Why Honda’s CB400 Four is a true legend
45 years ago Honda miniaturised their iconic CB750/Four, to create a jewel-like bike that’s become the UK’s favourite Japanese classic
Celebrating 45 years of the jewel-like six-speed supersport classic
While Honda’s first CB750, launched 50 years ago this year, is rightly celebrated as the first mainstream four-cylinder superbike, it is arguably its smaller spin-off, also celebrating an anniversary in 2019, which was even more significant in that it introduced a whole generation to affordable Japanese fourcylinder fun – the CB400 Four. Receiving its global unveiling 45 years ago at the Cologne IFMA Show in the autumn of 1974 and later in the UK at Earls Court, the ‘400/4’, as it’s more commonly known, was much more than just a junior version of the landmark CB750. Styled specifically for Europe as a street sportster with a sinuous 4:1 sports exhaust which remains a style icon to this day, the new middleweight also handled well, had a ‘proper’ big bike specification including a disc front brake, was the first mainstream motorcycle to have a six-speed gearbox and the latter, when used vigorously in conjunction with its 37bhp, delivered enough performance to hang onto the coat-tails of rival two-strokes such as the Kawasaki 350 S3 and Suzuki GT380 – but with far more style. In short, the CB400F was the first ‘mini superbike’ and one which, costing £669 when launched (two-thirds that of the CB750) was within reach of
a new generation of sports bike enthusiasts brought up on tales of Hailwood’s Honda six and ‘Ago’ and Phil Read’s MVs.
And yet, although over 100,000 were built, Honda’s ‘junior jewel’ was not a commercial success. Although popular, particularly in the UK, it was expensive to produce, never took off in the important US market, was updated to no avail and was withdrawn from production after only two years. Today, however, the CB400/4 is viewed very differently. As a ‘mini CB750’ it’s just as much of a technical marvel as its bigger brother but with a distinctive beauty all its own. As an object of ’70s lust it’s a time machine back to 50-somethings’ youth and as an affordable Honda with plenty of examples still available, plus an impressive spares back-up to match, it’s a great ‘starter classic’ for those for whom a CB750 or Z1 are simply out of financial reach. And yet, the CB400/4 story all started so differently…
Birth of a legend
In truth, of course, the CB400F wasn’t Honda’s first ‘junior’ transverse four at all. After the success of the CB750 in 1969, Honda had quickly followed it up with the CB500F of 1971 and CB350F of 1972, both using miniaturised versions of the SOHC, two valve, inline four layout pioneered with the CB750. Although reasonably successful globally, the 350 was never officially imported into the UK and was aimed more at the US market where it was seen more as an entry-level tourer. The UK market, meanwhile, made do with Honda’s CB350 twin, which actually outperformed the four. That all changed in 1974. With a desire to boost the profile of its four-cylinder machines but with motorcycle development capacity at the time significantly hindered by Honda’s then focus on cars it was decided to update existing models rather than cerate all-new ones; specifically, sportier, more distinctivelooking versions of both the 350 and 500 that would appeal to European sporting tastes. The CB400F and CB550F ‘Super Sport’ were the result.
With the new 400, Honda’s engineers took the CB350’s 47 x 50mm ‘undersquare’ engine and bored it out to an ‘oversquare’ 51mm to give a capacity of 408cc (although this was reduced to 398cc for 400cc ‘critical’ markets such as France and Japan). An all-new cylinder head had larger combustion chambers housing bigger intake and exhaust valves. New pistons raised compression slightly from 9.3 to 9.4:1 and a new, lightweight 4:1 exhaust replaced the 350’s cumbersome 4:4. To finish it off, the 400 also got a new six-speed gearbox
– a world first – which in turn required different crankcases. That said, many other internals, including the crank, rods and camshaft, remained unchanged – even the 350’s dinky 20mm carbs were retained. The result, raising power from 34bhp to 37bhp, although not as dramatic as perhaps hoped did, when combined with the new gearbox, significantly improve acceleration (its standing quarter time went from the high 15 second to low 14s) and give a wholly more sporty character. Besides, what the CB400F engine lacked in power it made up for with four-cylinder refinement, smoothness and class. It even had an electric starter when all the rival strokers were just ‘kick’. Just as crucially, Honda also uprated the whole style and character of its junior four. Out went the upright, US
‘The 400/4 also got a six-speed ’box – a world first’
targetted, ‘mini 750’ look of the 350. In came a sportier, almost café racer style thanks to new, more rearset footpegs, lower handlebars, a smaller, more racy, slab-sided fuel tank (complete with ‘Super Sport’ logo in case you were left in any doubt), sporty seat and that bold four-into-one exhaust. All of that, combined with a strikingly bold plain paintjob more reminiscent of an Italian racer of the era than the contemporary metalfake, stripes and badge-bedecked road bikes, added up to a true racer for the road. Yet while the CB400F caused a sensation when launched and generated universally glowing reviews, it still wasn’t quite the success Honda had hoped for. Sales were decent in the UK and reasonable elsewhere in Europe, but in the US buyers were put off by its racer posture and cramped pillion – so much so that dealers began fitting higher ’bars to unsold bikes. And despite significant success in TT F3 where 400cc four-strokes competed against 250cc strokers, and in classes where tuned and enlarged versions made the little CB into something of a giant-killer, the 400/4 also lacked the raw power and lightness of two-stroke, twin cylinder rivals such as Yamaha’s hugely popular RD350. Making a loss As a result, updates, albeit minor, came quickly. Those first 1975 bikes were simply called the CB400F, came only in plain red or blue and are identifiable by having their pillion ’pegs mounted on the swingarm. These were repositioned onto a mounting loop for 1976 when the CB also got a locking filler cap. In 1977 the F1 version was created for the US and Canada which featured a striking plain yellow tank and black side panels with a different logo. Then, in 1978, the UK and Europe received the F2 version, distinguished by its red or yellow colour options, complete with tank stripes and different badging. The yellow version in particular made the previously sober 400 a much more striking proposition.
But it wasn’t enough. Despite the 400/4’s popularity in Europe and particularly the UK, poor US sales led to it being dropped from Honda’s line-up in favour of a new generation of 250 and 400 twins – the Dream and Super Dream although another factor, lingering rumour has it, might have been in play. It’s reputed up to this day that Honda initially got its sums wrong on the little CB, failing to cost and price it correctly so disastrously that every bike built was sold at a loss (it was, after all, almost as expensive as the CB750 to produce). That error, once discovered, was the final nail in the little CB’s coffin.
But in the UK at least, that very popularity, allied to typical Honda durability and aided by a plentiful spare parts supply, has in recent years given the 400/4 a second lease of life as a ‘modern classic’. Decent examples with which middle-aged men can relive their youth can still be found for as little as £3000; virtually all parts are available from the likes of specialists David Silver Spares, who devote a good chunk of their business to the little Honda, and as a result the 400/4 remains as popular as ever with men of a certain age happily restoring examples in their garages or sheds or even buying one of the 60-odd batch-restored examples Silver recently produced. Indeed TV presenter James May was a famous example, buying one of the first Silver restored bikes in May 2012. He said at the time: “What makes it so pleasing is that it feels like it looks: sophisticated and rich in its details. I know the contemporary Kawasakis and Suzukis were quicker but look deeper and there’s a faintly cerebral quality to the 400 Four. It exhibits the appeal of a quality artefact and elicits pleasure in its contemplation.”
Today that very bike is one of the stars in Silver’s Honda Museum. As David Silver himself says: “The CB400F has to be the most popular Japanese classic in the UK. It’s the volume seller for us.” Not bad for a bike which was something of a failure when launched.
‘It’s the most popular Japanese classic in the UK’