Honda CB 400F

 

 

 

Make Model

Honda CB 400F 

Year

1977

Engine

Four stroke, transverse four cylinder, SOHC, 2 valve per cylinder.

Capacity

408 cc / 24.8 cu-in
Bore x Stroke 51 х 50 mm
Cooling System Air cooled
Compression Ratio 9.4:1
Lubrication Wet sump

Induction

4x 20mm Mikuni carburetors

Ignition

Battery and coil 
Starting Electric & kick

Max Power

37 hp / 27.5 KW @ 8500 rpm
Max Toque 24 ft-lb / 32.5 Nm @ 7500 rpm

Transmission 

6 Speed 
Final Drive Chain
Clutch Wet multi-plate

Front Suspension

Telescopic forks

Rear Suspension

Dual shocks preload adjustable

Front Brakes

Single 267mm disc

Rear Brakes

160mm drum

Front Tyre

3.00-18

Rear Tyre

3.50-18
Instrumentation

Speedometer with trip, Tachometer, Oil lamp, Neutral lamp

Wheelbase 1355 mm / 53.3 in
Seat Height 790 mm / 31.1 in
Ground Clearance 150 mm / 5.9 in

Wet Weight

185 kg / 407 lbs

Fuel Capacity 

14 Litres / 3.7 US gal
Fuel Consumption 49.7 mpg
Standing 1/4 14.71 sec @ 86.04 mph
Acceleration 0-60 6.70 sec
Top Speed 103 mph

The 750 Honda four-cylinder, which appeared in 1969, was the first in a vast range of fours from the giant Japanese company. Although most were upwards of 500CC, one model was marketed using an engine of 350CC mounted in a chassis that gave it an appearance similar to that of the 360 twin. More successful than that early 'small-four' venture, however, was the CB400 which was granted Super Sport nomenclature by the company. Like its larger stablemates, the 400's power unit is an across-the-frame, single-overhead-camshaft, four-stroke engine which, in its later modified F2 guise, produces 37bhp at 85oorpm. In fact, breathing through four Keihin carburettors, the engine will rev freely right up to its io.ooorpm red line with no fuss, and a formula one car like shriek replacing the usual smooth clock like whirr of the motor.

The power is transmitted through a six-speed gearbox which may seem rather extravagant, but which in reality is very necessary, for the bike thrives on revs and is not that powerful lower down the engine speed scale. For instance, if the bike is cruising at 7O-75mph in sixth gear and the rider runs into a strong headwind or starts to climb a motorway hill, the bike will lose pace fairly easily, thus necessitating a change of gear. This is even more pronounced when riding with a pillion aboard.

However, if the engine is kept spinning at a high rate, the 400 is turned into a very quick machine with a top speed of i03mph and a standing start quarter mile time of I5secs dead. With such an efficient little engine, fuel consumption is excellent with over 5ompg being attainable under most conditions.

The frame of the 400 is an interesting design with a single downtube running from the steering head through the centre exhausts where it is split into a cradle that winds round under the crankcase. It looks and is very sturdy and gives the bike very taut handling qualities. This is helped by the fact that all the considerable 3951b weight is kept low. Smaller riders will find that the little machine is very easy to handle in traffic and to put on and off the centre stand.

Unlike most other Japanese bikes, the CB400F2 has not been overburdened with unnecessary braking and retains just a single disc at the front and a drum at the rear; the front disc has a neat cover incidentally which keeps out a great deal of water in the wet.

Unfortunately, Honda decided to stop production of the 400 four, as the buyers in the large American market really wanted easy-to-maintain twins. The European market thought that this would be a retrogressive step, so the fours were snapped up from dealers in the hope that they would be collectors items when the twin Dream series arrived. However, sources in 1978 suggested that a completely new range of small fours would be built along with the twins, using twin-overhead-camshaft engines and ranging right down to 250CC.