When it first appeared in 1977, the GS400 was hailed as a civilised, modern vertical twin with none of the self destruct habits of the old Brit stuff. The DOHC, 180° crank engine had a single gear driven counterbalancer to take care of the inherent vibration problems - it was so effective that it made the motor appear very remote, and along with suspension that totally insulated the rider from the tarmac, soon gained the bike a reputation for blandness out on the street.
And then there were the engine problems. Nothing too major, I suppose, but enough to make people think twice about buying one. The most persistent problem was exhaust valves that burnt out This happened gradually, so there was plenty of warning, but could afflict the bike with just ten grand on the clock.
With a little more mileage (say fifteen grand) the automatic camchain tensioner could stop working, breaking the camchain. By twenty grand it was not unknown for the bike to either seize or be in need of a rebore. That said, some owners were able to run the things to over forty grand with nothing more than a regular oil change and some perfunctory maintenance.
So where does that leave us? Down to assessing how the owner had looked after the bike and recalling that this was one of the first Suzuki four strokes (they had decided to give up trying to make two strokes behave like four strokes and make the real thlng). The bike ran to '79 and later models are a safer bet than those from the first year.
So how does it go? New, handling is neutral and stable but very remote - I could never feel happy on the bike, especially in the wet, but I never fell off, so no real problems. The shocks are the first of the suspension components to stop trying. As little as six grand would knock out the damping. By twelve grand the swinging arm bearings are shot and by twenty grand the front forks have lost both damping and precision. Despite all this, the bike is still rideable, thanks to a rigid tubular frame, but it tends to cut across traffic on a trailing throttle in a bumpy curve and weave a little on 90mph motorway jaunts.
Particularly bumpy roads are an excellent way for the overweight to slim as the GS will leap and bounce all over the road; it requires both muscle and very energetic manoeuvring to keep the bike in line. Throw on some decent shocks, new swinging arm bearings (usually quite a tedious job) and a decent set of tyres, and the GS will regain some of its former precision. New fork seals and thicker oil help the forks, but there's nothing much you can do about the sloppiness.
The single front disc has plenty of power but, again, lacks any feedback. Long term owners will tell you that there is some feel there, it just takes some time and effort to recognise. Riding a bike with thirty five grand on the clock revealed a disc that grabbed, locked in the Wet after a few seconds delay, didn't have much power and made some nasty noises. All conditions that wouldn't happen with a good drum after a similar time or mileage (yawn, yawn).
The power knocked out by the engine is, well, er, pretty bland. It's much more exciting to ride an old British 500 twin where every ounce of power shakes its way through the whole chassis. None of this on the Suzi, just smooth, smooth power unruffled by even a power step. The thing will cruise between seventy and eighty five all day with barely a need to shift up and down the box. Try going any faster, though, and it needs some swift clutchless action between fourth, fifth and if you're very lucky and optimistic, sixth - it will eventually make it past the ton to 105mph.
Once past thirty grand, the balancer gear train does wear and vibes increase throughout the rev range, but particularly at 70mph in fifth... the gearbox is typically Suzuki slick from new and stays the same for the first twenty five thousand miles, or so, then the change gradually becomes less positive as the selector wears until by forty grand there's a fifty-fifty chance of finding a false neutral on many bikes. Gear primary drive and wet multi-plate clutch are trouble free, as is the roller bearing crankshaft.
Fuel economy was pretty good, as much as 70mpg with mild (read legal) use and as little as 50mpg when thrashed. It averages out somewhere around 60mpg. As the bike gets older it does need regular top-ups to the oil in the wet sump between 2000 mile oil changes. It can be down to the lower level in as little as 300 miles. Not so clever.
The silencers fall apart after three years but the engine will run with anything that looks vaguely the right shape. The state of the paintwork depends entirely on the amount of care and attention lavished by the owner — there are still some very nice examples around, there are also some right pigs. It had some very mild looks ten years ago, these high tech days it's beginning to look quite quaint in an almost classic way.
Compared to other four hundred twins of the same era, the Suzi is up there with the Honda Superdream in the handling stakes (more feel from the Honda), probably the most reliable of the bunch but significantly slower than the Honda (until its balancer chains wear out, anyway) and the smoothest twin around.
The later 425 and 450cc versions are rather more reliable and durable (with the exception of valve wear on the eight valve GSX) but, of course, cost more money. The GS 400 costs as little as £150 for something that runs but looks like a holocaust survivor and as much as £400 for a one owner low mileage job with plenty of life left. For £250 to £300 it's possible to pick up a nice example that
won't immediately explode.
As tyre, chain and pad wear are all reasonable (by Jap middleweight standards) and fuel economy is good, the thing can be run on the minimum of money. Oh yes, the alternator and rectifier can and do burn out in typical Suzi manner, but it's cheap enough to repair with nonstandard parts.
The GS400 is not mechanically perfect — not as reliable as the 550 fours, for instance but it is straightforward, easy , to work on and fairly cheap (thanks to breakers) to repair when it does fail. If you really thrash and neglect your bikes it's best to avoid this one, if you do some kind of maintenance occasionally and don't burn around flat out everywhere it'll probably be a fine little machine, but if you're used to the handling qualities of British bikes you're going to find this a little unnerving because just so remote. If I had little money and could find a good one, I'd be tempted.
Bill Fowler