Basic layout is shared with the XS250 to the extent that you can turn a 250 into a 400 by swapping over top ends. Given the large numbers of thrashed 250s around, this is a useful factor in spares acquisition because a non-running 250 can be picked up for less than £50. Basic problems with the XS concern difficult starting, quick rot suspension and swinging arm bearing wear. Engines can have the life thrashed out of them in less than 20000 miles, yet can run for three times that if given a little attention and frequent oil changes.
Typical of engines of such a simple design, fuel economy can be very good. A best of 80mpg can be achieved when pottering around, 60mpg is usually quite possible and the very worst was 40mpg against a head wind of huge proportions under full steam - such poor economy, though, was very rare. Perhaps economy is helped by the fact that the engine is so simple to maintain and things like valves stay within limits for a very long time.
Top speed is 110mph on the clock, although this requires some very favourable conditions. There are times when it’s impossible to push it past 95mph. 90mph cruising is just about possible but the cramped riding position for a tall rider makes this less than comfortable. The whole bike feels so much more pleasant at 80mph that a relatively legal pace is encouraged.
Vibration is present, especially at low speeds when the engine seems quite rough. It starts to smooth out once the revs are above 6000rpm and then starts to become bad again if you venture beyond 9500rpm. It’s hardly any worse than the complex Superdream, though not as smooth as a Suzuki GS400 but much better than a Triumph 500. The vibes don’t seem to wreck any cycle parts and at least it’s not necessary to keep looking at the clocks to find out what the engine's doing.
Extracting speed from the XS400 requires a little work and gives a feeling of accomplishment. Keeping up with a modern bike turns the ride into an exciting event as the whole plot bucks and weaves, the gearbox tap-danced to let the motor spin to the redline and the Motad takes on a soulful howl. On paper the XS could be dismissed as very bland, on the road it’s an exciting little hustler, if only because most of the chassis is dangerously worn out.
The engine has a decided knack to starting it. You can leave the keys in it and by the time you get back any thief will be so knackered that you can smash him into a pulp before handing him over to the authorities. If the points have been well set up (every 3000 miles) it’s possible to get it into life after a mere four kicks if you know the right moves and throw in a few prayers. Sometimes nasty atmospheric conditions means it’s a real bugger. Old, worn wiring might be the culprit.
One bike was fitted with electronic ignition, which for 10000 miles gave much improved starting but then it became very erratic indeed. An electric starter is fitted but it only has an effect once the engine is well warmed up useful if you stall in traffic but otherwise a waste of time. Generally, electrics were fine with none of the Suzuki tendency to burn out all the electrical components. A very neat touch were the self-cancelling indicators. Every bike should have them fitted.
Once running, though, it gives every indication of giving its all without complaint. Both bikes I have owned have had a slight oil weep between head and cylinder, but this never became worse and had no ill effects on the performance. I took my first XS400 on the continent for a tour that involved all kinds of riding, from flat out, full throttle work to crawling through town. The bike’s light mass meant it was very chuckable and the revvy nature of the engine allowed it to be thrashed without any apparent ill effects.
It must be said, though, that I favour small bikes where it’s possible to use most of the power for most of the time. People used to big tourers would probably find the need to rush up and down the six speed box a large pain... horses for courses. I find the XS great for despatching in Shit City.
The swinging arm bearings need replacing every 8000 miles sometimes this can be a real pain as the bits refuse to come apart unless violently attacked with a drift and very big hammer. Only the foolhardy will venture out in the wet as the front disc is a period piece best suited to a museum, it would take a few more years before the Japs sussed how to make discs work in the wet. The rear disc tended to lock up the back wheel when the bike was ridden solo. The front pads lasted for 10000 miles and the rear pads never seemed to wear out. The drive chain could be like an elastic band in less than 10000 miles - a great shame on such a low powered bike. Surely, Yamaha could do better than this.
Handling was not particularly good. I suspect that spending dosh on rear shocks that worked and a fork brace would solve all the problems, but I wasn’t inclined to spend more than the bike was worth on such extravagance. Even stripping down the forks and fitting new seals to stop the oil leaks seemed like a lot of hard work. The overall impression was more of shock than absorb. Riding fast with shot shocks and swinging arm bearings is most disconcerting because the bike feels like it is about to fling you off the back at any moment. Throw in some balding tyres and you can only thank god for the NHS.
Once, a rear tyre puncture with pillion and luggage aboard was so frightening that the young lady on the back left scar tissue on my shoulder as she clung on for dear life. Her sun tan seemed to have disappeared once we dismounted. It was only on long hard thrashes that I began to really yearn for a modern, stable and agile rocket ship. After hours in the seat, every lurch and wobble seems to be magnified - after a days hard ride I was often well dead.
Both my bikes had non standard exhausts fitted, which bears out the rumour that stock exhausts rot away rapidly. Motad’s two into one system suits the engine very well, although a new one costs more than many bikes. The bikes are cheap to buy. I only paid £300 each, and those were bought from dealers in relatively good condition. They can be found much cheaper than that in the private market, although a lot of them will be well knackered. I did 30000 miles on the first, putting 40000 miles on the clock. It didn’t actually blow up, just that so many different components had come to the end of their life simultaneously that it wasn’t a viable proposition to put right.
With the first bike as a spare I expect to push the second bike well past 50000 miles. The Yamaha looks just like a proper motorcycle should and represents cheap, enjoyable motorcycling and as a form of entertainment is very hard to beat for the money.
Nigel Partridge