Memorable Motorcycles Honda CB400

November 6, 2008
Frank Melling
Frank Melling
Contributing Editor| Articles|RSS

Our Memorable Motorcycles expert, Frank Melling also is the organizer of the British vintage motorcycle extravaganza known as Thundersprint. Melling began riding five decades ago and remains as much in love with motorcycles as when he drove his first bike into a cow shed wall aged ten. In the last 50 years, Melling has competed in every form of motorcycle sport and now declares himself to be too old to grow up and be sensible.

Honda CB400F1
Thanks to reliability and spunky nature, the Honda CB400F certainly qualifies as a successful Memorable Motorcycle.

I have been riding motorcycles for a long time and, fortunately, I have not lost any of my passion for bikes. I have ridden an awful lot of good bikes, a few mediocre ones and the occasional two-wheeled horror story but a few, rather special, motorcycles are truly memorable. One of these is the Honda CB400F1 which simply makes me smile with the memories of one of the nicest motorcycles ever to grace a highway.

The CB400 isn’t perfect but it is such a thoroughly good motorcycle that even its worst enemy would find it hard to say a word against it.

The CB400’s dad was the technically brilliant, but rather dull, CB350. A story about this bike – allegedly built at the behest of Sochiro Honda, who felt that a 350cc motor was the perfect size for a four-cylinder road bike – appeared recently in “Memorable Motorcycles”.

The problem was that whilst “Big Daddy” Honda loved the 350 – paying customers didn’t. This is not surprising since the 350 “4” was slower, heavier, more expensive and cost more to build than its twin-cylinder brother, the 325cc CB350 Dream.

In essence, the 350 “Four” was just too well-behaved a motorcycle. It brushed its teeth every morning, combed its immaculate hair, always wore clean jeans, which were freshly ironed, and only drank one can of beer on a Saturday evening. As your accountant it would have been fine. As a friend to party with, it was a disaster.

Honda’s answer was elegantly simple. The 350 “Four” was a fine motorcycle. It just needed some help to come out from behind the door and reveal its true potential.

Honda CB400F1
Using its CB350 as a base, Honda bored out the four-cylinder powerplant to up to 408cc.

The first job was to take the 350’s powerplant to the gym. Incredibly for such a sophisticated motor, the 350 was undersquare at 47mm x 50mm. Honda bored the new motor to take a 51mm piston which gave a marginally over square engine with a capacity of 408cc. They fitted new, bigger valves than the 350 plus a stronger clutch and a four-into-one siamesed exhaust system, which both increased torque and looked cool.

A sweet, close-ratio, six-speed gearbox meant that the motor could be kept on the boil and the delightful howl from the long, tapering silencer took us Grands Prix wannabees right back to the golden days of Honda racing with Jim Redman and Mike Hailwood.

The end result of Honda’s re-engineering was a bomb proof engine which gave a very healthy 37 hp @ 10,000 rpm – equivalent to around 100mph with a small, light rider tucked in tight on the fuel tank. This needs putting into perspective. 37 hp was slightly more power than a good 350cc Aermacchi or AJS 7R produced – and these were still competitive in Grands Prix four years earlier.

The chassis remained more or less unchanged in terms of being small and light but cosmetically the new bike was very much a sportbike. The flat ‘bars, narrow tank and seat and, most of all, an engine which positively demanded to be revved, all pointed to hard riding.

Honda encouraged the Cafe Racer image that the CB400 inculcated and this was both good and bad in terms of sales. The firm suspension and high-revving engine did not endear the bike to American riders, and the USA, even more so than now, was the critical market for Honda.

By contrast, European riders, with road-racing genes running through their bodies, loved the CB400. With the beautiful little power unit howling between 6,000 rpm and the redline at 10,000 plus, the Honda was a true racebike for the street. Hammered through rough corners, the firm suspension was in its element and best of all, it flattered the rider – regardless of his ability.

Honda CB400F1
It may not have been the fastest bike in its day, but the Honda CB400F did perform well and won over many a rider.

Only the brakes were less than ideal, but with four-stroke engine braking available, this was not a problem in the real world.

The 400 “4” was never going to beat the killer quick Kawasakis of the day, but it was an infinitely more refined and sophisticated motorcycle and one which won the hearts of all who rode it.

Today, CB400s are still recognised as outstanding motorcycles and this is a problem for would be owners. On one side of the coin the 400 is a mass produced motorcycle with no racing pedigree or exotic bloodline. It is, however, one of the nicest motorcycles ever built. The end result is that it will take a solid $5000 to own one of the best examples of these lovely little bikes – although considerably less will buy you a running, but un-restored example.

Post Script:

I got to know the CB 400 on a rather more personal level than I would have preferred. My College degree was as a teacher and I majored in English Literature. In English schools of the day, kids with a leaning towards Fine Arts never went near an engineering shop.

However, I had raced bikes from the first time I could afford an entry fee and had become reasonably proficient at gas welding simply because in those far off days bikes broke all the time and needed mending.

Colin Wilkinson, a long time friend of mine, was a good national class racer. He had campaigned a very fast Norton for many years but even by his tolerant standards was weary of it breaking. In August 1975 Colin purchased a brand-new CB400 road bike with the intention of riding it in the 500cc class of the Manx Grand Prix held over the incredibly tough Isle of Man TT course.

Honda CB400F1
How reliable was the Honda CB400? Our writer’s friend used it as a commuter and a Isle of Man GP racer!

He arrived at my house with the bike having covered about 5 miles from new and asked that I cut and re-profile the exhaust pipes so that they tucked tight against the frame and fabricate a meagphone exhaust. The little Honda sat there with its chrome exhausts gleaming and I began to feel like the vet approaching the happy looking stallion which was about to have its life changed.

Fortunately, I got the cuts right and doubly fortunately none of the welds broke during the killer tough two weeks of the “Manx”. I would never claim to be a master craftsman but when it came to welding my work was always durable.

Colin made a few basic modifications to the Honda and raised the gearing slightly. These mods, plus Colin’s riding ability, were enough to give an 88-mph lap in the “Manx” and that was with the frame, suspension and motor completely standard.

Colin used it again in the “Manx” and then sponsored another rider who finished 8th in the Production TT. In between, the CB400 was used as a commuter bike and for recreational riding.

10,000 miles later, the Honda was sold – still running perfectly and, except for checking the valve clearances, with the motor completely untouched.

That’s why riders loved the CB400!

Thanks to Bonhams Auctions for the loan of the CB400 in this article. Bonhams may be contacted at or telephone (415) 861-7500