enfield North America’s Milwaukee headquarters stands another example of corporate pride, aka the Harley-Davidson Museum.

Gordon May felt Royal Enfield’s history was no different. As an author of books about Royal Enfield’s history and a member of the Royal Enfield brand team, May was recently appointed as Royal Enfield’s in-house historian. First off, how does one get this job?

“At a press event, our CEO mentioned that Royal Enfield’s heritage was so important they had an in-house historian. I realized he was talking about me.”

In-house historian Gordon May assembles a dragnet of clues as to how the prototype was built. (Royal Enfield/)

Royal Enfield’s upcoming 120-year anniversary sparked an idea. During a historical presentation about the upcoming 120th anniversary, May issued a challenge to the Royal Enfield engineering and design teams: Build a faithful, working replica of Royal Enfield’s first-ever motorized bicycle prototype. And do it without the benefit of any blueprints or technical drawings which, like the prototype itself, were long lost. Easy-peasy.

Armed with just a handful of black-and-white photographs, a tattered 1902 brochure, and a couple of illustrated news articles from 1901, a corps of volunteers formed. Enlistees from Royal Enfield UK joined forces with the Indian technical center, Harris Performance, and sundry experts from the vintage motorcycling community to recreate the oldest motorcycle from the oldest motorcycle manufacturer still active.

CAD drawings were crucial in turning guesswork and conjecture into technical information and blueprints. (Royal Enfield/)

May sums up the mission. “For us as a brand, to be able to show our origins and share them with the community around the world is really important.”

The lost prototype debuted at the Stanley Cycle Show in London in 1901. “Prototype” is a bit misleading. It was for sale, at 50 pounds sterling, or about 4,000 pounds or $5,200 in today’s money. It was put into production, but no factory records exist as to how many were made. May estimates that perhaps 200 may have been produced.

It featured a 239cc single-cylinder engine that put out roughly 1.75 hp, designed by Frenchman Jules Gobiet who worked closely with Royal Enfield’s co-founder and chief designer, Bob Walker Smith. The French were early leaders in engine design, with De Dion, Peugeot, Société Buchet, and Griffon mills found in many fledgling automobile and motorcycle designs. None other than Harley’s first V-twin, the Model 5-D, was inspired by a Griffon engine.

Whatever you do, don’t forget the oil. A detail of the 239cc single-cylinder engine with brass hand-operated oil pump on the right. (Royal Enfield/)
The Royal Enfield Project Origin frame begins to take shape. (Royal Enfield/)

Background aside, it was time to bring the past to life. Armed with piecemeal information, engineers set to work assembling educated guesses about 120-year-old technology.

“Our engineers understand disc brakes. They don’t understand drum brakes, let alone band brakes. They know overhead valves, not atmospheric inlets.”

Harris Performance helped create the chassis, but some of the prototype consists of existing period parts, such as the wheel rims, hubs, the band brakes and handlebars. But most often, parts were made in CAD with only old photographs to guide them. They did have one thing going for them. Owing to their rich bicycle history, frame construction was somewhat of a known.

Every book ever written about Royal Enfields (including May’s own) assumed the engine was a Belgian Minerva engine, but it turned out to be a copy of a Ducommun of Alsace engine. To build it, they used CNC machining on a single billet aluminum block to make the crankcase, while relying on a donor De Dion cylinder head. The cylinder sleeve remained cast iron.

Fabricator Ian Bain built the Project Origin tank (with three compartments) out of a single piece of brass. (Royal Enfield/)
A single, simple line drawing in a 1901 brochure was the only help in building the brass tank, here recreated in CAD. (Royal Enfield/)

You might think Project Origin unfairly benefits from recent advances in metallurgy. But despite the garden shed origins of many early motorcycle “manufacturers,” engine makers were often a separate enterprise. And they had access to good materials, CNC machining notwithstanding. May points out that most early engines were constructed of virgin steel, rather than steel derived from recycled metals.

Unit construction was a distant innovation on the horizon and with its horizontally split cases, the first Royal Enfield prototype wasn’t typical. The design kept oil from leaking on the front wheel, a safety feature to be sure. I ask May how they hid this amazing innovation from rival marque Triumph for more than 70 years? May gets the joke, but demurs.

“Actually, the Royal Enfield Bullet from 1931 also featured vertically split cases, so Triumph certainly wasn’t alone.”

To be fair, vertically split cases offer greater design flexibility for transmission placement. Horizontally split cases, though less prone to leaking, force designers to place the crankshaft and transmission shafts on the same plane where the halves meet.

A detail of the carburetor attached to the fuel portion of the brass tank. Note the bleed pipe (right side) coming from exhaust, to help warm the fuel-air mixture. (Royal Enfield/)

In 1901, few best practices or design orthodoxies existed yet. Royal Enfield had been making bicycles and assorted parts since 1882. Early motorized bicycles were just existing bicycle frames with an engine bolted on. What was the “best” way to do this? Only trial and error provided answers. Driving the rear wheel from a forward-mounted engine above the front wheel was an improvement over a front-driven wheel, which resulted in “side slip.” The original rawhide drive belt has been replaced with a modern rubber one.

So who gets to ride Project Origin? Only one man gets the nod; May himself. He points out it involves lots of operational awareness.

“That was a journey of discovery as well,” May dryly notes.

Although it has band brakes front and back, throttle control consists of pulling a handlebar lever that actuates valve lifters. Effectively, the motor always runs at max throttle, though the carburetor can be adjusted via a lever. Squeezing the valve-lifter lever opens the exhaust valves, thus eliminating the vacuum that draws fuel and air into the combustion chamber. Basically, you just “de-power” the engine to slow your roll.

The left side of the hand-built brass tank containing the trembler coil, oil tank, and fuel tank. (Royal Enfield/)
A period-correct motorized bicycle deserves a period-correct murky workshop. Project Origin patiently awaiting its closeup. (Royal Enfield/)

The tank may be the most impressive component. Made from a single piece of brass, it consists of three separate compartments holding the fuel, oil, battery, and tremblor coil, in place of a magneto. The only reason they know this is because they found an old ad from 1902 with a simple line drawing of the tank.

Period-correct work required period tools. They sourced and used period Victorian soldering irons to build the tank. Coil wiring was routed in brass tubes through the oil and fuel tank to reach the cylinder head. Baffles separate each compartment. It’s certainly a neat, tidy, and safe-ish design solution.

A small amount of fuel is added to the cylinder to help with starting. Horn is on the right, carb manifold is on the left. (Royal Enfield/)

Other engineering notables? The trembler coil offers fantastic combustion, since it basically generates a constant stream of spark. Also, a bleed pipe from the exhaust is routed next to the carburetor to help warm and atomize the air-fuel mixture. That’s assuming it starts at all. The carb is located below the engine, with 18 inches of upward inlet manifold. This makes for challenging starts on cold English or Milwaukee days.

“We’ve put towels in boiling water and wrapped them around the inlet to help start it.”

Now to address the question on everyone’s mind: Does it rip? May claims it develops speed nicely and corners well once under way.

“I’ve gone pretty fast around bends. It’s good, I feel confident in how it handles.”

So what’s the top speed?

“We had a car ahead filming my ride, and we easily hit 35 mph. I was urging him, ‘Faster, faster!’ since I didn’t know if I was going to make it up the next hill.”

Gordon May powering through a bucolic English town. He’s the only authorized rider for Project Origin. (Royal Enfield/)
Gordon May handling public relations duties and fielding questions via Zoom from Royal Enfield North America’s Milwaukee headquarters. (Royal Enfield/)

Oil must be injected every 10–15 minutes, as lubrication is total loss. May explains it uses Castrol, so it has “that wonderful smell.” The glass used in the oil pump had to be hand-blown, nicely matching the hand-operated pump.

“The first half-mile, you’ve got billowing smoke. Then it starts to run really cleanly and it’s beautiful. Then you start to get anxiety. There’s a tendency to over-oil things.”

The cost, risk, and complexities of early motorized bicycles clearly wasn’t much of a deterrent. Then as now, they were hooked. And 120 years later, the minimalist thrill and mastery of risk are still obvious. Royal Enfield’s Project Origin brings history to life in the best way possible. It’s smoke, clatter, and wide grins. Royal Enfield’s classic slogan says it all. “Pure motorcycling” indeed.

More than a village, it takes an international team of builders, engineers, and experts to recreate a 120-year-old motorcycle. (Royal Enfield/)

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