Founder’s Day at Stan­ford Hall pro­duced over­head camshaft ma­chin­ery from around the world, but also pro­vided a re­minder that the Bri­tish con­tri­bu­tion was not just re­stricted to the Nor­ton, AJS, and Ve­lo­cette rac­ing mod­els

Real Classic - - What Lies Within -

The theme for the VMCC Tav­ern­ers’ Stan­ford Hall meet­ing this year was ‘over­head camshafts’. The venue is close to home for PUB, but she has missed re­cent years due to clashes with other events. It clashed again, but for un­con­nected rea­sons it was the other event that lost out this year, so she went along. She took (trail­ered of ne­ces­sity) a suit­ably themed race­bike, ob­vi­ously not from the House of Vin­cent – although it may sur­prise read­ers to know that they did make one. Just one. It was an Earl’s Court show model NSU-Vin­cent Max, but cost­ings showed that this An­gli­cised model – to re­duce im­port du­ties – would not be prof­itable although the 98cc ohv and 123cc 2-stroke Foxes were mar­keted.

It is pop­u­larly sup­posed that the Bri­tish in­dus­try was al­ways con­ser­va­tive, and made wor­thy plod­ding go-to-work bikes at best, un­like the Ja­panese with their ex­otic and well equipped bikes that brought elec­tric starters, in­di­ca­tors, etc to our mar­ket. But it ain’t nec­es­sar­ily so. Over­head camshafts are a case in point, and over­head camshafts were the theme at Stan­ford Hall. For that rea­son PUB took along her Grand Prix dohc Mon­dial, ac­com­pa­nied by B44 Clive’s just­be­ing-com­pleted Par­illa restora­tion. Ac­tu­ally, the Par­illa is not tech­ni­cally over­head cam, as its camshaft is sit­u­ated at the top of its camshaft tun­nel just along­side the head, in­stead of over it. This ne­ces­si­tates tiny lit­tle pushrods, inside inch long rub­ber bel­lows, the ar­range­ment giv­ing most of the ohc ad­van­tages of re­duced valveg­ear re­cip­ro­cat­ing weight, but still per­mit­ting the head to be re­moved with­out dis­turb­ing the camshaft drive or tim­ing. Ve­lo­cette and Vin­cent used ‘high camshafts’ as high inside their tim­ing cases as they could eas­ily

Founder’s Day at Stan­ford Hall pro­duced over­head camshaft ma­chin­ery from around the world, but also pro­vided a re­minder that the Bri­tish con­tri­bu­tion was not just re­stricted to the Nor­ton, AJS, and Ve­lo­cette rac­ing mod­els

ac­com­mo­date, but nowhere near as ‘high’ as the beau­ti­ful Ital­ian Par­illa.

The 1920s was the era when Bri­tish fac­to­ries were hot with ohc de­vel­op­ments. Ev­ery­one knows about Manx Nor­tons (de­rived from the Arthur Car­roll re­place­ment for Wal­ter Moore’s orig­i­nal CS1 of 1927), and the cammy Velo which ac­tu­ally pre­ceded it, orig­i­nat­ing in 1925, but they were not by any means the only ex­am­ples, nor even the first. Le Vack had al­ready gone record break­ing in France in 1923 with one of Val Page’s JAP dohc race en­gines with the slightly un­usual lay­out of cams and fol­low­ers/ rock­ers. Rolls Royce are cred­ited in some cir­cles for spark­ing off UK ideas, since their Ea­gle aero en­gines had been very suc­cess­ful in WW1 (but they had only adopted the idea from else­where). How­ever, the mo­tor­cy­cle world had plenty of prece­dents of its own, es­pe­cially the rac­ing dohc Peu­geot of 1913.

At Stan­ford Hall the area marked out for ‘theme ma­chines’ was very lim­ited, and cer­tainly in­ad­e­quate for such a wide rang­ing theme. Even al­low­ing for it be­ing a VMCC event, and thus only for over 25 year-old ma­chin­ery, that in­cluded most of the Ja­panese bri­gade (Honda ar­riv­ing with theirs over 50 years ago, and the other Ja­panese fac­to­ries go­ing 4-stroke around ten years later). A few in­ter­est­ing ma­chines did as­sem­ble, in ad­di­tion to the Mon­dial and Par­illa. These in­cluded the ex­pected Nor­tons, Ve­lo­cettes, AJS ‘boy racer’, but also Arthur Far­row’s MV 600cc four – an ex­am­ple of the first model that MV re­leased to the mar­ket, and pur­posely with shaft drive and only 600cc to dis­cour­age cus­tomers from try­ing to race it. But for a re­minder that ohc was once es­poused even by the Bri­tish in­dus­try it was nec­es­sary to keep the eyes open when look­ing around.

Cammy Ve­los, of course, abound, not least be­cause for some years they were the main­stay of the Ve­lo­cette range, and not just the rac­ing mod­els in the cat­a­logue. But the ir­re­press­ible Rhodes team (Ivan and Gra­ham) also had the 1939 su­per­charged con­traro­tat­ing twin Roarer not only on show, but started up for the crowd. In 1930 the idea of ohc for the road­go­ing mod­els was not con­fined to Ve­lo­cette, and both Match­less and Ariel showed ohc fours at Olympia – the 600cc V4 Sil­ver Hawk from Match­less and the 500cc Square Four from Ariel. The lat­ter lived on a lit­tle longer of the two in ohc form, but re­gressed to pushrods by the later Thir­ties. It is doubt­ful whether ei­ther of those fours could use­fully ben­e­fit from their over­head cams given their tor­tu­ous in­take plumb­ing, and pushrods made less de­mands on the lu­bri­ca­tion and cool­ing sys­tems of the time, as well as eas­ing head re­moval for de­cok­ing (no dis­tur­bance of the valve tim­ing). Nev­er­the­less a num­ber of the ohc Ariels were to be found at Stan­ford Hall.

From the smaller fac­to­ries, the Excelsior Manx­man is prob­a­bly the best re­mem­bered ohc (and with most sur­vivors), but oth­ers were also giv­ing it a try. The old firm of Chater Lea (like BSA a maker of lugs and fit­tings to the in­dus­try be­fore be­ing man­u­fac­tur­ers them­selves) pro­duced a face-cam en­gine that had some suc­cess break­ing records, be­fore they faded from the mar­ket in the re­ces­sion­ary 1930s. OK Supreme also tried a novel ap­proach, launch­ing their new 250cc ma­chine with the cams fit­ted to the ver­ti­cal tower (with an in­spec­tion win­dow to see if oil was reach­ing the cams – hence the name ‘Light­house’). This made its first ap­pear­ance at the 1930 TT where it broke the lap record from a stand­ing start, nev­er­the­less it also faded quickly away in the De­pres­sion. How­ever, the fac­tory still of­fered a more con­ven­tional shaft-and-bevel ohc from the mid-Thir­ties, of which one was on show at Stan­ford Hall.

An­other rare ex­am­ple of the ohc breed, which also ap­peared on Founder’s Day, was the Hum­ber ver­sion. A tale, quite pos­si­bly apoc­ryphal, told that Hum­ber in 1930 were on the skids, soon to be part of the Rootes Group, which had no in­ter­est in mo­tor­cy­cles. The Hum­ber de­signer had his new ohc de­sign burn­ing a hole in his pocket, and knew that un­der the new regime it would not see the light of day – so he got it into pro­duc­tion as quickly as pos­si­ble just to see it in the metal. A pe­cu­liar­ity of their ad­ver­tis­ing was that they re­ferred to it is a 3.49 h.p. OHV (camshaft type).

The post-war UK years were ded­i­cated to wor­thy transport and cur­rency earn­ing ex­ports, so real glam­our dis­ap­peared from the UK mo­tor­cy­cle scene (save for the Vin­cent, PUB must add), with only the ohc race-bred Nor­ton, AJS, and Ve­lo­cette (soon to dis­ap­pear it­self ) con­tin­u­ing. But it was so nearly not so. Val Page’s par­al­lel twin de­signs of 1939 had planned for both pushrod and ohc ver­sions, no doubt the lat­ter as a sport­ing com­peti­tor to Turner’s Tri­umph, but the war in­ter­vened. An ohc BSA twin is il­lus­trated in Hop­wood’s ‘What­ever Hap­pened To The Bri­tish Mo­tor­cy­cle In­dus­try?’, which may be such a pro­to­type, but as Page, Turner, and Craig all served spells at BSA in those tur­bu­lent times ex­actly whose hand was in which pro­to­types may now be dif­fi­cult to un­ravel.

So, in the post-war era, it was Italy, and for a while Ger­many, who led the way with new ohc de­signs. In the small classes FB Mon­dial, in rather an­ti­quated cy­cleparts (with girder forks) took the 125cc world cham­pi­onships in 1949/50/51 with dohc works mod­els, and af­ter a less suc­cess­ful pe­riod re­turned with a re­vised de­sign housed in more upto-date cy­cleparts to blitz both the 125cc and 250cc cham­pi­onships in 1957. In the

large ca­pac­i­ties it had been Gil­era dohc fours (by Re­mor, who had de­signed the pre-war Ron­dine four) that had de­posed Nor­ton even with their Feath­erbed frame de­vel­op­ment, such that even Duke had to de­fect in or­der to win. Only af­ter the Gil­eras pulled out in 1957, to­gether with Moto Guzzi and Mon­dial, did the MV fours be­come un­beat­able. Du­cati ob­tained the ser­vices of one-time Mon­dial em­ployee Fabio Taglioni, who promptly set them onto a win­ning trail in the light­weight classes with the ohc Du­catis that sired a long line of sohc, dohc, and desmod­romic sin­gles, be­fore com­menc­ing the L-twins that are still the main­stay of Du­cati to­day.

For a time, Ger­many also pro­vided some lead­ing de­signs, although with few ohc mod­els. BMW con­tin­ued their ohc box­ers, just for rac­ing as they had pre-war, but NSU pro­vided nov­elty with their 250cc Max de­sign, in which the camshaft is driven by a pair of con­nect­ing rods (rather like the wheels of a steam rail­way en­gine). This was de­vel­oped into a po­tent rac­ing iron (which Hail­wood rode in his early years), of which one was dis­played at Stan­ford Hall. The Grand Prix win­ning NSUs were much more com­plex and so­phis­ti­cated twin cylin­der de­signs, now of ex­cep­tional rar­ity.

The Ger­man in­dus­try col­lapsed rather ear­lier and more dra­mat­i­cally than that of Bri­tain, in spite of its en­gi­neer­ing rep­u­ta­tion – but not with­out a legacy. Not only the Ariel Ar­row, but also Yamaha’s two-stroke twins were in­flu­enced by Adler, and dur­ing their ‘copy’ phase the Ja­panese made mod­els clearly pat­terned on Ger­man and Bri­tish ma­chines. How­ever, when Honda went rac­ing, they ob­tained a rac­ing dohc Mon­dial (which is re­put­edly still in their mu­seum) for ex­am­i­na­tion, but their first TT ma­chines were twin cylin­der shaft and bevel dohc ma­chines with some­thing of the look of the GP NSUs about them.

There was one more ohc ma­chine at Founder’s Day, to re­mind us that even in the post-war era at least some de­sign­ers re­mained for­ward think­ing; the 4-valve MC1 racer. Tech­ni­cally, this might be re­ferred to as

‘dou­ble over­head cam’ be­cause it does have two camshafts, but prac­ti­cally they op­er­ate more like a sin­gle camshaft but ‘bent’ (us­ing a pair of shal­low bevels) so as to en­gage with rock­ers aligned with the ra­dial four valves. Nev­er­the­less its per­for­mance im­pressed Ge­off Duke suf­fi­ciently that he planned to race it, spook­ing the con­ser­va­tive BSA board, who had not ap­proved his ven­ture, so much that they canned the project when the tech­ni­cal team could not guar­an­tee it would win. This was a throw­back to BSA’s 1921 hu­mil­i­a­tion when all six of its spe­cially de­signed and pre­pared TT ma­chines failed even to fin­ish.

Re­put­edly six sets of parts were again made, of which Hop­wood’s book says that three were as­sem­bled, and now it ap­pears that there are three again. One com­plete ma­chine is on show at the Na­tional Mo­tor­cy­cle Mu­seum, and an­other at Sammy Miller’s mu­seum, but it was nei­ther of these on the Rudge stand at Stan­ford – badged both as BSA and Rudge. The why of that may be con­nected with that board’s fear of hu­mil­i­a­tion, as ap­par­ently they con­sid­ered rac­ing un­der the Rudge name, said the owner. Sadly none of that was to hap­pen, de­vel­op­ment stopped, and the ma­chine that Hop­wood says was de­signed for ex­ploita­tion as a cat­a­logue model dis­ap­peared.

Nor was that the only ohc that got canned, although it was perhaps the most ad­ven­tur­ous and in­ter­est­ing. But Royal En­field pro­to­typed a 175cc job, which has sur­vived and crops up from time to time hav­ing just fea­tured in ‘ The Clas­sic Mo­tor­Cy­cle’. Ve­lo­cette, so of­ten thought of as liv­ing in the past in spite of their many at­tempts to break the mould, also de­signed a 250cc ohc en­gine around 1960. Un­for­tu­nately it fell into abeyance due to pres­sures of work else­where (Ber­tie Good­man did not re­mem­ber ex­actly why). A 5-speed gear­box was pro­posed, us­ing the then new Royal En­field clus­ter, but RE would not play ball, so the unit was de­signed and ma­chined to ac­cept an Ariel/Bur­man clus­ter from the Leader/Ar­row – but never com­pleted. Then, in his fi­nal years the great de­signer Val Page (whose JAP dohc of 1923 was men­tioned ear­lier) planned a 50cc unit for the Pixie, us­ing a then fairly novel belt drive ohc. That was over-ruled by Edward Turner.

Then there was the Tri­umph ‘Ban­dit’ and BSA ‘Fury’ – but the less said about them the bet­ter…

Above: The Founder’s Day ‘theme bikes’ area, with Par­illa and Mon­dial in front of the 1960s MV 600cc shaft­drive fourBe­low: In the Ban­bury re­port PUB de­scribed a Match­less gun plat­form, ac­com­pa­nied by a rub­bishy pho­to­graph. At Founder’s Day the owner had it up and run­ning, and is here en­ter­ing the dis­play ring

Above: An odd­ity of the first MV four model was its use of ca­ble op­er­ated disc brakes, from Cam­pag­nolo (also used on some early EgliVin­cents)Right: B44 Clive’s lat­est restora­tion is this lovely Par­illa, pho­tographed with the stately home of Stan­ford Hall pro­vid­ing an im­pres­sive back­ground Most Ariel Square Fours are the later 1000cc pushrod mod­els, but this one is the ear­lier and orig­i­nal over­head camshaft de­sign and prob­a­bly 500cc Bronze head ohc en­gine of the OK Supreme. Ivan and Gra­ham Rhodes brought the one-off 1939 Ve­lo­cette ‘Roarer’ su­per­charged twin to Stan­ford Hall, and even ran it up for the crowd. They kindly al­lowed Jac­que­line to sit on it, af­ter promis­ing not to ride it away. Had there been a kick­start she would have proven a liar One of the smaller man­u­fac­tur­ers to try their hand at an ohc rac­ing model was OK Supreme. This is not the fa­mous ‘Light­house’ model, but their more con­ven­tional of­fer­ing from 1937

Hum­ber, bet­ter known for their cars, also had a crack at the ohc sin­gle, just be­fore they were taken over by Rootes Group and ceased mak­ing mo­tor­cy­cles Hum­ber ohc en­gine, surely in­flu­enced by the con­tem­po­rary Ve­lo­cette K series?

Above: The Max in­cor­po­rates a very un­usual form of cam drive, us­ing a pair of con­nect­ing rods (phased at 90 de­grees) which can just be seen in this cut­away en­gineRight: In the 1950s NSU made var­i­ous ver­sions of their ‘Max’ 250cc sin­gle, in­clud­ing the Sport­Max. Here is a replica ex­am­ple now An MV four 750S on the Ital­ian Own­ers Club stand. MV con­tin­ued to fit shaft drive to their road­sters, pos­si­bly to ab­solve the rid­ers from chain ad­just­ing chores, but also to dis­cour­age them from rac­ing (but that did not al­ways work) The BSA MC1 ohc racer of 1952 was a prod­uct of the long run­ning Hop­wood and Hele part­ner­ship, and was only ever made in pro­to­type form. This one was shown on the Rudge stand, due to a loose his­tor­i­cal Rudge con­nec­tion

No, not ohc, but a rare ma­chine ob­vi­ously be­ing used is al­ways a joy to see. The stuff sack of camp­ing gear shows that this big En­field V-twin is no trailer queen Left: In 1961 Ve­lo­cette con­sid­ered de­vel­op­ing a new and up-to-date model – get­ting as far as this 250cc ohc pro­to­type en­gine, a con­cept aimed at the younger mar­ketBe­low: The BSA MC1 racer fea­tured a fully ra­dial 4-valve head op­er­ated by over­head cams. Tech­ni­cally there are two such camshafts, but it does not re­ally war­rant a dohc de­scrip­tion as they are ef­fec­tively just a ‘bent’ sin­gle over­head cam con­fig­u­ra­tion

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