Board­walk rac­ing mo­tor­cy­cle


The Shed - - Contents - By Ritchie Wil­son Photograph­s: Juliet Ni­cholls

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.

Board-track racer

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

Cap­tion here...

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

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