The 400’s engine was descended from the earlier 350/4, itself a smaller version of the 500/4 which in turn was similar to the original sixties Honda four. The 350/4 was well known on the Continent and in the USA for its lack of power, something the 400/4 shared below 4000rpm. From there to six grand there was a hint of things to come and beyond 6000rpm it began to take off. Despite the revvy nature of the motor, the smoothness of the engine meant it could be strung along at lower revs with little complaint.
Where the little four differed from all its predecessors was its low weight, stiff single down tube frame and radical (for then) riding position with flat bars and rear-set footrests. The initial road tests of the day claimed the bike was a much needed breath of fresh air from Honda who’s range included such high spots as the mediocre CB250G5 and the outdated and heavy SOHC CB750.
In a matter of months the roads seemed full of the little red and blue things scurrying about everywhere. At that time I was riding a Kawasaki Z750 twin and I can recall being blown off down some country roads by one of them, this left me distinctly browned off that the smaller bike had disappeared quite so easily. That particular incident must have made a deep impression, because I have since bought two 400/4s. The first bike was purchased in 1980 for £650. After selling that bike three years ago, I paid £235 for another. Both bikes were blue early models with the footrests mounted on the swinging arm.
Whilst the first bike was a low mileage example in good condition (requiring little in the way of maintenance), the second was some ten years old when I bought it and was in need of some tender loving care. The second bike was purchased through MCN classifieds and although the initial appearance was disappointing a quick road test rekindled some fond memories. Both the frame and alloy were plagued by the usual Jap corrosion, although the petrol tank and mudguards were, surprisingly, still in good fettle. The bike was fitted with a new Motad 4-1 exhaust.
There were two immediate problems - the rear tyre was worn out and the kickstart didn’t. The latter problem became the cause of much hassle. Due to the poor state of the battery, and because I was loathe to spend £20 on a new battery, I decided to try to fix the kickstart myself.
Armed with my old Haynes manual and a good deal of enthusiasm I set about removing the right hand crankcase cover. After a lot of swearing and grazed knuckles I found the remains of the kickstart internals - a large spring and some gears on a small shaft which the manual said should have engaged with a gear inside the crankcase. I eventually worked out that some parts were missing. Naturally, my local dealer didn’t have any in stock.
After several trips, numerous phones calls and a lot of hassle, the parts were ordered and arrived. After assembling them the kickstart still didn’t work. As a last resort I arranged to have the bike collected by the dealer. Readers will be able to draw their own conclusions as to my mechanical abilities when I reveal that I also failed to remove the rounded off oil filter bolt.
The mechanic at the dealers soon fixed the oil filter bolt, but refused to reveal how, saying it was a trade secret (probably a big hammer and chisel - Ed). The kickstart didn’t work because part of the crankcase had broken off, but the mechanic managed to fix it up so that it worked for some of the time. To fix it properly meant a complete engine strip and new set of crankcases - which would cost a lot more than the value of the bike. The bike was also given a tune-up while at the dealers.
A new problem developed at full throttle openings - large quantities of blue smoke came out of the exhaust. This fault was not apparent before the bike had visited the dealer. I found that the mechanic had replenished the sump with an extra two pints of oil. Draining off the oil solved the problem. It was a bit worrying to find that the most basic bit of servicing had been done wrong by the so-called professionals. The previous owner had thrown in a Rickman half fairing with no fixings when I’d bought the bike. I found Rickman’s address in a back issue of MCN and wrote off a letter.
After several letters I received a polite letter and a detailed reply stating that many of the parts were available. I wrote off a £30 cheque for the bits plus a set of ace bars. Two days later a large parcel arrived. After a weekend spent trying to fit switchgear to handlebars and fairing to bike I had to admit defeat. I don’t know if this was my fault or the fault of the bits, but I later sold them for £30 in MCN.
The Honda can be used solo or two-up for more or less anything - riding to work, touring, or even as a bit of a boy racer, although it can’t compete with the LC brigade unless you bore out the Honda to 460cc and fit wild cams. Tyres and chains last well and the finish can be kept reasonable if you are prepared to put in a modicum of elbow grease. Of course you'll always find abused examples of the marque but there are still sufficient bikes around for prospective owners to be choosy, regardless of the price range. Prices range from £150 to £1000 depending on year and condition.
The problems I have experienced can be summarised as follows: the cush drive tends to wear rapidly resulting in graunching noises when the clutch engages; the gear linkage wears quickly resulting in excess movement at the pedal and difficulty in cog swapping; the front disc sticks if not maintained regularly and the swinging arm mounts are uncomfortable for pillion passengers.
Both of my bikes have been reliable, with no camchain problems and no other top end problems. The UMG has rather different views on longevity and reliability, but, whatever, the engine is a simple, straightforward unit. Valve clearances are set by screw and locknut adjusters, ignition is by good, old fashioned contact breakers, although the carbs do need vacuum gauges for correct balancing.
The Honda has a nice feel to it, in the dry braking is both progressive and smooth, the front disc and rear drum working well together. Handling is always adequate, especially with decent rear shocks. Some have predicted the 400/4 will become a collectors bike. In time this might well push up prices, particularly as machines become scarcer. However for the time being, the 400/4 represents good value for money and offers relatively sophisticated four cylinder motorcycling on the cheap.
Martin Bradley