Boardwalk racing motorcycle
CHRIS GORDON USES SKILL AND ARTISTRY TO MAKE RACING MOTORCYCLES IN HIS SHED
A sheddie recreates a 1920 American racing bike in his Christchurch shed
Chris Gordon has been devoted to the internal combustion engine since his earliest days when his next- door neighbour was a motor mechanic.
At 14 he was a crew member for Ron Collett, who successfully ran a Top Eliminator class dragster at strips throughout New Zealand. His Chris Gordon Racing Team won the 1998/’99 125cc New Zealand Road Racing Championship, with well-known rider Dennis Charlett riding a Honda RS125 that Chris owned and prepared. Chris and his team ran the bike in the 125cc class at the Australian MotoGP at Phillip Island in 1999.
Chris has also from a very early age made things: models, an electric bicycle, an electric go-kart, a fibreglass road-registered scratch-built car, and a 500cc V8-powered Grand Prix racing bike. He has a minimalist approach to tools and equipment, but to make the racer’s V8 engine he had to buy and master a small lathe and a serious large and highly capable milling machine. The alternative would have been to get the machining and development done professionally. Chris calculates that this would have involved thousands of hours of very expensive machine time — say, 3000-plus hours at $100 per hour. That’s a lot of money.
Chris is outstandingly well organized and his workshop is a model of thoughtful planning. Partially this is a result of his racing background — you need to be able to access the necessary gear immediately at the track and there is no place for notneeded stuff. It is also a reflection of his practical approach: “I can make a mess, but I can’t work in a mess.”
Development of the V8 racer
Chris has an ongoing interest in the use of multiple engines in a bike and came up with the idea of making a 500cc V8 engine by mating two 250cc four- cylinder engines. The donor in-line-four motors chosen were Kawasaki ZXR250s, which can rev to 20,000 rpm, complete to their crankshafts. These were bolted to castings, which Chris made the patterns and moulds for and which he machined. The original sump is retained at the bottom of the engine. Gears at the end of each crankshaft drive the common clutch. The meshing of these gears is arranged so that the combustion impulses don’t coincide, making the engine run smoother.
Having made an engine, the next step was to make a bike for it to power. This required more work than Chris is happy to recall, but the immaculate fibreglass petrol tank and fairings reflect his skill and painstaking approach.
Chris doesn’t race motorcycles himself and so would have had to let someone else compete on the bike. This brought the issue of his personal liability should an accident occur. The inevitable blowback from an accident involving a machine that he made the vast majority
“I can make a mess, but I can’t work in a mess”
of was not something he was prepared to contemplate. So the racer has never raced.
For his next project Chris decided that something much slower would have fewer legal risks. A friend was building a replica of a 1920s board-track racer and this appealed as something that could be built from readily available materials but would be a significant technical challenge.
Chris would like to have been born in 1880 so that he would have been able to produce bikes at the dawn of motorcycle racing, before World War I, when the fastest form of racing was on the board-track racers that competed on banked, oval, wooden motordromes.
The only part of Chris’ board-track racer that dates from the early part of last century, is the JAP crankcase and crankshaft. JAP engines were made by JA Prestwich Ltd in England from 1895 to 1963. The rest is new, purchased locally and online.
The wheels and tyres are new and are the most expensive parts of the racer. They were imported from America,
Chris would like to have been born in 1880 so that he would have been able to produce bikes at the dawn of motorcycle racing
where a genuine Harley-Davidson Board Track Racer can fetch more than $200K. Professionally made replicas are available in the US from $27K.
Chris started with old photographs of racers and, taking the wheels as a guide, scaled the images up to arrive at the dimensions of his machine.
The frame is constructed of seamless mild-steel tubing brazed into bracketry made by Chris from solid steel. First, the pieces were turned to size on the lathe, then notched on the mill, then temporarily bolted together, and finally TIG welded together.
The eye-catching handlebars were
bent on the tube bender that Chris constructed when making the V8 bike and incorporate an ingenious throttle mechanism using rods. As the handlebars are turned, a sliding section stops the throttle setting from changing.
The engine is based on a 1908 250cc JAP crankcase and crankshaft; a VW Beetle cylinder and piston; and a Chinese-made connecting rod, which is a copy of a very early Harley-Davidson one. Chris designed the head, with its exposed valve gear and four valves. It was cast by CanCast in Timaru, and machined by Chris. The valves and springs are Honda copies, the rockers are modified Lifan, and the pushrods have been fabricated from silver-steel shafting. He is at a loss to understand why the valve gear was exposed on the original racers, as the weight of an effective, oil-tight cover would be minimal. The dusty environment of the board tracks would have promoted rapid wear. His best guess is that it was fashionable.
Is it real or is it a copy?
I first saw Chris’ replica board-track racer at this year’s New Brighton beach race, where it was surrounded by an admiring crowd, despite the presence of literally hundreds of fascinating two-wheelers, and a smattering of very desirable fourwheeled devices.
Even very knowledgeable observers were unsure if the bike was the real thing or a copy. The most discussed aspect of the replica was the flawlessly aged patina of the steel frame, which was gratifying to Chris because he had gone to extraordinary lengths to achieve the correct look to the bike’s finish.
The frame tubes were sanded, painted, assembled, then the visible paint was sanded off, a chlorine solution lightly sprayed on and left to oxidize the surface of the steel. When dry, the tubes were wiped with an oil-soaked rag. The resulting finish is exactly what you would expect to see on a hard-used racing machine after more than a century had passed. Anyone working on it would see the original paint finish when the frame was disassembled.
The mock tool-roll attached to the vintage leather saddle is turned from wood recycled from a hardwood pallet. It contains the battery and the electronics of the ignition system, which were purchased online.
The drive from engine to rear wheel is by belt. The belt, manufactured for the emergency repair of industrial drive belts, is made from rectangles of polyurethane riveted together, originally bright orange coloured. It drives a period-correct large pulley, also made from recycled pallet wood, which is attached to the rear wheel by brass plates. The large diameter of the driven pulley gives a high gearing, which means the slow-revving engines of the 1910s could power the racers around the banked wooden tracks at lethal speeds.
The bike has no brakes; only one gear; but, unlike an original example, does have a clutch. This is a copy of the clutch from the celebrated Honda GY6 scooter, which is now produced in China in vast numbers, so parts are remarkably cheap.
The dangers of racing these machines at the motordromes were numerous. The speeds were high (well over 100mph [161kph]), tyres were outstandingly unreliable, safety equipment consisted of goggles and a thick jumper, brakes were non-existent, and the surface could be slippery with oil from the total-loss oiling systems or break up into holes and nightmarish splinters. If you went too fast you could slide off the upper edge of the banking to your doom — hence the expression ‘over the top’. There was probably also an expression for being impaled by long splinters of wood from the track, but it hasn’t survived.
Some motordromes used 100x50mm boards on the edge, and others were 300x25mm. The amount of banking on the turns varied from 30° to more than 60°. The spectators sat at the top of the track, looking down on the racing, and were in great danger — competitors losing control and sliding over the top would land in the crowd. Deaths were a regular occurrence. At one race, four young boys were killed when a riderless bike struck their heads as they leaned out over the edge of the track.
The popular name for the tracks was ‘murder-dromes’. In America from the end of the 1920s, motorcycle racing increasingly took place on dirt tracks which were not only safer but also didn’t need to be extensively rebuilt every few years. The Indianapolis banked oval, dating from 1909, has survived because it was made of brick. Brooklands in England, opening in 1907, was concrete and it only closed when World War II broke out in 1939.
The dangers of racing these machines were numerous
Chris doesn’t race bikes himself, he enjoys building them
The crankcase patterns for the V8 engine
One of the many jigs Chris made. In this case, for the machining of the V8 racer’s crankcase
Chris assembling the mould for the V8 racer’s glass-reinforced-plastic (GRP) (fibreglass) petrol tank
The GRP body of the V8 racer
The 11 component pieces of the petrol tank mould
The V8 racer’s fabricated GRP airbox
TheThe artistartist andand hishis workwork
Frame brackets machined from the solid and the several pieces TIG welded together
The reproduction racing number was made from an old biscuit tin. The rods controlling the throttle can also be seen
The wooden pattern for the head of the board-track racer’s engine (left) and an unfinished cast iron head (right)
The finished head and the exposed valve gear and pushrods
Right: The board-track racer on a section of reproduction board track. Note the post- earthquake vertical support