It's hard to say why Suzuki didn't officially import their 650cc vertical twin. They had a good reputation for such devices in the GS450 and GS500E, the 650 more of the same kind of engineering finesse. The model I came across was a 1984 item in reasonable nick for a 23000 miler. 651cc of DOHC vertical twin butchness that was mildly tuned by Japanese standards - a mere 53 horses at 7000rpm.
Unlike many efforts at producing the definitive vertical twin, the mass was a relatively mild 390Ibs, though the custom stance destroyed any pretensions to sportster fame. It was very comfortable to leap on to for the first time and lurch around town, but a bit of open road work revealed maximum stress in arms and thighs. The engine whirred away efficiently but never came close to delivering an excessive amount of low rev torque, ran best in the 5000-8000rpm range. If there was nothing mind blowing about the mill, neither was there any element that disturbed.
At least until I tried to use the front disc in anger. The bike was old, the calipers may not even have been original fare so these comments need not necessarily apply to all GRs. Basically, the discs were prone to sticking on and seizure, especially when there was a bit of damp in the air. After one particularly vivid emergency stop, the front brake locked on solid! Leaving me to drag the bike backwards into the gutter to avoid the anger of the cagers!
A couple of tentative kicks didn't do any good, and an outright aggressive booting merely hurt my toes and almost caused the bike to fall over. Loosening the bleed nipple allowed caustic brake fluid to splatter right into my face! After some very vicious bouncing of the forks whilst working the brake lever, she finally freed up. A GS500E caliper was fitted with used Goodridge hose. Stopped the seizing up but needed an awful lot of muscle to make the tyre scream.
The rubber was old Japlops that made the bike feel a bit quirky in the dry and just like an old MZ on original Pneumats in the wet. Which is to say bloody dangerous. The breaker was consulted, some used Michelins fitted. Made the bike much more fun to ride in the wet and dry. These were down to about 4mm, took just 4500 miles to get them down to the carcass, which again made the handling a bit dodgy. Though it could skate and skid around it was still quite controllable, and the chassis was so well sorted that the mild weaves never developed into terminal wobbles.
The only problem with the handling came from the sogginess of the original suspension. Not from twitchiness but from lack of ground clearance. The stand's prong and the exhaust's brackets could all dig in. In the dark an interesting spark show resulted, but once of twice something caught in the tarmac and the whole bike tried to pivot around. The high, wide bars gave an unusual amount of leverage that allowed me to force the bike back on to the straight and narrow but my pillion thought that the end had arrived.
Top speed wasn't much more than the ton but if I'd fitted flat bars, and pegs to match, I'm sure the old girl could've been re-geared to hit the ton-ten, or maybe a bit more. To be honest, much beyond 70mph was something of a strain on the shoulder muscles but useful to have the power there to accelerate out of trouble. Vibes at 70mph were a gentle thrum that didn't really worry me - the bike shook more below 3000rpm; only imitated an old British troll when thrashed beyond eight grand. Pretty pointless as, by then, power had completely dissipated.
70-75mph cruising was dictated by the high bars but though the engine was smooth it didn't feel exactly relaxed. The gearing could've been much taller in top, as it was I was always trying to change up to another ratio and I could actually pull off quite smartly in third gear. I did go as far as taking the engine sprocket cover off but there wasn't much room to fit a larger engine sprocket, which would probably have helped with the chain as it always needed adjusting. The gearbox, itself, was very slick and the clutch needed very little effort, though it would sometimes drag after excessive town riding - especially if the 1000 mile oil change wasn't far off.
After about seven months the frame became splattered with rust. I took the tank and seat off, found it even worse where it couldn't be seen. Not really wanting to whip the engine out, take the bike right down, I did the best I could, patched it up with black Smoothrite. That was how I discovered that a past owner had bodged the electrics with a car rectifier and regulator. These were meant to reside inside an alternator and were somewhat exposed to the elements. The electrics worked OK, even if the lights were pretty mediocre and the electric boot grumbled on a cold morning.
Suzuki electrics, of this era, are a bit notorious, the usual fix a Superdream rectifier/regulator but used ones in good nick are, these days, rare on the ground. Perhaps foolishly, I decided components out of a GSS500E would do the job. After a bit of head scratching regarding the wiring - different colours - I got it all back together. Only to find there was a strong smell of burning after about five minutes. I put the old components back in and, luckily, it was fine. The used GS500 stuff may've been burnt out already, can't think it wasn't up to the current.
Riding through winter had the front disc gumming up, the drive chain threatening to disintegrate and yet more rust coming out from under the paint. The mild speeds involved meant that fuel went from 55 to 65mpg and the tyres lasted about fifty percent longer. The engine's lack of violent power and torque, with the smooth running transmission, combined with the safe handling, meant that it was a breeze to ride through even the most atrocious conditions.
Some black ice tested my reactions a couple of times, the wide bars and low mass allowing for good control.
The engine alloy and wheels took a real battering from the awful weather, left deep in immovable corrosion, but the rest of the minor problems were easily sorted. The new riding season was greeted with a mill in good shape despite the 35000 miles - I never did the valves, balanced the carbs twice but changed the oil often. The latter by far the most important bit of maintenance on Jap bikes.
This was a good bike but it was missing the fiery heart of a similar sized British twin and in the end this decided me to move on to pastures new. A good trade-in price for a new but heavily discounted Moto Guzzi 1000S - a pagan beast that seemed plain awful for the first few hundred miles but you do get used to them. The GR would make a good second bike!
Harry Stephenson