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Honda CB 450K

 

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Make Model

Honda CB 450K

Year

1973 - 74

Engine

Four stroke, parallel twin cylinder, DOHC, 2 valves per cylinder

Capacity

445 cc / 27.1 cu-in
Bore x Stroke 70 x 57.8 mm
Cooling System Air cooled
Compression Ratio 9.0:1

Induction

2x 32mm Keihin carburetors

Ignition 

Coil with auto-advance, twin contact breaker
Starting Kick

Max Power

45 hp / 32.8 kW @ 9000 rpm

Max Torque

37.4 Nm / 27.6 lb-ft @ 7000 rpm

Transmission 

5 Speed 
Final Drive Chain
Frame Tubular semi-duplex cradle with single front down-tube

Front Suspension

Telescopic forks with two-way damping.

Rear Suspension

Swing arm, shock absorbers with adjustable preload

Front Brakes

Single disc

Rear Brakes

Drum

Front Tyre

3.25-19

Rear Tyre

3.50-18
Wheelbase 1300 mm / 53 in
Dry Weight 187 kg / 412 lbs

Wet Weight

204.0 kg / 449.7 lbs

Fuel Capacity 

14 Litres / 3.7 US gal
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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', or 'Dragon',4] but in Canada the K1 model was marketed as the 'Hellcat'.

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 (a Honda staff member), achieved a standing-start kilometre time of 30.1 seconds and a terminal speed of 100 mph (160 km/h).Afterwards, the CB450 was exhibited at a motorcycle show at the Brighton Metropole Hotel exhibition centre.

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.

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 laps 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"!

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.

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.

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.

The basic engine was modified and installed in the Honda N360 car and the exported N600, the precursor to the Honda Civic.