British RAF Captain Charles Kenilworth Shepherd, or C.K., as he preferred, was 23 years old in 1919 when he swung a leg over his brand new Henderson Z-2-E four-cylinder motorcycle in New York and pointed his wheels in the direction of the setting sun. C.K wrote about his adventurous journey in 1922 with the release of Across America by Motor-Cycle, a tome that, some eight decades later, became a turning point in the life of Captain Mark Hunnibell. The connection between the two men hinges on Henderson motorcycles. When Mark was 21, in 1978, while poking around a dusty corner of his father’s Rehoboth, Massachusetts machine shop, he discovered pieces of a dismantled 1919 Henderson Z-2 four-cylinder motorcycle – an identical machine to C.K.’s, but without the optional electric lights and horn. An abandoned project, the Henderson had been neglected for years, and Mark asked if he could have the remains.

The Henderson Four on which C.K. Shepherd crossed the USA in 1919, documented in his book ‘Across America by Motorcycle’. [C.K. Shepherd]
Just what attracted Mark, who now lives in Yellow Springs, Ohio, to the machine is something of an enigma, as he had never spent any time riding a powered two-wheeler apart from a Honda moped. The Henderson, however, spoke to him, and his father gave him the project. It didn’t leave the machine shop, though, because at the time, Mark had started his final year at the Rhode Island School of Design, where he earned a Bachelor of Fine Arts in Industrial Design. In 1979, he moved to California’s East Bay area and began working as an automotive machinist in Albany, where he had access to an array of specialized equipment. His father crated the Henderson’s engine and shipped it west to Mark, where, with it fully dismantled, a number of issues were identified. Not the least of the problems was an aluminum lower case half that was pitted, with cracked mounting bosses. Presented with the full scope of the required work, Mark realized this wasn’t going to be a simple proposition and the project was placed on a back burner while he got his life and career underway. Instead of becoming an Industrial Designer, though, as he’d imagined, in 1981 he changed direction and began a seven-year career flying in the Air Force, followed by 29 years as a commercial pilot with American Airlines. All the while, the Henderson remained an abandoned project.

Captain Mark Hunnibell on the vehicle that diverted his attention from a Henderson project for a few years… a stint in the Air Force followed by a career as a commercial pilot. Here he is with a T-38 jet in 1982. [Captain Mark Hunnibell]
Abandoned maybe, but forgotten? Never. After he’d had the Henderson for 22 years, in 2000, he began searching for knowledgeable people, books and other documentation pertaining to the machine to help him proceed with the restoration. In that search, he came across C.K.’s book Across America by Motor-Cycle. “I was looking for Henderson manuals and other information,” Mark explains. “But I was also wondering how people were using these motorcycles when they were new, and here was a book written by a British fellow who rode the same make and model – apart from the electrics – across America. I thought it was an interesting story but didn’t give it too much more thought.” Until, he says, his wife asked what his ultimate goal with the Henderson restoration might be. “What was I going to do with it when it was done, she wondered, and she thought I’d better do something important with it.”

C.K. Shepherd in Kansas City during his 1919 cross-USA journey on his Henderson Four. [C.K. Shepherd]
An idea began percolating. As the centennial of C.K.’s trip was approaching in 2019, Mark set a goal of retracing the intrepid motorcycle adventurer’s journey aboard his own 1919 Henderson Z-2. Designed by brothers William and Tom Henderson of Detroit, their first inline four-cylinder prototype was built in 1911, and production of a 934cc model began in 1912, an example on which traveler Carl Stearns Clancy circumnavigated the globe. While exclusive and distinctive, the Henderson fours proved expensive to produce and the company never really turned a profit. In late 1917, the Henderson brothers sold their company to Excelsior Motor Mfg. & Supply Co. magnate Ignaz Schwinn. All stock, tooling, and production moved to the Excelsior plant in Chicago during 1918. The 1919 Z-models like the ones owned by C.K. and Mark had a 1,147cc four-cylinder powerplant that produced 14.2 horsepower with a three-speed transmission and an added band-style rear brake in addition to the existing rear drum. These were the last of the “Detroit Hendersons,” as in 1920, Schwinn released a new four-cylinder model (the Henderson K) designed by Arthur O. Lemon, a Henderson salesman since 1915 who, after the sale of Henderson, joined the Excelsior Engineering Department.

Captain C.K. Shepherd in his RAF flying gear during WW1. [C.K. Shepherd]
“It became purposeful to give some meaning to my Henderson restoration, and to recognize a pioneer from years gone by,” Mark says of his decision to reverse engineer C.K.’s book and begin planning his own adventure. But first, without the advantages of having a well-equipped machine shop at his disposal, Mark had to have the Henderson restored. After one false start with a Canadian engine rebuilder, Mark located Henderson specialist Mark Hill of 4th Coast Fours in upstate New York. “I took the engine, that had already been worked on, to Mark,” he says. “When Mark realized I wanted to ride the Henderson across the country, he said we’d have to start over with the rebuild – and we did.”

A period advert for a 1919 Henderson Four, as ridden by C.K. Shepherd across the USA. [Popular Science, Dec. 1918]
The frame and other components were restored and painted by John Pierce. According to Mark, most 1918 and 1919 Henderson motorcycle had been finished at the factory in olive green. But after carefully peeling back layers of old paint, John discovered a vivid red color hidden in the nooks and crannies of the frame. While the pre-eminent Henderson expert at the time thought he should just paint the Henderson olive green so he would not have to explain the unusual color, Mark went with the evidence and painted it red. A few changes were made, including new safety rims wrapped in modern beaded tires. Also, the front wheel was laced around a small Honda front hub to provide additional braking – the original Henderson had no front brake. Mark’s Henderson was finished late in 2018.

Mark Hunnibell with his completed 1919 Henderson in what was determined to be the original color. [Mark Hunnibell]
All the while, Mark was researching C.K. Shepherd. C.K. was born 31 May 1895, in Birmingham, England. C.K.’s father, Timothy, was an entrepreneur and inventor who operated XL-ALL, Ltd., a company supplying the pedal and motor two-wheel trade with a range of accessories. C.K.’s older brother, George Frederick Shepherd, was also an inventor and took an interest in early aeronautical adventures. After an incident during testing of a prototype aircraft engine of his own design, however, George remained firmly on the ground. Far removed from the air, George was responsible for inventing and patenting an essential piece of office equipment still known today as the Shepherd Caster. George and C.K. shared their enthusiasm for invention and applying for patents. C.K. was 19 early in 1915 when he enlisted in the Royal Flying Corps and became an Air Mechanic 2nd Class and was soon in France working for the British war effort. Once there, he quickly worked his way up the ranks from private to captain but returned home in mid-1918 to resume work at XL-ALL, where the family company was now helping the war effort by manufacturing some military goods.

C.K. Shepherd with the parents of his friend Steve (Laura and Thomas Stevenson Sr) during his cross-USA journey, at 3450 Clifton Ave in Cincinnati. [Thomas Stevenson Jr]
Shortly after the war ended, C.K. reunited in London with his former comrade-in-arms Captain Thomas Stevenson, Jr., whom he knew as ‘Steve.’ Steve was on his way back to Cincinnati to see his family, and C.K., as he writes in the preface to Across America by Motor-Cycle, “…was wondering what form of dissipation would be best suited to remove that haunting feeling of unrest, which as a result of three or four years of active service was so common amongst the youth of England at that time.” That’s when C.K. decided he’d travel across the Atlantic to visit with Steve, and “have a trot round America.” On 3 June 1919, Shepherd landed in Montreal, Canada. That same day, he crossed into the U.S. and made his way to New York where he bought the 1919 Henderson Z-2-E four-cylinder motorcycle which he nicknamed ‘Lizzie.’ From New York, Shepherd proceeded to ride through New Jersey, Pennsylvania, Maryland, West Virginia, Ohio, Indiana, Missouri, Kansas, Colorado, New Mexico, and Arizona to California, arriving in Los Angeles on August 7 and ending his journey in San Francisco where he sold the Henderson. “Roads? What roads?” C.K. said of the route he took.

‘What roads?’ C.K. Shepherd found no roads or only former cart tracks from the pioneer days on his journey to the West. This is the Arizona border, on a fairly good road. July 25, 1919. [C.K. Shepherd]
Along the way, the four-cylinder engine in his Henderson required plenty of attention and had been rebuilt twice. But after crossing the Mojave Desert, he describes the motorcycle’s overall condition like this, “Externally, she was a mass of string, wire, insulation tape, mud, oil and sand. Internally she was a bundle of rattles and strange noises. Everything was loose and worn; the sand had invaded her at every point and had multiplied wear a thousandfold. Latterly the tappet rods had had to be cleaned and adjusted over a sixteenth of an inch every day until there was no more adjustment possible.” He continues, “The valve rockers were worn half-way through, some more than that. One had worn right through until it had broken in the middle. I began to be afraid that the engine would not hold out even for the 200 odd miles to come.”

A cutaway drawing of the Henderson Four engine from a 1919 Henderson parts list, showing the fairly unsupported crankshaft and crude oiling system – splash cups on the connecting rods dipping into the oil sump. A recipe for trouble, but Hendersons can be amazingly reliable for the period. [Mark Hunnibell]
He managed to nurse the Henderson along, however, to Los Angeles where the machine received considerable work at the Henderson dealer, with a third and final engine rebuild. C.K. notes, “She had had a complete overhaul and several parts of the engine replaced. Numerous telegrams and letters had been flashed across the States to the works at Chicago. They were in vain. Although still under the makers’ guarantee, they would accept no responsibility. I paid the last bill that made Lizzie’s repair account just exceed the amount I originally paid for her [$480 in New York] three months before.”

Mark Hunnibell and C.K. Shepherd’s grandson (Thomas Stevenson III) at 3450 Clifton Ave in Cincinnati in July 1919, the centenary of C.K. Shepherd’s journey. [Dan Wheeler]
Because Across America by Motor-Cycle was not written in a diary format, Mark says it was difficult to determine Shepherd’s exact route. “I spent a couple of years going page by page, line by line, word by word to reverse engineer his book to come up with a close approximation of his route,” he says. During this process, Mark kept meticulous notes, and saw an opportunity to reprint C.K.’s original text along with hundreds of his own details in a ‘Fully Annotated Centennial Edition.’ Mark’s research and extra photographs, newspaper clippings and period advertisements help bring much deeper meaning to C.K.’s story (

After years spent documenting C.K. Shepherd’s journey, Mark Hunnibell published an annotated version of ‘Across America by Motorcycle’, with almost double the page count as it includes many more photos and considerable documentation of the trip. It is available here. [Mark Hunnibell]
Some forty years after being given his Henderson, on 4 July 2019, Mark was in New York City. He was staying a block away from the hotel where C.K. stayed exactly 100 years earlier at the start of his ride. Accompanying Mark was Loring Hill, the son of Henderson engine rebuilder Mark Hill, ostensibly for mechanical support and safety/escort. But it turned out, Loring also needed to be a riding instructor to coach Mark on how to ride this antique motorcycle. “This is the first motorcycle I’ve owned, and I don’t have a lot of time on any motorcycle,” he explains. Was this a rather ambitious undertaking? Yes, indeed. Proper use of the foot clutch and hand shifting the Henderson in traffic was something Mark would get better at, but Loring hopped on and rode the machine from Brooklyn, across the East River, across lower Manhattan, and through the Holland Tunnel to Hoboken, New Jersey. From there, they trailered the motorcycle to Toms River, New Jersey. The next morning, with more open roads ahead, Mark got behind the handlebars and now says, “Every hour, I got better, and at the end of the day, Loring would say, ‘Not so bad as yesterday.’” Willy Fernandez, a friend of Mark’s, had joined as another member of the support team to help maintain the Henderson.

As any Cannonball veteran knows, crossing America by motorcycle on an antique is no easy task! Mark Hunnibell at the Petrified Forest in Arizona. [Willy Fernandez]
For Mark, someone who had easily learned to master military jets and commercial airliners, he didn’t foresee his lack of experience aboard a motorcycle as a liability. But he says his inexperience certainly detracted from his enjoyment. “I couldn’t ride with second nature,” he says, “I wasn’t just riding through space and time, and it was pretty stressful for me. I’d done a tremendous amount of research on C.K. and his book, and maybe I should have spent more time learning to ride my own motorcycle before taking this on.” As comfortable as he might have been getting behind the bars, making stops to visit locations along the route where C.K. made significant observations, things changed in Kansas.

The landscape below the escarpment of La Bajada Hill, south of Santa Fe NM, a nearly-vertical cliff with a precarious trail that Shepherd described descending. [Mark Hunnibell]
Just when things were running smoothly, a mile and a half south of the first refueling stop in Burlingame, Kansas, the Henderson started making a noise like there was gravel in the transmission. Loring deduced the engine was freewheeling, that it had somehow disconnected from the transmission, but he could not diagnose the true nature of the problem at the side of the road. When they managed to open up the engine, it was discovered the flywheel was spinning independently of the crankshaft. Mark likes to joke, and claims he “tried to find a new Henderson crankshaft at auto parts stores, but they were all out of stock, and I never did get through to Henderson in Chicago to see if, after 100 years, my engine was still covered by warranty.” The trip aboard the motorcycle was halted there, but Mark was expected to arrive at the Grand Canyon, where plans had been made to meet C.K.’s son, Charles Drury Shaw. Loring flew home, but Willy and Mark continued “on tour” to the Grand Canyon with the bike in the trailer visiting some of the landmarks C.K. mentioned passing.

Shepherd wrote that 95% of the roads outside of cities were dirt or gravel, like this road, the “highway” to Baltimore. [Mark Hunnibell]
“Willy trailered the bike back home from the Grand Canyon for me, and later I brought the bike back up to Mark Hill to install a new crankshaft,” Mark says. “Our first recovery plan was to occur in 2020. We had planned to trailer it out to Burlingame where it broke, and then ride the bike for some segments of the journey and trailer it for others along the route to San Francisco. But whatever great ideas I had, COVID got in the way of them in 2020 and 2021.” But that break has granted Mark the opportunity to gain more seat time on the Henderson and become even more familiar with its idiosyncrasies. “We got off to a rough start,” Mark says, and concludes, “But I think we would have made it, without that crankshaft failure.” Hopefully, Mark will ultimately complete the ride, and write his own book, one that he’s given the working title Chasing Charles: Across America by Motor-Cycle II.

It all seemed possible, perhaps easy at the start, in Herald Square on July 3 2019, with the former Hotel McAlpin behind him (where Shepherd stayed) and a freshly restored Henderson Four and an optimistic attitude. Stay tuned for further adventures. [Willy Fernandez]


Want more stories of cross-country adventures?  Follow our ADV:Overland thread, and check out our Petersen Museum exhibit!


Greg Williams is a regular Vintagent Contributor, a motorcycle writer and publisher based in Calgary who contributes the Pulp Non-Fiction column to The Antique Motorcycle and regular feature stories to Motorcycle Classics. He is proud to reprint the Second and Seventh Editions of J.B. Nicholson’s Modern Motorcycle Mechanics series. Follow him on IG: @modernmotorcyclemechanics
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