Friday, 15 December 2017

Wrecking Manoevres: Suzuki 550 Katana


The usual long term test tends to just graze the surface because it is so far removed from the everyday reality of running a bike in 1986. A huge segment of the market can't even afford regular oil changes let alone proper maintenance, so we wanted to run a bike for a high mileage with the minimum of expense. The bike had to have enough power to make life interesting, but not so much that it consumed petrol, tyres and chains at an alarming rate. 550s have long managed a reasonable compromise between power and conspicuous consumption, although many of the latest models have been honed dangerously close to the bone in the search for maximum power and minimum mass.

Because of the kind of neglect we intended to inflict, the engine needed a remarkable degree of inner strength and durability, which quickly narrowed the field down to Kawasaki and Suzuki. We opted for a 550 Katana because it looked so pretty, only cost £650 for an '82 job, and had an engine with a reputation for reliability second to none.

Katanas are based on the Stock Suzuki GS550 with a flash set of clothes, rear sets, stiffer suspension and a longer wheelbase marking most of the significant changes. The bike we purchased was standard except for a black front mudguard and non standard clocks, indicative of some previous crash damage. First impressions were of a stable but heavy machine. Power wasn't exactly stunning but the bike was happy enough buzzing along at 90mph. The twin disc front brakes were very powerful, but insensitive enough to lock the front wheel at low speeds, not very funny when going around corners as this flicks the front wheel back to the vertical without any warning. The rear single disc brake was no better or worse than a good drum brake. The Katana is more exciting to look at than to ride, but the strength of the engine saves it from instant obscurity. Eat yer heart out Honda owners.

The non original speedo showed eleven grand and the engine looked and sounded as if that mileage might be reasonable. The bike was used for commuting around Shit City and for running back and forth to Wales over the weekend, encompassing a wide range of traffic and road conditions. Most of this riding occurred during what was laughingly referred to as the summer. For those who can bear to recall '85 this meant rain and more bloody rain, which at least meant the bike was subjected to enough nastiness to test the quality of the paintwork and engine casings.

The first problem was the silencers. These black chrome jobs still looked fine on the outside but most of the baffles had rusted away enough to turn irate heads when the bike roared past. For sure, this was mildly antisocial but nowhere near as bad as those nasty capitalists who wanted several hundred quid for a replacement set. As the engine only knocked out 54BHP it was not too dependent on perfect silencers, and at least blind car drivers had a chance to hear the bikes' approach. After 5000 miles, the bike had developed a straight through exhaust system that eventually made enough noise to cause instant headaches for anyone within a mile of it. Performance was affected when the end plate of one silencer fell out and the silencer cracked around its circumference. A new end plate was produced from a biscuit tin and secured with self tapping screws and Gun Gum. Two Jubilee clips secured another piece of tin around the silencer, producing a surprisingly strong solution to the problem of the cracked silencer. Everything was given a quick coat of heat resistant resistant matt black paint to discourage the attentions of Mr. Plod, who was so busy hitting pickets over the head that he had no time or energy to interfere with hoodlums intent on saving money.

After 3000 miles both the rear tyre and chain were worn out. The chain had several tight spots where rust stopped the links from moving, making chain adjustment very difficult. It was removed and left to soak in old engine oil after having two links removed. As the police have been cunningly trained to spot a bald tyre from a 100 yards, a new Road Runner was fitted (£30). This was down to 3mm after only five thousand miles, when the handling became twitchy at high speeds. The front Michelin had about 4mm of tread when the bike was acquired, but lasted for over 12000 miles, when the remaining tread tended to skid dangerously in the wet. The rejuvenated chain lasted for about two thousand miles, but needed adjustment every 150miles to stop it from hitting the frame on the overrun. A new chain cost twelve quid.

After 5000 miles, in a fit of paranoia, a new oil filter and 3 litres of Halfords oil were purchased. The only oil used by the engine was that lost through the rocker box gasket which had been sucked inside - Aradite was smeared over the offending joint, clearing up the oil loss except when cruising at above the ton for prolonged periods. The next oil change was 10000 miles later, rather silly given the ease with which gearbox swarf can circulate through the engine, but quite typical of the kind of abuse engines have to take these days. No other engine maintenance was planned. The four CV carbs stayed in tune, were hardly affected by the rapidly decaying silencers and still gave a reliable tick over even after 15000 miles of neglect. Valve clearances are controlled by bucket and shim, but with direct acting double overhead cams the need for regular adjustment should be minimal. Working on the dubious principle that the clearances would get bigger as the metal wore, the top end was left well alone. With electronic ignition and automatic camshaft tensioners there wasn't much else to play with, anyway.

Early one morning the bike refused to start. All systems were dead, no idiot lights and no electric start. Now, Suzuki, along with some other manufacturers, have stopped fitting kickstarts, figuring them as obsolete as starting handles on cars. This is unfortunate, because bike batteries are overpriced, unreliable and lack the durability of car batteries. While the Katana started on the most gentle caress of the button and the merest hint of choke, with a dead battery there was no way 460lbs of metal would jump into life, even given the help of some poor passer-by. Perusal of the wiring system eventually found a blown main fuse.
Those nice men at Suzuki supply a spare fuse in the fuse box, but even this didn't revive the bike. Touching the battery terminals with a screwdriver resulted in no sparks and a long walk to the local accessory store where £25 was exchanged for a battery. The new battery solved the problem, but the blown main fuse was rather confusing because, according to the wiring diagram, with the ignition turned off the battery should have been isolated and, anyway, the ignition, lights and accessories all had their own fuses. Expensive thoughts of wrecked rectifiers were quickly set aside when the bike functioned properly. Just to be on the safe side, the battery was disconnected overnight.

Fuel consumption was good, averaging 60mpg, only really suffering when riding the bike flat out at an indicated 110 mph, when it would be as bad as 45mpg. In an attempt to improve fuel consumption and help out chain life, the ridiculously small 15 tooth drive chain sprocket was thrown away, the new 17 tooth job making 90mph cruising a pleasant six grand in sixth, while still allowing the bike to take off in second gear, such was the excellent low speed torque of the engine. Indeed, the Suzuki could be trickled along at under 30mph in top, although acceleration was sluggish until 70mph was on the clock. With the new gearing the bike was averaging 65 mpg, although ton plus speeds resulted in inferior consumption at 40mpg. The new sprocket didn't help the chain very much, after five thousand miles it was worn out and required constant adjustment.

It wasn't helped by the various chain sprays which tended to end up all over the rear end of the bike, and I didn't fancy trying to boil the chain in grease, as this process has a fifty-fifty chance of depositing large quantities of hot grease over the kitchen stove, which doesn't tend to endear one to young ladies, already fed up with being transported through tropical storms. Another 3000 miles can be extracted from the chain, although the gearchange becomes quite nasty - not helped by a rear set linkage that develops slop after about 2000 miles, wrecking Suzuki's reputation for making the slickest and smoothest gearchanges in the business. When people started sticking fingers in their ears as the bike went past, it was time to fit some new silencers. As they had lasted about eight thousand miles since buying the bike and really needed replacing immediately, this was pretty good going. The four into two system is designed with the junction box for each silencer as part of the silencer. This is supposed to stop people fitting non standard exhausts but by sawing off the silencer just after the junction box there's about half an inch of exhaust pipe left for attachment of the new silencer. Unfortunately, to avoid sawing the frame or crankcases in half, the whole exhaust system has to be removed. This would have been simple enough if Suzuki hadn't decided to use the longest screws in the world to hold the exhaust clamps into the cylinder head. These screws were a very tight fit, and there wasn't enough room to wield either a spanner or socket wrench for more than half a turn. Naturally there was one screw that refused to move, eventually deciding to break off inside the exhaust clamp. Hitting the engine with a large hammer and swearing a lot were only temporary solutions to the rage let loose by this act of mechanical insubordination.

A hole was drilled in the remaining screw, and a thread tapped to take a smaller bolt. Much to everyone's surprise this worked out just fine. After sawing off the silencers, the remaining exhaust system was cleaned up with Gunk and then Solvol, the part hidden under the engine painted with heat resistant paint. The finished job looked quite good considering the state it had got into. A pair of universal silencers were purchased from a dealer on the verge of bankruptcy and desperate to sell something. This meant the price was hustled down from £38 to £30 for the pair. Although the new silencers are chrome the system looks very neat, is much quieter and hasn't upset the carbs. This must be the cheapest way of repairing wrecked exhaust systems.

Although removal of the battery leads every night had stopped the battery losing its charge, the Suzuki started blowing its fuse in a random manner at the most inconvenient moments. This was cured for about two thousand miles by the simple expedient of using a 30 Amp fuse in place of the standard 15 Amp job. Things got serious when I was overtaking a car towing a caravan going up a steep hill. Sounding the horn to show my distaste for such conveyances, the whole machine went dead just as I was cutting in front of the car to avoid the attentions of an overloaded lorry roaring down the hill. The bike had just enough momentum to make it into the driveway of a convent. The main fuse had blown, again, and kept on blowing until I disconnected the rectifier, which meant the problem was coming from either the alternator or the combined regulator/rectifier. A few miles later, the rectifier was reconnected and everything worked alright. A few days later the bike went dead again when the lights were switched on, and the fuses started blowing first thing in the morning. It was easier to carry a pocketful of fuses than strip down the alternator or replace the rectifier/ regulator unit.

After 10000 miles the rear disc pads were down to the metal and the front pads made funny noises. In view of the safety problems caused by worn pads I was astounded by the audacity of the local Suzuki dealer who demanded £36 for a set of three pairs of pads. The bike was used for another 2000 miles when braking performance had become so dangerous that three sets of pattern pads were purchased for the still hefty sum of £21. These pads were inferior in the wet and even less sensitive than the standard issue. For those who have never experienced drum brakes, please note pads last much longer and the only maintenance needed is the very occasional adjustment of the cable to take up pad wear and cable stretch.

After visiting several car accessory shops, suffering blank stares at the mention of things like rectifiers and regulators, a regulator and rectifier were eventually purchased for £3.50 each. It took several hours study of the rectifier and the bike's circuit diagram to realise than the input leads had to be soldered directly onto the diodes in the rectifier. This done, I had the heart of one new electrical system. Only an idiot would give Suzuki money for components that had already proved themselves inadequate, and only a fool would bother with breakers who refused to give any guarantee of their electrical components, and who, anyway, wanted an extortionate £35 for a component that might or might not work. I didn't even bother asking Suzuki how much money they would demand for a new one.

Because the rectifier had failed, the alternator had been affected - or maybe a burnt out coil in the alternator had wrecked the rectifier. Suzuki use a rather old fashioned electrical system where extra coils are switched into use when the lights are on. It was easy enough to wire the output from these coils permanently into the electrical system, replacing some of the power lost from the burnt out coils. Natch, running these coils with the damaged rectifier would burn out the coils eventually, but as the alternator was already burnt out this didn't seem to matter. It made riding from London to Cardiff all the more interesting, because the battery would have just enough power left, after 150 miles, to run the ignition, but if the engine stopped it wouldn't start again on the electric starter. Once, when various diversions extended the journey distance, the bike gave up three miles from home and had to be pushed the remaining distance - it was just as well that the summer wasn't hot.

The new rectifier and regulator stopped the fuses blowing, and the lights and horn could be used with impunity. The alternator couldn't produce enough power to keep the bike going without charging the battery, so after calmly explaining to various breakers that they couldn't have £45 for an alternator, it was decided to send the alternator off to be rewound. This would have been simplicity itself if Suzuki hadn't employed screws made out of the softest steel in the world to hold the alternator cover to the crankcases. They made life even more difficult by using huge clearances between these screws and the holes in the alternator coven The usual practice of hitting the outer edge of the screw head with a small chisel and large hammer resulted in the screws bending rather than turning. Tut, tut. All the screws except one were eventually removed. The last screw decided it would snap off leaving half the thread in the screw hole. This, you understand, is not a result of mechanical incompetence but of the penny pinching attitudes of Jap factories where all the screw is supposed to do is hold the case in place and not actually be reused. A drill bit the same size as the inner diameter of the thread, was carefully pointed in the direction of the snapped screw and an ancient B&D drill set on its lowest speed.

Prayers must work, because all that was left was a thin spiral of thread that unwound by hand, leaving enough thread in the casing to secure the screw. Allen bolts were used in place of the silly screws supplied as standard. The alternator was a mess of charred black insulation. The rewound job, cost thirty pounds and only took three days, including postage each way. The new system has done five thousand miles without any trouble and seems a much better bet than handing over large quantities of cash for components that are either too weak as new or too uncertain when bought second hand.

The suspension was in need of help by the end of 15000 miles (with 26 grand on the clock). The bike was still very stable at high speed, and although it didn't wallow the front end had lost some of its precision. The Suzuki had a unique combination of harsh and imprecise suspension. It did have some more feedback that Suzuki's normal attempts at chassis design, and even the engine gave the impression of being alive, of having some blood and guts, without vibrating. The bike's main problem is too much mass, and too much unsprung weight in particular. The hefty alloy wheels and disc brakes cause greater inertia forces than the poor old suspension can contain, leaving the bike ponderous through the curves, if never actually dangerous. A set of spoked alloy wheels with drum brakes off some old Italian bike, with some decent suspension from the same source would transform the beast.

After 15000 miles, two oil changes and no other regular maintenance the Katana still started first press of the button, didn't burn any oil, could reach 110 mph and average 65 mpg. It had used two chains, one battery, alternator and rectifier, wrecked two silencers and blown plenty of fuses. If the electrical problem had been sorted out quickly, the alternator could have been saved and most bikes ruin their exhausts after three years. The Katana has shown superb resistance to abuse and neglect.

Bill Fowler

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