The Honda CB450 is a standard motorcycle made by Honda from 1965 to 1974 with a 180° DOHC straight-twin engine. Producing 45 bhp (some 100 bhp/ litre), it was Honda's first "big" motorcycle, though it did not succeed in its goal of competing directly against the larger Triumphs, Nortons, and Harley-Davidsons in the North American market at the time. As a result, Honda tried again, leading to the development of the four cylinder Honda CB750 that marked a turning point for Honda and beginning of the "superbike" era of motorcycles.
Design The CB450 had a distinctive chrome-sided fuel tank, and shared Honda's 'family' styling found elsewhere on the S90 and CD175. Early models were known as the 'Black Bomber',Motor Cycle, 17 February 1966. Colour centrespread official Honda CB450 UK advertisement. "Meet the big black bomber..." "£360.0.0" Accessed 2013-08-22 or 'Dragon', but in Canada the K1 model was marketed as the 'Hellcat'.
The four-speed K0 model was updated in the K1 model produced from 1968 with a redesigned fuel tank, rubber-gaitered front forks instead of sliding metal shrouds, a five-speed gearbox and twin speedometer and rev-counter instruments mounted above the headlamp.Motorcycle Mechanics, January 1968, pp.19-20. Full Chat by John Day. Five speed 450 Honda Accessed 2015-06-01
Later developments progressed through a series of 'K' models with various improvements and styling changes including a single front disc brake, continuing to K7 versions in some markets, until the introduction of the CB500T in 1975.Bike, October 1975 pp.18-24 500cc Giant Test Accessed 2015-06-01
Release The Mk.I 'Black Bomber' was first shown in UK during the Diamond Jubilee Brighton Speed Trials of September 1965, traditionally held along the seafront. The bike was newly imported and its engine was not run-in, yet in a semi-competition demonstration sprint, the CB450, ridden by Allan Robinson, MBE Allan Robinson, MBE. Obituary Retrieved 2013-08-23 (a Honda staff member), achieved a standing-start kilometre time of 30.1 seconds and a terminal speed of .Motor Cycle, 16 September 1965, p.424. Brighton Speed Trials results. Accessed 2013-08-23 Afterwards, the CB450 was exhibited at a motorcycle show at the Brighton Metropole Hotel exhibition centre.Motor Cycle, 9 September 1965, Brighton Show Edition. 'Honda, Stand 15'. "This is what we've all been waiting for—the sparkling new 444cc Honda CB450. Its on show for the very first time in England". Accessed 2013-08-24
In December 1965, the UK magazine Motor Cycle reported that UK sales were planned from February 1966, its price of £360 being the equivalent cost to a conventional British 650cc pushrod parallel-twin.Motor Cycle, 9 September 1965, Brighton Show Edition prices in GBP for 1966 range: Triumph Bonneville 650 £349, BSA Lightning 650 £355, Matchless G15CSR 750 £370, Norton Dominator 650SS £361, Norton Atlas £369. Accessed 2013-08-24
In a further publicity event, Honda (UK) entered Mike Hailwood as one of the riders in the Motor Cycle 500 mile production race at Brands Hatch during July 1966. However, Hailwood was able to complete only some demonstration lapsMotor Cycle, 7 July 1966. p.22/23 Scratcher's Marathon. Motor Cycle's 500—mile race. "A plane was specially chartered to fly riders back from the previous day's Dutch Grand Prix. One who took advantage of this was Mike Hailwood and here [pictured] he brakes as he completes demonstration laps on a Honda CB450 before racing begins" Accessed 2013-08-21 on the CB450 before racing began, as it was barred from competing in the 500cc category, because the FIM had deemed that it "could not be classified as a production machine as it had two overhead camshafts"!Motor Cycle, 19 May 1966, p.664 Racing Line by David Dixon. "The Honda CB450 is not yet regarded as a 'production' machine...the CSI decided not to change the rules—under which machines with two overhead camshafts are barred—as it would be 'unfair to make a chance in mid season'.". Accessed 2013-08-21
Although the CB450's sales never matched Honda's expectations, the bike had excellent engineering for the time, including reliable electrical components, an electric starter, and a horizontally split crankcase, all features distinct from current British twins. A radical feature was the valve springing: instead of the conventional coil springs, it used 'torsion bars' – rods of steel that twisted to provide the spring effect.
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