Friday 13 August 2021

Suzuki GT550

Most reports of the Suzuki GT550 are very negative, along the lines that it’s slow, thirsty and not very reliable. Well, my decade with a 1975 model has been a happy one in which I have increased the mileage from the 10000 that was on the clock when I bought the bike to 72000 miles.

It must be admitted straight away that I am not a young tearaway - I was fifty one when I bought the bike and had been more used to a calm, measured life with British singles than the frenetic insanity of the modern Japanese four. It might be asked just what I was doing with a two stroke triple if I was used to four I stroke singles - the answer was quite simple, the GT was available, it was cheap and immaculate.

A quick ride was revelatory. Up to 5000rpm there were no vibes, the power poured in fluidly and the gearbox was as slick as could be. So this was what everyone was raving about, I thought, and I began to see why the British motorcycle was finished. The first few weeks with the bike were like starting motorcycling all over again. I had forgotten the taste of speed I had enjoyed in my youth, the Suzuki brought all the fun back into my motorcycling.

Of course, there were things I did not like at all. The front disc brake did not work in the wet, the exhaust was tinny at low revs and fuel economy was appalling after a Red Hunter 45mpg ridden mildly plunging to 35mpg. The front forks were pitted, new seals lasted a week and started leaking again. The whole front end felt loose and imprecise. I had the forks blasted and hard chromed, a quite expensive business. New seals and gaiters were then added. No more pitting and no more leaks, but the front end still felt loose.


Taper rollers bearings in the headstock helped but the single disc still caused twisting and diving. Heavy duty springs were my next try; better but still not as good as a British bike. I eventually fitted a fork brace which finally gave me the tautness I wanted.


The disc brake was an early attempt and pretty awful even in the dry, with an on-off action that I did not savour at all. I tried a couple of brands of pads over the first year to little effect. When I had the chance to buy a T500 TLS front wheel I leapt at it. What a transformation: strong, progressive braking that was so much more controllable that it reduced stopping distance. In the wet it was a real joy after the terrors of the disc brake lag. The rear drum gave no problems, just the right balance between power and feedback.


The rear shocks were still the OE Japs that allowed the bike to shake over bumps and wallow even on straight, smooth roads. A set of Girlings were bunged on and they are still there. Not so easy to upgrade were the swinging arm bearings, some kind of plastic rubbish that wore out in about five thousand miles. I replaced them twice and then shelled out for a box section Dresda swinging arm with taper roller bearings. It would be a lie to say that all these chassis modifications transformed the handling to something on a par with the best of the British bikes. The tubular frame was hefty enough to hold up the engine and absorb most of its vibes, but the way the swinging arm was attached without much support, meant the bike would still wallow and weave under mild provocation.


The top speed I’ve had out of the bike is 110mph on a German autobahn when on holiday. Vibes were finger numbing and the bike snaked along on the edge of a tank slapper. I only did it the once. It was much more pleasant at 80mph, stable and vibration free, it could hold this speed in top gear up hill and down dale, with quite strong acceleration to 95mph left in hand. Once above 5000rpm the engine took on a delightful wail - it was after all, a triple and even the GT550 could not escape from the harmonic resonance such a configuration produces.


In town the bike feels a little heavy, but with the mods could be snaked through traffic with reasonable accuracy. For town work third gear was excellent, running down to 55mph, the throttle could be snapped open and the bike take off with a speed that belied its aged appearance. These days, the clutch is a little ragged in action but after so many miles without attention I suppose it should come as no great surprise.

Ridden within the speed limits, and that’s the way I like to ride these days, the bike had entirely adequate performance and agility, only let down by the already mentioned appalling economy. Comfort, once I'd added some flat bars and modified a set of rear-sets off a proddie racer a mate used to run, was reasonable for a hundred miles at 80mph.


The seat, even with some additional padding, was not well shaped for my backside or weight, and was the first thing to intrude into my happiness. After as little as 50 miles I had to start moving my body around to relieve the pain. In the last year I've fitted a K&Q seat that looks strange but is wonderfully comfortable.


The other major problem with the bike is that many components are constructed from metal that seems to suck in water and spit out rust. Worst of all is the three into four exhaust system. Heavy enough to be of use to a weight lifter, this corrodes inside and outside despite the coating of oil from the two stroke total loss lubrication system and also leaks around the joints in the system.

At least it did until I bought a used system and took a welding torch to it. I welded up the joints, which stopped that problem but after a year the baffles had gone again. As can be imagined, GT550 exhausts are not a common sight these days. There isn't a good aftermarket choice available - not unless you want the power delivery ruined and the noise increased until all the plod come running.


After much thought I redesigned the system myself, keeping all the basic dimensions the same. The downpipes were fabricated for me in stainless steel, with stubs matched for some universal megas of the straight through variety with some modified baffles off an old Yamaha twin. After much experimentation noise and power remained at the stock level and corrosion was eliminated. I probably saved about 20lbs in weight as well!


Other items that rusted were the seat base (repaired with a GRP kit), the mudguards, the chain guard, the headlamp shell and everything else that was chromed. However, everything was simple enough to discard (indicators, grab rail) or replace with plastic or stainless steel items. The frame has been touched up whilst the tank and side panels have been resprayed in British racing green. It now looks tidy rather than immaculate, well used rather than straight from the crate. It isn’t the most beautiful thing on the road, its styling could just as easily be of the sixties as of the seventies.


The engine, though, has been a gem. Still on the original pistons and chrome bore, the top end gets a decoke every 15000 miles, the carbs, oil pump and ignition timing set every 5000 miles and the gearbox oil changed every 2000 miles. It hasn’t given any real problems, although the gearbox has become a little imprecise with age and there are a couple of false neutrals.


Consumable consumption is not unreasonable. A set of Roadrunners (which feel a lot safer than Dunlops) lasts a good 12000 miles, brake shoes at both ends around 20000 miles, only the chain and sprockets let the side down, around 6500 miles for the former and 9000 miles for the latter.
Electrics are still totally original save for a QH front light. The electric start has never worked, its handlebar switch is now an extra horn button which controls a set of air horns that frightens the life out of me.

Most of the GTs I see around are in an awful state. Because it lacks the obvious appeal of the Kawasaki triples or Yamaha twins, they tend to be thrashed and neglected - it’s this abuse I think that has given them their reputation for poor durability. Find one in good shape, look after it and treat it with respect, and I think you'll find it’s a perfectly decent motorcycle. I have no intention of selling mine for many years to come.

Adam West