My Suzuki GT550, a fat boy two stroke triple, receives all kinds of nasty, snide comments from people who think they know the whole story without even slinging a leg over the evil little piece of slime. The bikes have such a poor reputation that they can be picked up for next to nothing and I've a garage full of both 380 and 550’s for cheap spares. Just to confuse the pundits, the bike looks stock at a quick glance, the only obvious modification, the junking of the gargantuan three into four exhaust. The inevitable spannies are offered as evidence of my anti-social status.
And, of course, a vindictive layer of exhaust emissions which varies between the tolerable and the choking. The former when it’s used in the mid-range under acceleration, the latter when it’s spent too much time below 2000rpm in town. This despite the separate oil tank and metered delivery by the oil pump. There are a long list of two stroke horrors that have four stroke owners thankful for their choice of machine, including short spark plug life, massive oil consumption and dubious longevity of the engine internals.
What makes my triple special is the race tuned ports, carbs and exhaust. The stock engine gives a pathetic 40hp from 543cc - it's a sluggardly beast that can’t keep up with 400 Superdreams but goes through petrol like a GSX1100 ridden in the red. My motor’s tuned so that it hardly runs below 5000rpm, then comes in with H1 ferocity and the kind of exhaust screech that drowns out passing aeroplanes. It’s possible to rev past nine grand but only if you're not worried about returning home with a crankcase full of main bearings.
I've had great fun waiting sedately at the lights, then letting loose with the throttle, doing a hundred yard wheelie out ahead of my shocked victim, whose life is significantly shortened not just by the angst but also by the lung fulls of exhaust gas he has to eat. Lovely. Acceleration can be vicious enough to throw pillions off the back! Top speed is more than 125mph, but I find that’s a reasonable point to back off to ensure engine longevity. There's also the question of the vibes. which are frenzied above 7000 revs, bad enough to break exhausts, crack engine mountings and leave my teeth tingling for an hour afterwards.
A stock bike wouldn't have been easy to ride at those kind of speeds, especially after a little wear had got into the marginal OE suspension. I'd gone so far as to replace the front end with an early GSX550 offering, place Girlings and a hefty aluminium swinging arm out back, and finished off the whole job with some extra bracing around the headstock and swinging arm. The GT550 frame has a passing resemblance to the GT250’s, which explains a lot of the original horrors.
I went to so much trouble because the first time I tried to do 80mph on a tired stock bike it let loose with the biggest tank slapper I’ve ever experienced. I was flicked every which way completely out of control. Somehow, reacting instinctively, I lost a lot of the speed before rolling off the road. The GT's stability is not an object lesson in perfection on good tarmac. On gravel then grass it slewed all over the shop until the front wheel dug in.
I was thrown clear and most of the bike’s momentum was lost in snapping off the forks. Even if they had survived entirely intact I would've still replaced them with something better (which isn’t hard, almost anything is an improvement). The AA man was not overjoyed to have to help excavate the 450Ibs of broken metal, nor by the stink of vomit which had coated my lid and jacket after I'd thrown up.
After the remedial chassis work handling was still not outstanding, the frame geometry and weight distribution saw to that. There were weaves, a hell of a lot of effort needed to swing her through bends and some violent reactions to large road bumps. However much the chassis protested, the shakes never went berserk, they always died down as soon as the road levelled out or a bit of speed was lost. After a months worth of caution I began to explore the bike’s limits without going into a shaking fit every time the speedo closed in on 80mph!
A major limit on cornering was the ground clearance. I'd cut the stands back, on the stock bike they used to dig in, sending shudders through both the chassis and my mind. It was the exhaust that dug in now, a result of the bulky expansion chambers and a lack of room underneath the engine. The GT rode an inch higher on the revised suspension, but still managed a flurry of sparks whenever I tried to show a more modern bike who was boss on the curvy roads. It wasn’t dangerous as it just wore a hole in the silencers rather than trying to throw the bike off the road. I did try some other spannies, which opened out further along the downpipe but they lost a lot of the motor’s urge.
With the much modified engine and exhaust the GT550 had lost the impression of being as bland as white bread. Instead, it no longer liked to cruise at a constant speed, only really working when used above 5000 revs in anger. Held, at say 6000rpm, it'd stutter and try to surge up and down the rev range. It was even poorer below 5000rpm, the total lack of power meaning it'd only work in first or second, where it made such a racket that | was likely to be stoned by pedestrians. Excessive use of the gearbox was always necessary, whether out on the open road or in traffic.
That all made town riding very interesting, with the choice of coking up the plugs or running around on one wheel at insane, ever increasing velocities. The former led to frayed tempers as I had to do a plug swap, the latter with half the town’s cops coming after me. Luckily, the traffic was so congested that I usually managed to lose them, although one BMW mounted plod did eventually roar up alongside. He let me off with a warning, but said he’d book me next time. I changed my route rather than the exhausts.
Clip-ons, halfway down the fork legs, placed some extra weight over the front wheel, which cut down the wheelies to a more acceptable level and allowed me to use the excellent front GSX discs. The original front disc was a truly puny item that led to open warfare in the wet and I enjoyed smashing it to smithereens once I bought the GSX front end. In fact, the GSX discs were so powerful that in emergency stops they would shake the whole bike and cause me to think the frame was breaking up. The GT would pull up in a more or less straight line so I taught myself to ignore the shenanigans. A bit of care had to be used in the wet, as the Avon tyre would try to slide away from the bike.
With the clip-ons, the riding position became very tiresome after 30 minutes. The seat was original, the foam had sagged and an excess of weight was put on my backside from the forward mounted pegs. A 100 miles in a day had me staggering around like an arthritic pensioner, but that was OK as the GT was mostly used for the short haul to work and occasional back lane bashing.
It was too expensive to take very far. 100 miles would need three gallons of petrol, two pints of oil and a new set of spark plugs. Bits didn't fall off between 500 mile services, though they might crack up. Servicing consisted of a carb balance (30 minutes) and ignition timing (60 minutes), the latter involving a lot of cursing as a strobe was needed. Failure to service the beast every 500 miles resulted in an engine that refused to start for half an hour; then it would try to put some holes in the pistons.
Biowing head gaskets, knackered rings and stripped head studs were all too common engine maladies. Less frequent were wrecked engine seals, knackered crankshaft bearings and shattered pistons. The enlarged ports gave the rings a particularly hard time, lasting less than 2000 miles. Major components all tended to wear out together, necessitating a major engine rebuild at 8 to 10000 miles. Exchange crankshafts are still available.
The gearbox was supposed to be marginal but in 26000 miles I never had any complaints from mine. It wasn’t exactly slick but was nowhere near as vague as a similarly aged Honda. It was all part and parcel of the experience. For the money you won't find a faster, nastier set of wheels, nor a much rarer one as I seem to have most of the others in my garage.
Dennis Isles