Vintage British Bikes Vintage Motorcycle Parts

23 Apr 2015 | Author: | Comments Off on Vintage British Bikes Vintage Motorcycle Parts
BSA Prototype

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Triumph Trident  was the last major motorcycle developed by Triumph Engineering at Meriden, and was a 750 cc air-cooled unit construction pushrod triple with four gears and conventional chassis and suspension. It was badge-engineered to be sold under both the Triumph and  BSA  marques. The Rocket3 / Trident was part of Triumph’s plan to extend the model range beyond their 650 cc  parallel twins.

Created to meet the demands of the USA market, the smooth 750 cc  three-cylinder engine had less vibration than the existing  360°  twins. BSA fell into serious financial troubles, but during the seven-year production run 27,480 Rocket3 / Trident models were produced.

Although designed in the mid-1960s . the BSA Rocket3 / Triumph Trident engine had its origins in a 1938 parallel twin, the 500 cc   Triumph Speed Twin of 1937 designed by Edward Turner. The 1938 Tiger 100  was a sports version of the Speed Twin, and in essence the Trident three-cylinder engine is a “ Tiger 100 and a half ” (although the triple has a longer stroke than the “ squarer ” Tiger 100 engine). Following Triumph tradition, the  OHV  Trident engine has separate camshafts for inlet and exhaust valves.

The three-cylinder design was started in 1962 by Bert Hopwood and Doug Hele. Meanwhile, test engineers developed the handling of the chassis by affixing lead weights onto a standard 650 Bonneville. The first prototype, P1 . was running by 1965, and it seemed that Triumph might have a machine in production by 1967.

However, the decision to produce a BSA version with sloping cylinders and to employ Ogle Design to give the early Tridents / Rocket 3s their ‘ square tank ‘ look not only robbed the prototype of its lean looks and added 40 lb ( 18 kg ) of weight, but also delayed production by 18 months. During 1966, a P2 prototype was produced with a more production-based Trident engine, with changed bore and stroke dimensions and improved cooling. Ultimately, Hele obtained 90 bhp  ( 67 kW ) from a Trident engine, leading to speculation that if development had sped up in 1964, a 140 mph ( 230 km/h ) British superbike could have been a reality in 1972.

Although most British motorcycles used a wet multiplate clutch, this triple had a dry single-plate clutch sited in a housing between the primary chaincase and the gearbox. Mounted on the end of the gearbox mainshaft where one might expect to find the clutch there was instead a large transmission shock-absorber.

All the three-cylinder engines, and the Rocket 3 motorcycles, were produced at BSA’s  Small Heath site, but final assembly of the Triumph Trident model was carried out at Meriden in Coventry. The major differences were the engine and frame: The BSA had an  A65-style double-loop cradle frame (with engine mounted at a slant), while the Triumph had a Bonneville-style single down tube frame with vertical cylinders. Other differences were cosmetic.

Triumphs sold better in the US despite BSA’s  Daytona racing successes of the early 70s . However sales did not meet expectations, and for the 1971 model year a fifth gear was added, creating the models  BSA A75RV  and  Triumph T150V . BSA were having financial difficulties, and only some 205 five-speed Rocket 3s were built before production of the BSA variant ceased. Production of the five-speed Triumph T150V (with a front disc brake replacing the original drum) continued until 1974. For the 1975 model year the Trident was updated to the  T160 .

The prototype triples had a classic “ Triumph look ” with a rounded tear-drop tank. However, BSA/Triumph commissioned OGLE design company to create a “ modern new look ,” this redesign leading to an 18 month delay. The result was a squarer fuel-tank and a less traditional BSA/Triumph look, and the BSA was given sloped cylinders and ‘ RayGun ‘ silencers.

The Rocket 3 / Trident was introduced in the summer of 1968 to critical acclaim, but only four weeks later it was upstaged by the introduction of the Honda CB750 . Compared to the British triple, the more sophisticated CB750 had a five-speed gearbox, overhead camshaft, oil-tight engine, electric start and disc brake. The Honda outsold the Triumph in the target USA market, and in 1970, in a bid to revive sagging sales, Triumph restyled export versions with the original ‘classic’ look.

When, in 1968, the new triples were shown to the American BSA-Triumph management, they were disappointed. They knew Honda had a bike coming along, and felt the price of $1,800 ( £895 ) was too high and technical details (like vertically-split crankcases and pushrod OHV  valve train were far from “ cutting edge .” However, they acknowledged that the bike was fast, and the USA sales team decided to launch of the bike by using a Rocket-3 to set some records at Daytona, (records which were only broken in 1971 by the Kawasaki Z1 ).

Vincent Comet Series A (1937)

Series A Vincent-HRD singles were the model which set the Stevenage maker on the road to immortality. The story goes that the engine was designed in under four months, as Vincent was disillusioned by the performance of ‘bought in’ engines.

Well-known on the classic scene, genial Cumbrian Bill Bewley restored this fabulous Series A Comet just in time for the 2009 Stafford April show, where it was among the prizes, picking up the award for Best Pre-WWII . Since then, it’s graced the Carole Nash stand at the 2009 International Motorcycle show, while it was on the main Mortons stand at Stafford April 2010. However, it was a bit over ( Black ) shadowed at Stafford 2010 – Bill’s equally well restored version of Vincent’s 125mph roadster won top prize there, chosen as best in show.

BSA Prototype

The Series A Comet shouldn’t be overlooked though. Arguably the ‘ A ’ single was the most important motorcycle in Vincent history, and tales of its conception are legendary. So the story goes, disgusted by the performance of ‘ special ’ proprietary  JAP  engines fitted in his Isle of Man TT racers during the 1934 event, Phil Vincent vowed to no longer depend on bought-in engines.

In just four months, the in-house designed prototype single cylinder engine was ready for display at the Olympia motorcycle show, whereupon Phil Vincent ( PCV ) confidently predicted a top speed of 80mph for the cooking Meteor, 90mph for the sportier Comet and a ton for the racing TT Rep… despite the fact no engine had yet been run.

However, PCV’s confidence was proved well-placed – and there was no real surprise, as the engine was the work of well-respected Australian Phil Irving. The ‘ high cam ’ engine – the camshaft is set as high as possible in the timing chest, allowing short pushrods to be used; a similar set-up to Velocette’s M series – proved itself a fast and reliable unit.

The Series A single of course was doubled up to create the first Vincent ( HRD ) V-twin . while the Post-WWII singles (and twins) were extensively redesigned. However, without the Series A singles, then there would surely have been no Rapides, no Black Shadows, no Black Lightnings, no Gunga Din, no Rollie Free record attempt, no Nero… The importance of the Series A single in the Vincent pantheon should not be underestimated; now, the model has become desirable and with its historical significance and 1930s good looks, it’s hardly surprising.

Specification: HRD Comet

Year of manufacture:  1937

Engine type:  Ohv single

Bore x stroke:  84x90mm

Capacity:  499cc

Carburettor:  single Amal

BSA Prototype

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