It was perhaps inevitable that Triumph would produce a true retro-bike; which manufacturer, after all, has a more fitting heritage on which to draw? The company first sounded out the market with the Thunderbird, which was really just the standard steel-frame modular triple in a zoot suit, but strong sales showed the potential.
Now along comes the Bonneville twin, bearing an illustrious name and simply oozing Britbike style.
The original Bonneville was a twin-carburettor version of the 649cc Tiger 110, running a high (by the standards of the day) 8.5:1 compression ratio and producing 34kW at 6200rpm. It got its name from the Bonneville salt flats in Utah where Johnny Allen was timed at an incredible 342km/h on a very special Triumph in 1956.
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The bike remained in production from 1959 to 1975 with gradual upgrades to 744cc and 39kW. Hinckley claims the new Bonnie is based on the 1969 version, reputedly the prettiest motorcycle yet built in Britain.
| The bike bears an illustrious name and oozes style instead of oil. | It’s built around a 790cc air-cooled vertical (and I do mean vertical!) twin with a sharply oversquare 86 x 68mm bore and stroke, fed by two Kei Him CV carbs. Although it looks like a pushrod motor, it has two overhead camshafts driven by a central chain and supposedly kicks out 45kW at 7400rpm.
Claimed torque is a more realistic 60Nm at 3500rpm.
In contrast to Nipponese parallel twins, the Bonneville is laid out with 360-degree firing order … both pistons rise and drop together and fire alternately rather than with the crankshaft throws at 180 degrees and the pistons in opposition. This gives the Britbike its characteristic easy idle and bottom-end grunt.
Transmission is by means of a conventional wet multiplate clutch and five-speed gearbox, remarkable only for its very slick shifts in both directions; almost undetectable clutchless upshifts are easy.
Outright performance, however, is disappointing. The Bonneville gets away from rest with impressive alacrity and charges up through the box on a wave of short-shifting torque but it runs out of steam in top gear.
| It’s built around a 790cc air-cooled vertical twin. | The test bike, which was well run in, took a long run to get up to an indicated 187km/h; if I had draped myself over the tank like melted cheese I might have got a few more clicks but it’s really not that kind of bike. At 205kg dry, it’s also nearly 30kg heavier than the original 650 and that also puts a damper on performance.
It’s difficult to quantify without a rev-counter (serious omission, that – real Bonnies had ’em) but the motor seems to fall off the torque curve quite sharply after the 3500rpm peak. This makes the twin a dead loss as a tourer and disappointing out in the twisties but with its lightning response and quick steering it’s actually a superb commuter, sacrilegious though that sounds.
The cycle’s parts are painstakingly conventional. The frame is a classic twin-downtube design in round steel tubing with an unremarkable rectangular steel swing arm. The only unusual chassis feature is a substantial tubular head steady running down from below the steering head, making the motor a fully stressed member and lending extra rigidity.
The suspension is much the same: 41mm conventional forks in front, devoid of any adjustment, and a pair of vintage-looking shocks complete with chromed springs at the back with the time-honoured five-step adjustment for preload.
The spring and damping rates have been chosen for comfort rather than track precision so the bike can be made to wallow disconcertingly when cornering hard, but it must be said that within the limits of the chassis the steering from the 19” front wheel is stable and precise.
The bike remains steady almost down to walking speed while the low centre of gravity lends itself to quick changes of direction.
Braking is by means of a single 310mm disc in front with a twin-piston floating calliper while the back has a natty little 255m platter; while neither stopper is authentically “period” both offer substantially better performance than the drum brakes of the day. In fact the front brake is sharp enough to induce serious front-end dive under hard braking, steepening the head angle and temporarily introducing a little front wheel instability.
The seating position is of the classic sit-up-and-beg variety; the seat-to-bars distance quite short-coupled, while the wide bars make it easy to throw the bike around at low speeds, even if the lack of wind protection makes the Bonneville a trial at highway speeds.
Triumph itself acknowledges this point; their accessory catalogue lists a beautifully made but demoralisingly expensive little flyscreen. The big single instrument is clear and easy to read (like the original Smith’s stuff but without the vintage style or chronometric twitching) and is accompanied by a bank of warning lights where the rev-counter should be.
The long, flat dual seat looks absolutely right for the period and sets off the two-tone fuel tank with its big chromed badges to perfection but it’s a little thin on padding and uncomfortably hard after the first hour; the crew might do better with a more substantial “king-and-queen” set-up but it would look all wrong and I suspect most Bonnevilles will be bought (and ridden!) on looks alone.
And looks is where this real-life retro really scores; all the details are there, from the bullet-shaped indicators to the oval CEV tail-light. The header pipes line up in classic fashion with the downtubes while the lower pipes and silencers are level with the ground - as is the seam on the bottom of the 16-litre fuel tank. It all looks just right, in the understated British idiom.
More than that, fit and finish are breathtaking, especially the almost liquid finish on the polished and chromed engine casings – good enough to win concours trophies out of the box. The paintwork is deep and lustrous, everything is firmly and very neatly mounted, and all the wiring is cleanly tucked away, effortlessly reinforcing the classic look.
Hinckley’s nostalgia chariot, with its upright riding position, impressive manners in traffic but lacklustre top-end performance, was obviously built to be ridden in dignified fashion by the gentry and not thrashed by us hooligan peasants – and that it does in superlative style. And style, of course, is what a true retro bike is all about.
Thanks to Mike Hopkins Motorcycles, Cape Town, for the test bike. The Bonneville costs R65 900.
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SPECIFICATIONS
Motor: Air-cooled 360-degree four-stroke parallel twin.
Capacity: 790cc.
Bore x stroke: 86 x 68mm.
Valvegear: DOHC with four overhead valves per cylinder.
Compression ratio: 9.2:1.
Power: 45.5kW @ 7 400rpm.
Torque: 60Nm @ 3 500rpm.
Induction: Twin Kei Hin CV carburettors with throttle position sensors.
Ignition: Inductive digital.
Starting: Electric.
Clutch: Cable-operated multiplate wet clutch.
Transmission: Five-speed gearbox with chain final drive.
Suspension: 41mm conventional cartridge forks at front, twin hydraulic shock-absorbers, adjustable for preload, at rear.
Brakes: 310mm disc with twin-piston floating calliper at front, 255mm disc with twin-piston floating calliper at rear.
Tyres: Front: 120/90 -R19 tubeless. Rear: 130/85 - R17 tubeless.
Wheelbase: 1 493mm.
Seat height: 775mm.
Dry weight: 205kg.
Fuel capacity: 16 litres
Price: R65 900.
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