Cycle News - Archive Issues - 1980's

. 00 ~ From any way you look at It. the 1933 Rudge &OOcc TT Replica belonging to Briton Howard Place is beautifully finished and a winner In it81ime. Racer Test 1933500cc Rudge TT Replica By Alen Cathcart The late 1920s were a time of great technical advance in the development o~ the British racing motorcycle. Norton and Velocette introduced overhead camshaft models; the positive stop gearchange was pioneered by Veloce's Harold Willis; and Rudge achieved success both on the track and in the showrooms 22 with two features which find continued expression today: coupled brakes and the four-valve head. Paired valves were nothing new even then, but a combination of sweeping success in competition and astute marketing thereafter have made the name of Rudge synonymous with four valves per cylinder. Indian pioneered the concept before the Great War - to be copied by Harley and other American manufacturers on their racing machines - while in Europe, Guzzi took the idea a stage further by winning the inaugural European Championship in 1924 with an overhead camshaft-driven four-valver. But the idea took a while to catch on in Britain, though it was always on the cards that it would be Rudge who exploited it. Born out of a merger between two well·respected Coventry bicycle manufacturers, Rudge-Whitworth - to give the company its proper name - was consistently top of the expon league in the British motorcycle industry, and one of its key markets was Italy. Many hundreds of Rudges were sold there in the first !l0 years of this centry - indeed it was a contract from the Italian army that kept the company afloat to the end of the Great War - and Rudges are a common sight even today at Italian vintage meetings, Rudge's designer, John Pugh, would, therefore, have been more than usually alive to developments in 'that country, and when the time for a long-overdue redesign of the venerable F·head engine arrived, he went the whole hog and introduced paired valves. The design became a feature of Rudge machines until the company's demise with the arrival of WW2. Interestingly enough, the machine on which the Rudge name reappeared earlier this year is faithful to the theme, with its four-valve Weslake engine. In determiriing his four-valve design, though, Pugh leaned heavily on the British pioneer in the field, Sir Henry Ricardo's Triumph, introduced one year before in 1922: Like the "Riccy," the new Rudge had pushrod· operated parallel valves with a pent roof combustion chamber and splayed exhausts. This was to be the Rudge formula for the next few years, but Rudge publicity of the time shows that their reasons for introducing the design were as much to counter the po«?r valve material of the time as anything. While the !l50 and 500cc models were four-valvers, the catalog claimed that "the need for this design becomes less acute as the cylinder size decreases, so that for the new 250 we feel justified in adopting the simplification of two valves per cylinder. " Honda engineers of the early '60s probably couldn't have, disagreed morel The. blurb continued: "The advan· tage of having four valves is that a very large port area can be obtained with valves which are both lighter and vastly stronger than those of an equivalent two-valve design. Valve breakage under normal conditions is therefore unknown." Modern wisdom teaches that fourvalve heads have other advantages, chiefly less risk of valve float due to the lighter reciprocating weight and shoner flame path due to the central plug. But at a maximum 6,000 safe rpm from the bottom end technology of the time and without the lower reciprocating weight and more accurate timing of an overhead camshaft design, Rudge were not able to make the spectacular leap forward in four-stroke technology that came from the Orient after WW2. Instead, their four-valves brought simply better breathing and greater reliability, which nevenheless in the long and arduous races of the day were more than enough to ensure dramatic success. This did not come immediately. Indeed, it was only after a couple of y~ars' largely unrewarded e£fon by development engineer George Hack and the arrival of the .legendary Graham Walker from Sunbeam that the team began to come good. It was Walker (an amazing all-rounder who actually raced while receiving a disability pension in respect of serious· injuries suffered during the Great War) who put the marque on the racing map with a stirring victory in the 500cc Ulster GP in 1928. Not slow to capitalize on this success, Graham who was also Sales Manager for the company - soon had a replica on the market, the famous Rudge Ulster, thus offering the private owner a design and performance not far removed from the works racers. Indeed, it became established Rudge practice to catalog this year's works racer as next year's production model, and since the changeover against the normal trend - usually occurred Just after the IT in order to capitalize on what were regularly highly satisfactory results, this caused no little problem for Rudge privateers in the September Manx GP races. Works bikes were banned from these, so when Rudge runners staned showing up with all sorts of mods not shown on that year's catalog Ulster model, it be· came necessary to relabel the production racer, which hencefonh was known as the IT Replica. One such machine is the subject of this test. The Ulster became the more "cooking" model thereafter. 19!10 was the year of Rudge's greatest triumphs (no pun intended), when they scooped the first two places in the Senior IT and the first three in the Junior. as well as numerous other. Classic wins on the Continent. The Junior result was a tremendous display of superiority, made all the more remarkable by the fact that the 'machines used were totally untried and boasted a radical new form of head design: radial valves. Though relatively common practice in the airplane engine field, this was the first time that this design had been used on a motorcycle; George Hack's layout called for a complicated system of six rockers, sitting in roller bearings, to operate the four radially-disposed valves, but the result was a more desirable hemispherical combustion chamber and more meat between the exhaust valves, thus reducing the risk of the head cracking. The radial design brought great success to Rudge over the next couple of years, but Hack wasn't satisfied, for the six rockers increased reciprocating weight and were complicated to maintain. After abortive experiments with a three·valve head (thus again pre· dating Honda)', a compromise was arrived at, and from 19!11 on, the works 500cc machines wore semiradial heads, with parallel inlet and radial exhaust valves, thus achieving the best of both worlds. Incorporation of this design into the customer version was delayed until the 19!12 November show. Bearing engine number 99, our test machine, which is so fitted, must have been one of the first such models to be delivered. The IT Replica was a genuine customer racing machine that could also be supplied with a lighting set for use on the road. most likely for getting to and from meetings (those were the days!). But in fact, our bike did not receive its EXO 840 registration number until April U. 19!18, indicating Specifications Engine. , , . . . . . . .. Pushrod alngle-c:ylincler four-valve four-stroke with perallellnlet and rotary exhaust valvas 8& x 88rnm Bore x stroke Capacity 499cc Carburatlon Single 1\" Amel with dual float bowls Compression ratio 7.25:1 Output 30 bhp @ 5.800 rpm Gearbox. . . . . . . . .. Four-speed Rudg.Whltworth conatant-mesh with chain primary Ignition. . . . . . . . . . . . .. . .. . . . . . . . . . . . . . . . . . . . .. BTH racing magneto Weight 296lba. Brakes S" Rudg.Whltworth Proportional Coupl!td front and rear lbothSLSI Frame... Single downtuba aeml-cradle with drop-forged steering head Suspension Front D-seetlon girder forks with encloaed centrel spring; rigid rear Front 3.00 x 21 on WM2 Wheelaltlres Reer: 3.50 x 19 on WM2 95 mph Top speed Year of manufacture 1933

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