Laverda SF750

I have to admit, before we go any further, that I am a great fan of big vertical twins. Surprising, then, that I was never entirely happy with what in many quarters is regarded as the ultimate in big twin engineering. Part of the problem probably came from the fifty thousand miles that the Laverda had collected in eleven years of loving care and attention. SF owners will have a minor fit if I mention a few of its mechanical foibles that in the final analysis leave the engine inferior in design to the XS650... but using a triplex primary chain to transmit 65hp doesn't inspire confidence - in fact, it inspires snatch at low revs, tensioner disintegration at surprisingly low mileages and an actual primary chain life of as little as 30000 miles. In using horizontally split crankcases, a crankshaft with huge ball bearings, with chain OHC drive from the centre of the crankshaft, there seems little excuse for avoiding the higher machining requirements of using gear primary drive.

Then there's that belt driven dynamo. And lets not forget a ridiculously long stroke and pistons that move in unison. The latter, of course, has always been the major problem with vertical twins. The two huge pistons have no primary balance, and the Laverda relies on massive crankcases and careful balancing of reciprocating components to limit the effects of vibes. This is an improvement on those old British twins and, with the exception of the odd electrical components, the vibration does no harm to engine or chassis. 

Up to 90mph the Laverda is the equal of the Yamaha XS650. At higher speeds the SF is both more powerful and smoother. It is not, however, free of vibration. Owners who equate the feel of the Laverda to the same kind of aliveness exhibited by the likes of a BMW or Guzzi twin have a great art for understatement. Above 5000rpm there is a certain amount of tingling through both footrests and handlebars, that is more pronounced than secondary vibes from a Honda 750 four but nowhere near as bad as a Triumph twin in full, nasty flight. With a few thousand miles use it more or less fades into the background.

The consequence of Laverda ignoring the basic engineering facts of life is that to overcome all this vibration the bike has to be overbuilt in the interests of durability and longevity. Remember, too, that Laverda had little previous experience in motorcycle manufacture, and it seems that they added a little bit more metal than was strictly necessary just to be on the safe side. This all added up to a bike that weighed over 500lbs with a gallon of fuel in the four gallon petrol tank. The major advantage of the vertical twin - light weight and agility - are almost lost amid excessive mass. Fortunately, this is an Italian bike and the effects of too much weight are subdued by high quality suspension and reasonable steering geometry, aided and abetted by decent weight distribution. For most of the time, anyway.

At low speeds the SF feels well balanced and quite easy to flick through the traffic, aided by the relatively narrow profile of the engine. The narrow tank and seat mitigate against the quite high seat height of 32 inches. The petrol tank is quite long, and combined with flat handlebars it's quite a stretch. Fortunately, the footrests are reasonably placed in relation to the handlebars, so that forearms and thighs end up parallel, to give a comfortable riding position at most speeds.

The tubular frame has no down tubes and relies on the engine to acquire sufficient strength. The steering head is well supported by the triangulation of four large diameter, thick steel tubes. The swinging arm is supported by brackets welded onto two of these tubes behind the engine and although this support looks inadequate the bike never twitches about the back wheel, so someone, somewhere must know what they are doing. The steel tube swinging arm would not look out of place on a seventies Jap bike and has the same awkward chain adjusters that make correct wheel alignment a difficult and tiresome chore. Suspension at both ends is provided by the then famous Ceriani outfit. When new this was as stiff as a week old corpse. Fifty thousand miles had helped increase compliance, but neither end could cope with small bumps in the road at low speeds. At least age hadn't left them imprecise or troubled by a lack of damping, as is often the case with year old Jap suspension.

The overall effect of frame and suspension is one of enormous security. The ride of the Laverda is very old fashioned, with more in common with sixties Nortons than eighties Jap high tech wonderbikes. Of course, with its excessive mass the SF can't hope to match the lightness and agility of old British classics, but it has the same kind of high level of feedback from the road and the same kind of feel of running on rails. Pushing the bike through a series of S bends is jolly hard work, but it is never frightening and when the road begins to run out, backing off the throttle doesn't result in any traumatic reactions .

Stability on motorways at high speeds is equally reassuring. Right up to the top speed of 120mph there are never any weaves, and the excess mass can be forgiven, temporarily, as it makes the bike immune to both side winds and the buffeting of speeding, overloaded artics which like to prey on unsuspecting motorcyclists.

It's even possible to hold onto the handlebars at the ton without incurring too much back or arm strain, although the need to glance behind because mirrors end up hopelessly blurred at such speeds means it's quite easy for the wind to catch a full face helmet, trying to snap off the rider's head in the process. In wet weather the Laverda was less than satisfactory. OK,it was a lot more secure than any number of Jap bikes that would lose their back wheel without warning and feel like they were going to lose their minimal adhesion to the tarmac at any moment. But then the SF is a very expensive device and is supposed to be a classic. Running on fairly new Avon Super Venoms there were occasions when the combination of a high centre of gravity and excessive weight would let the back wheel move off line when cornering. There was usually some warning of this activity, but it was often difficult to control because of transmission slop due to the nasty primary drive and a stiff throttle.

A Yamaha XS650 owner would find the Laverda's handling marvellous; a Bonneville or Norton owner would wonder what all the fuss was about; and the owner of a modern Jap four would need a course in muscle building and a bit of psychiatric treatment if he decided to swap bikes.

The original SF had a nicely cast TLS front brake, back in '71. These bikes are very rare, the later SF is a little more common and has twin discs that are powerful, a little lacking in feel, but actually work quite well in the wet. The poor old SF3 was a master of overkill, with a totally silly disc rear brake in place of the better suited SLS drum used by the other models. If the bike is used to the limits of its performance then the twin front discs are definitely needed, although the TLS brake is probably one of the best in the world with a remarkable degree of control - but it is prone to fade when trying to retard 500lbs from 120 mph.

The clutch is heavy but precise, the gearchange was still slick and there was never any hint of missed changes, although it was usually impossible to find neutral from a standstill. Trying to rush changes was not on, but the gearbox didn't seem to object to clutchless changes. Excessive riding in town could cause a little clutch drag, when it was necessary to adjust the clutch at the handlebar lever to gain increased leverage. The riding position and heavy clutch meant that town commuting quickly tired the left hand, but the motor could rumble along in third or fourth at quite low speeds only spoilt by transmission slop. The SF never felt at all relaxed under such circumstances, never settling down into a happy growl until at least 70mph was on the clock.

Fuel consumption was never anything to inspiire the mean or desperately poor. Averaging 45mpg, it would only return 50mpg under the most modest use of the power. Cruising at the ton reduced it to 40mpg, while really thrashing the engine with the rev counter courting mechanical disaster at eight grand used up the gas at 30mpg.

Twin carbs with a surprisingly small bore of 30mm were of a relatively primitive design lacking the sophistication of CV units fitted to the more economical of the Jap twins. Again, excessive mass and silly primary chains can't help the SF to achieve reasonable economy. The cooking version of the engine, in GT750 form, had smaller valves, less radical cams and a lot less power, managing to average a somewhat more reasonable 55mpg.

Riding the SF for a few days through the usual rain and cold would quickly turn chrome and alloy into an horrible mess. The Laverda needs to be cleaned and polished after every ride to keep it in good condition. Paint on the tank and side panel didn't tend to peel off but looked like it had been applied by an apprentice whose skills had been subverted by the fumes given off by paint thinners. The paint on the frame was an altogether different can of worms and usually went AWOL after a mere years exposure to UK weather.

And then there were the handlebar switches that lacked feel when new and couldn't take the wet weather - owners of twenty year old Hondas would be shocked by the lack of quality... long term owners will have dumped the switches, resprayed the cycle parts and taken out shares in Solvol, so these aren't really relevant complaints. But, oh dear, that quaint Bosch dynamo and associated regulator would make a Morris Minor owner go all misty eyed. Electrical integrity is especially important because Laverda were ahead of even the Japs in dumping the kickstart and this kid, for one, would not even dream of trying to bump start 500lbs of top heavy Italian exotica. Some dynamos are in trouble by 20000 miles, so prospective purchasers should ride everywhere with full beam switched on to check out that some kind of power is actually being generated. On very cold mornings it's often necessary to jump lead to a car battery to get the starter enough power to overcome the drag of the cold oil.

The crankshaft is very tough, the carefully selected pistons and high quality bore job means rebores can take as long as 75000 miles before they are needed, the valvegear is surprisingly resistant to bounce (given the size of the valves) and even the camchain and tensioner can make it past fifty grand without needing replacement . At least the small end plain bearings and roller big ends are relatively easy to replace and don't mean a new crank is needed as is so often the case with Jap bikes. The engine has obviously been built out of high grade materials with long life and ease of maintenance firmly in mind. Rear tyres are down to 2mm in as little as 7000 miles, while the front can go for as much as ten grand.

Riding on worn tyres doesn't cause too many problems in the dry but definitely aint recommended in wet weather. Chains last anywhere between five and ten grand, depending on maintenance and power usage. Disc pads last for six to eight grand and the rear drum shoes can make it all the way to twenty grand.

The modern Jap multis make the SF seem very, well, old. In an era when Jap bikes handled so badly the SF was a welcome relief, but the basic flaw in its design of excessive mass now make it little more than a curiosity piece. Yeah sure, it looks so right, so brutal and effective, that it's easy to be taken in and write pages of creepy prose to the effect of what a wonderful piece of classic machinery it represents. But its engine doesn't last any longer than an XS650 and its performance is no better than a good 550. If we were talking reasonable money, say £300 to £500, then the SF might have a lot going for it. At present prices leave it to the Sunday afternoon brigade who know no better...

Loose Lines [Issue 3]

The air conditioner sounded like it was on amphetamines. It didn't do much for the midday heat. Staggering from my bed in the fourth floor flat, I only fully realised where I was when I saw the crazy traffic out on what the Thais optimistically call roads.

It was then the shakes started. Visions of my previous days attempts at actually riding a motorcycle in Bangkok had all the clarity and terror of my failed attempts at indifference to the fist sized cockroaches that insist on scuttling across the walls of this room. Snippets from the insanity bureau. 

Trying to wipe the grin off my face, I figured how much better off I'd have been staying in deep freeze Britain, rather than becoming financially crippled by my involvement with a publishing project so strange and delinquent that I refuse to go into any further details. You understand, I'm in Bangkok strictly on business. It was only the realisation that Loose Lines was two blank pages that pushed me into the dubious act of hiring a motorcycle for the day.

Those who have never had the pleasure of visiting the City of Angels will be unaware of joys in store for them. Thai drivers make London cab psychopaths seem mild. The road surface defeats even the most softly sprung trail bike. All road regulations have been cancelled (if there were any in force in the first place). The horn is the most popular form of traffic control.

New motorcycles are very expensive, most people ride around on small two strokes that can trace their birth back a couple of decades. Who said old Jap iron doesn't last? Engines are often housed in cut down frames with a mixture of cycle parts from whatever happens to be available. When a replacement part is needed it is often produced in one of the many Thai workshops that litter the centre of the town. With average wages running at fifteen quid a week.and a naturally skilful people, these workshops can knock up anything from a silencer to a piston at prices that make heavily taxed imports obsolete. The largest bike I saw was a Yamaha XS650 - a bike completely unfitted to take on the madness of Thai traffic. There was also a sixties Honda CB450, the appearance of which I found reassuring as I owned one for three years. Every little piece of recognisable reality helps in a town where the craziness is sincere.

My first encounter with the traffic came as a mere pedestrian. Trying to cross a junction that made central London seem like a village square, I had to admire the skill with which vehicles actually managed to avoid hitting each other. Families on small motorcycles, overloaded buses, hurtling cattle trucks, speeding taxis, old Jap cars low on their springs, three wheel taxis that looked like they had escaped from a golf course, and just about everything else you'd care to name.

The noise, smell, dust and speed were intoxicating stuff. The only way to cross the road is to actually just walk into the traffic, hoping that the cars will slow down enough to make it safely to the other side of the road. Much to my surprise, this works, although the more psychotic try to blast you away with their horns.

Hiring a bike in Bangkok is fraught with danger. The usual con is to demand a huge deposit for a bike that conveniently falls apart after the first few miles. There's no insurance and few people bother with silly things like crash helmets. Buying anything in Bangkok involves s strenuous round of bargaining. The first offer was $50, but pointing out that I was not a rich American tourist or financially imprudent Australian reduced it to forty. I offered ten. That got me one of those wide but dubious Thai grins. I would have been quite happy to walk away if I couldn't get a good deal, the more I contemplated riding a motorcycle, the more I realised how much I disliked suicide. He eventually came down to twenty, while I offered fifteen. Walking away for a few yards saved me that final five dollars.

The bike had a Suzuki engine that looked like it night once have been housed in a mid seventies TS250. It was now in a homemade frame that reduced the seat height to about 25 inches. It started first kick, huge clouds of blue smoke and an engine that rattled like an out of control NSU Quickly. I'd only offered my passport as a guarantee that I'd bring the bike back at the end of the day, as I'd assumed I had one of the better bikes. Jumping an the seat revealed that the suspension was as taut as a fifty year old hooker . The front brake lever was mostly free play. Adjusting the TLS helped, but the cams looked like they could lock up the brake. I hoped the owner wasn't figuring to sell my passport after the bike had delivered a terminal blow to my life.

Dropping the clutch revealed that the engine had little power at low revs. Whacking open the throttle produced a neat wheelie down the relatively quiet sidestreet. As soon as the front wheel touched the ground, the bike wanted to veer off to the left. Backing off the throttle started to stall the engine. The only way to travel slowly was to scream along in first or second gear.

Great, I thought, the handling abilities of a Tiger Cub and the power band of a Kawasaki 500 triple. Applying both brakes at the approach of a main road didn't help reduce much speed; backing off the throttle and slamming into first gear cut the speed enough to lean the bike into a sudden gap in the traffic. Then things got really bad.

There were four lanes of traffic trying to criss cross each other in a mad melange. The heat was already burning a hole on the back.of my neck. The engine refused to run at all unless it was strung out on full throttle. A bus full of school kids thundered past and turned across my front wheel. The kids waved. I struggled with gears, brakes and handlebars, flicked the bike inside the bus. The engine spluttered, whacking open the throttle, heading for a hole in the traffic with front wheel a foot off the ground. I flicked up through the box, gaining speed, aiming the bike where there were gaps, and getting a head full of abusive horns when I forced holes in the traffic. The bike was devoid of any instruments so I had no idea how fast it was skimming the hot tarmac. Working on the principle that I had to keep ahead of the traffic to minimise the chances of attack from behind, for a short time I was in with the mindless momentum of the traffic.

Then the front wheel hit a huge pothole. The old forks didn't have a chance. I was kicked high off the seat and figured my spine had been cut in half, at the very least. The bike leapt in front of a lorry which swerved out of the way. I was in the middle of a road that went on for miles, there was no way I could stop and I didn't have any health insurance . The throttle was against the stop, the brakes couldn't be relied upon, the heat, grit and fear were making it difficult to focus and I was surrounded by manic grins out for revenge...

Bill Fowler

BSA 250 single: When the going gets tough, the tough get vague

Having carefully arranged the running of this magazine so that someone else risked their life and timetables to bring you the word on British bikes, you can imagine my horror when that person disappeared off the face of the earth aboard my personal vehicle, leaving some wreck of a BSA 250 single in its place. I wouldn't have minded if it had been a Vincent V-twin, or even a Norton 650 or even a BSA A10 or even a BSA Bantam, but these single cylinder BSA 250s are tough, vicious, nasty, crazy, violent devices that can break a persons ankle as soon as look at them.

Not that I'm totally unaware of the joys of British bikes, you understand, the plain fact is that every relationship I've had with one of the blighters has turned very sour after the first few hundred miles. I have as much empathy with British bikes as I do with fat women, which as anyone who knows me will tell you is zero.

I approached the bike with care and caution. I'd thrown away my tennis shoes, replacing them with a pair of very heavy motorcycle boots that some idiot in another motorcycle mag had caused me to buy one size too large in order to fit in an extra pair of socks, and which were in consequence impossible to walk in. Despite the cold, I was wearing only a t-shirt and a pair of lightweight jeans. I figured the bike would refuse to start if I had the audacity to approach it fully clothed in the expectation that it would actually fire first or second kick. This proved a wise move as the bike made no sign of coming to life despite tickling the carb, playing around with the awful switchgear and getting the engine past compression before leaping with all my ten stone onto the kickstart. After the tenth kick I concluded that Malone had sabotaged the machine in deliberate retribution for my failure to pay him any money.

Further thought revealed the idea that the chap's brain might be suffering from the days when he used to run a bordello, he might actually have been under the illusion that the heap of junk was a valuable classic that needed protection from thieves. Getting back to basics, I checked the petrol which was OK. There were, however, no sparks which ever switch position I tried. I eventually found a switch hidden under the side panel. Sparks! On the fifteenth kick the thing actually came to life. I revved the engine until the motor started bouncing in the frame. That'll teach you, I thought. Of course, there was no way the bike would do anything as civilised as tick over. As soon as I let go of the throttle it went dead. By the time I was dressed to take on the rigours of our wonderful winter, the engine had gone cold. It took another fifteen kicks to get it going again. 

Remembering to hit the gear lever on the wrong side of the engine, I was away.  For the first few hundred yards everything was great, if only because I was savouring the breeze dissipating the heat and anger that had just built up. We were doing 20mph, the engine sounded like a pneumatic drill trying to break into a box of ball bearings and the grips were were trying to leap out of my hands. I changed up to second, or rather after about six attempts I finally got past neutral and made it into second. The clutch lever had torn my hand muscles in half, and the gear lever had cut through several millimetres of top quality leather to try to crush my foot. I tried for third without the clutch lever and this made some very encouraging graunching noises,the bike felt like it leapt a foot off the ground when the power finally connected. With forty on the clock (well, actually, with the needle gyrating between thirty and fifty) the only thing I could find to commend 'was the reasonable directional stability. Anyone who's complained about secondary vibes from some Jap multi ought to try five minutes aboard some ancient British wreck to find out the real meaning of that word.

Aware that the British bikes were a little, er, lacking in decent brakes and that some devious person might have removed the brake pads as an act of ultimate revenge, I'd kicked the gear lever down through the box and backed off the throttle well before the junction. This proved a very wise move as the brakes were just as bad as expected . They might just be more powerful than those fitted to a Raleigh Runabout, but I wouldn't place my life savings on it, although thinking about the sum involved it wouldn't make much difference if I did.

Stopping at the junction coincided with the bike running out of petrol. KILL. Unfortunately, I'd left the hammer at home; foolishly, I'd left the tool kit there too. I pushed the bike to a petrol station and filled it up. The first mechanical problem reared its head after I'd handed over several notes for the petrol. Yes, the petrol tap started leaking. I just shrugged my shoulders, full of visions of presenting a charred heap to Malone. In fact, I cursed because I didn't smoke, so didn't have a match handy I could throw at the thing. It started after fourteen kicks this time.

My next problem was trying to use the bike to climb up a steep hill. In third the bike was bogged down and threatening to stall. In second it was screaming along threatening to explode. Natch, I kept it in second. We didn't seem to be going very fast so I enjoyed the scenery and the free massage. The bike seemed to give a sigh of relief when it made the crest of the hill. I let it lounge in fourth for the descent. I'm not too sure what the machine actually consists of. I think there's a B25 engine and chassis in there somewhere. The other bits and pieces seem to have been collected off the local scrap heap and attached with whatever fell to hand. The seat, for instance, doesn't feel very firmly secured to the frame rails and the stuffing has been accidentally deleted. This means that all the vibes from the OHV engine pass straight through to the rider. Not my idea of fun at all.

When new the engine is less than perfect. With quick wear valvegear, pistons and primary chain it only takes a few thousand miles for the engine to start developing problems, for the vibration to increase to frightening levels and for what little performance is normally available to evaporate. Throw in one of the weakest gearboxes in the business to make life really interesting. And that's on a good day. This particular example looked like and felt like it had last seen a good day about two decades ago.

Glancing behind to make sure it was safe to turn right, I found my vision obscured by clouds of blue smoke. Amid the normal engine noise I thought I could hear a ticking noise, that increased in frequency as I blipped the throttle to make sure the engine didn't die while I waited to make the turn. With any luck the valves would knock a hole in the piston and I could go and do the decent thing by buying a bus pass. Unfortunately, the noise and fumes cleared as suddenly as they appeared. I can't say that the vibes and noise had faded into the background, but by riding along at low speeds on the minimum of throttle in fourth gear they were kept down to a tolerable level, although cruising along at a maximum speed of 35mph was not even my idea of fun. In cold weather I want to make the journey in the shortest possible time and anything that slows me gets me exceedingly angry.

Much to my surprise I arrived at my destination without further incident. The bike had even decided to idle, and the fuel seemed to stop leaking once the engine was running. On my return journey I decided to rev the engine flat out in fourth to see what it would do. Acceleration was about on par with a Honda C90, although I couldn't fall asleep because of the vibes and the need to keep an eye open for stray pedestrians and dogs - the brakes were definitely inferior to the C90. Between thirty and fifty there was a quite remarkable degree of vibration considering the small amount of power the engine managed to produce, but once past fifty the device actually smoothed out a little and the speedo stopped gyrating quite so wildly. The only way to slow down was to use the engine braking and rush down the gearbox, the brakes made hardly any difference.

I wasn't beginning to like the bike, but it was rather more stable than many other hacks, especially some of the old Jap iron whose suspension had been laughable when new, let alone with a decade's wear and abuse. The thing could be flicked around greasy roundabouts with no problems, and even rode over the neglected surfaces of inner city roads without trying to flip the rider off the bike. Of course, the suspension didn't actually absorb very many of the bumps, that would have been too much to hope for. I later discovered that there was loads of a free play in the swinging arm bearings, so its stability was all the more remarkable.

Forced to ride the bike for a whole week, I was able to ascertain that the fuel economy was really rather good. Despite the brutal revving of the engine, the attempts to wreck the gearbox and the leaking fuel tap, it was returning 120mpg. At first, I refused to believe the mileage on the ancient speedo, but it appeared to correspond with distances travelled over known routes, so I had to accept that a twenty year old design in a near wrecked state was bettering many modern Jap 250 singles. These modern bikes were far faster and far more civilised, so the BSA couldn't really claim too much fame for such economy.

I even managed to get the engine to fire after a mere nine kicks from cold and just six kicks when warm, although on one nasty occasion the bastard kicked back hard enough to break my foot, except that I was saved by the stout boots I insisted on wearing whenever I was within a few yards of the bike. They were also useful for kicking it, when the bike misbehaved. You have to show these old British singles who's in charge.

In some ways it was useful to have so many intrusive mechanical problems because it took my mind off the cold and wet weather. It was all too easy to spend the journey on some smooth Jap multi screaming at God for inflicting such awful conditions on the UK. The BSA always demanded maximum effort and attention to get the gearchange right , to keep the engine out of the really bad vibration periods and to slow down well in advance . I took the bike on the motorway once. It didn't like being screwed along flat out for several miles. I knew it didn't like such treatment because it responded by gradually slowing down until it was doing no more than forty and the clouds of blue fumes had returned. Natch, it started to rain. But the bike never actually failed once it was running. Once it had time to rest, the performance returned to its normal levels.

The funniest moment occurred when I was returning to the bike after doing some shopping in the town centre . Some young chap was peering closely at the bike. I was about to walk away on the assumption that he might have been the original owner off whom Malone had borrowed the bike, when he saw me before I had a chance to disappear. The poor chap wanted to buy the thing. I checked his forehead to see if there was evidence of a frontal lobotomy. He offered two hundred quid, then three. Laugh? I almost went and brought Classic Bike... 

Bill Fowler

Suzuki GT500

The Suzuki engine is smooth and remote enough to let the bike cruise at deceptive speeds. The straightforward two stroke design knocks out 44hp from 493cc. The short stroke vertical twin has little by way of a power band, happy at 50 or 90mph in top gear. Acceleration is never the arm breaking Kawasaki 500 triple type of fun and games. As with so many Suzuki two strokes, the GT500 is more sophisticated and easy going than rival four strokes. Only when flicking through the five speed box and revving the engine through the redline does the GT show any allegiance to the bad old times of two stroke technology. And even then, it avoids the usual clouds of blue exhaust smoke.

The engine is well supplied with needle and roller hearings to combat the effects of poor lubrication which is the bane of two stroke technology. The separate oil supply, gear driven oil pump controlled by throttle movement, and direct oil injection combine to supply oil to parts many other two stroke designs fail to reach. The flow through the oil pump can be adjusted to reduce the loss of excess oil through the exhausts. The four bearing crankshaft lasts up to 60000 miles before needing a rebuild. Needle roller small ends have been known to break up on really thrashed engines at quite low mileages. Terminal mechanical failure occurs when the oil pump gears strip their teeth. But both of these events are rare. Bolts retaining the cylinder head can strip their threads, while engine bolts can snap off if they are not regularly checked for tightness.

The gearbox is one of those short movement devices, needing the minimum of foot pressure. As the internals age, selection becomes less precise. Once past fifty grand, the lack of feel in the box means missed changes are all too common . Remembering to change the gearbox oil every few thousand miles minimises the effects of ageing. Transmission snatch is minimal, aided by gear primary drive and cush drive in the rear sprocket.

The multi-plate clutch combines the usual Jap properties of light lever pressure with no tendency to slip when abused. It even avoids clutch drag from cold or under pressure from heavy traffic. Gears have been known to strip their teeth (especially first) but this can be blamed on lack of regular oil changes. 

The engine is housed in a duplex frame that can trace its history all the way back to 1967. Geometry changes and extra bracing marked the evolution of the original T500 to the GT500. The weakest component of the chassis is the swinging arm, lengthened to increase the wheelbase of the GT to 57 inches, but not designed to withstand the resultant increase in torque when the going gets rough. The frame is constructed from suspiciously thin tubing, that judging by the frame's weight is made from mild steel.

Suspension is quite stiff when new. With a few years wear it loses a lot of this tautness. Never well damped, both front and rear benefit from replacement. The cost conscious can obtain relief by using stronger oil in the forks and replacing the rear with a pair of cheapo Girlings. Nevertheless, even on worn suspension, the Suzuki does not develop any of the nastiness inherent in the rival Kawasaki stroker.

The combination of long wheelbase and 400lbs make the Suzuki stable in a straight line, but reluctant to flick through the curves. The ride is typically remote (for an early seventies Suzuki), the rider has to take time to find the bike's limit, hindered by this lack of feedback. On new or modified suspension all the GT needs is some extra muscle to overcome the top heavy feeling. On worn suspension, it's easy to catch the back wheel out, when the weak swinging arm adds to the hinged in the middle feeling. At such times, backing off the throttle or using the front brake can make the whole bike twitch. Throw in some bumpy roads and adverse cambers and the GT can be in real trouble, needing both lanes of the highway to survive.

Fast motorway work is no problem. The bike can cruise at up to 90mph. Passing through the wake of some articulated lorries or fighting against a steep incline requires a change down to fourth gear. Stability in cross winds is good. Combine worn tyres, aged suspension and a poor surface to induce a high speed weave. It never gets out of hand and is removed by fitting an aluminium swinging arm and a decent set of shocks. The imprecise front forks allow the bike to wander at high speeds, which keeps the rider from falling asleep. Racing with GTI owners is difficult, because the GT doesn't easily produce its last dregs of power to spin the speedo past 100mph. Sitting upright doesn't produce more than a true 95mph. A long road and crouched rider eventually attains a 105mph top speed.

The Suzuki's real failing, and one that can't be easily corrected, is in wet weather riding. Again, the awful remoteness of the tyres means there's no way a sliding tyre can be recognised until it's too late. A decent set of British tyres that gradually lose their grip over slippery patches is the best antidote. At least the geometry and weight distribution means the Suzuki comes back in line. There are far more dangerous bikes than the GT on the road. Wet weather riding drastically cuts the speed of the bike, although the lack of a vicious powerband limits the cheap thrills of wild slides. 

Once used to the Suzuki's handling limits quite rapid bend swinging is possible. It would be lost against some of the very modern iron, but can take on rival four strokes from the same era and with decent suspension can stay with its main rival, the Yamaha RD400. It's far safer that the Kawa 500 triple (but, then, what isn't?). Most British twins, with similar performance, will see off the GT down country lanes. But the Suzuki will catch up on the straights or after the British bike breaks down. 

The real improvement occurs when the GT's chassis is replaced by a Dresda frame kit. Based on an improved version of the Norton Featherbed frame, these kits cut weight by a hundred pounds, while endowing the bike with stable and agile handling that makes even the modern stuff look silly. The lower mass allows gearing for 115mph without affecting acceleration. The Dresda forks and 8LS drum front brake are top quality stuff. One of these devices is worth tracking down.

The single front disc fitted to the GT is very silly. Having no more power than the TLS fitted to the T500, it doesn't work at all well in the wet - nothing happens for the first few moments then the wheel locks up. Pads last for around 7500 miles, and the caliper needs to be stripped down when pads are changed to stop it from making strange noises and/or seizing. It requires minimal finger pressure to operate , but in the dry it's difficult to control because it lacks any useful feedback. SLS rear drum brake is sensitive and doesn't lock the wheel. The rear wheel copies old British technology by being quickly detachable - remove the wheel spindle and spacers, letting the wheel come away while leaving the chain and sprocket in position. It's a pity no-one else bothers with such niceties these days. 

A rear Roadrunner goes for at least ten thousand miles while the front can make it to fifteen grand. Those who like to live dangerously will find that a worn front tyre can step out in a suitably suicidal manner, while a slick like rear will induce some nice weaves at speeds above 60mph. Worn tyres with no feedback are not a good combination. The long swinging arm and small engine sprocket extract their price on chain wear, which can be as little as 5000 miles, although modest riding and regular maintenance can double its life. Worn chains are very prone to snapping - they don't usually break into the crankcases, just make a mess of the chain cover. Swinging arm bearings are prone to rapid wear, often in need of replacement by as little as ten thousand miles. Bikes involved in crashes bend the down tubes of the frame with absurd ease, if the engine looks out of line with the horizontal plane, then the bike's been in an accident.

Stock silencers can last for up to five years. They tend to rust on the outside first because of the oil coating they receive from the exhaust fumes. A large array of expansion chambers are available that increase noise and decrease performance. It's also possible to tune the engine, enlarging the ports, increasing compression and dumping the air filters. This tends to destroy the nice nature of the engine and reduce reliability. It's far better to go for a stock engine.

The style of the GT is wrecked by a slab sided tank and poorly integrated side panels. Available in a bland shade of blue, the Suzuki signed its own death warrant when it was introduced in 1975. There are many bits and pieces that can be bolted onto the Suzuki to improve its appearance, especially a nice line in alloy petrol tanks.

The earlier version of the GT, the T500, looks far better because it has a classically rounded tank that highlights the robust lines of the engine. The T500 was also faster, with 50hp and 110mph. Combining wilder acceleration with a poorly braced frame and soft suspension makes for interesting road manners. The bike was helped by a little more feedback but it was easy to lose the back end on bumpy curves. Suspension and frame were improved in '72 , but even then they are inferior to the GT. The more powerful motor had a shorter life, needing a new crank and rebore by 50000 miles. The engine had some of the blood and guts feel of the Kawasaki 500, but it was never as dangerously wild as the triple. Acceleration to 60mph of under five seconds will still surprise many modern bikes.

The T500 averaged 45mpg, while the later 500 managed 50mpg. For sure, thrashing the GT at maximum revs would increase that to 35mpg, but more moderate 90mph cruising returned better than 40mpg. Pottering around on the minimum of revs but staying up with out of town speed limits can return as much as 60mpg. With just over three and a half gallons the GT had an effective range of 150miles before needing reserve.

Riding position suffered from the usual forward mounted footrests that didn't match even the raised handlebars. The GT could be cruised for about an hour before the poor stance inflicted on the rider meant a sore backside and strained arms. The seat was firm, slippery and retained water. Not a good combination. Flat handlebars and rearsets help redistribute extra weight over the front wheel, aiding stability.

Starting is only difficult because the kickstart is on the left hand side. The force needed is minimal and the motor comes to life on first or second kick. Those ignorant enough to pump the throttle before the motor has fired will oil up the spark plugs, because this operation increases the amount of oil flowing through the engine. Stalled engines can be started by pulling in the clutch and kickstarting, without the need to waste precious moments finding neutral.

Lights are entirely inadequate, quartz halogen units are recommended as the engine doesn't produce sufficient vibes to affect them. Unlike some of their four strokes, the alternator and rectifier are both made well enough to avoid burning out. Handlebars switches are water resistant, but the light switch is a trifle awkward to operate when wearing thick gloves.

The GT 500 is very practical motorcycle that can provide plenty of cheap fun. Even with ten years of wear and abuse there are still many bikes on the road with plenty of engine life. This is quite remarkable for a two stroke design. The likes of Yamaha RD400s and Kawasaki KH500s are on the scrapheap in much less than half the 60000 mile engine life of the GT. There are plenty of cheap spares and tuning goodies. The engine is simple to strip down and easy to maintain. Ignition timing can be done without a strobe. Even if it's not spot on, the engine avoids burning holes in the pistons or seizing.

The ride quality and handling abilities are a little dubious. Most of this can be sorted by fitting decent suspension and a stronger swinging arm. Many used bikes will already be modified. Try to avoid those that have heavily modified engines. The GT tends to attract rather more sedate riders than the T500, which increases the chances of picking up a good bargain. Nice examples of the T500 are now very rare. The GT500 probably won't make it as a modern classic because it doesn't have the looks. So the bike's far from perfect,but prices start at £200.

Moto Guzzi Le Mans 850 Mk. 3

The gearchange has all the precision of a sawn-off shotgun, the shaft drive tries to whip the back wheel off line when the power is turned off in bumpy corners and all the controls are heavy enough to send the muscle building industries right out of business. Oh, and acceleration up to 70mph was about on par with a good Jap four hundred twin. But these are minor quibbles when compared with what the Guzzi can offer out on fast country roads when all the elements of the bike's design begin to make some sense.

Guzzi claim some 78hp for the Mk3, but this can be taken with a pinch of salt as the bike goes no faster than the earlier Mk1 which claimed a mere 70hp. The layout of the engine should be well enough known for me to avoid boring you to death with paragraphs of mindless technical prose. Suffice to say, it's a V-twin with pushrod operated valves and a five speed gearbox. It's been around for well over ten years, so most of the problems should have been well sorted. The Mk3 has specially coated bores which mean that it can't be rebored, although the process is supposed to let the pistons and bore last rather longer than conventional cylinders . The older bikes were often in need of a rebore by 50000 miles, the largest distance covered by a Mk3 that I could find was 42000 miles and there didn't seem to be any significant signs of bore wear, so the Mk3 might well manage to run for quite large mileages.

Although the bike can potter along at 35mph in top gear, any attempt to accelerate will send tremors of rebellion throughout the length of the machine. It really needs to drop a couple of gears at low speeds to get the power turned on without the engine trying to separate itself from the frame. Torque reaction, I believe it's called. With the cylinders spaced at 90°, primary and secondary vibes effectively cancel themselves out, leaving the con-rods and pistons, which are slightly out of line with the opposing set, to try to twist the crankshaft. The effects of this depend on engine revs, but only really manifest themselves at certain revs, as the frame and engine can be designed to absorb the vibes for most of the time. Whatever nastiness the engine produces it's way ahead of vertical twins, less intrusive than some secondary vibes from Jap fours, and a little bit more pleasant than certain Kraut flat twins. The Guzzi is most relaxed between 80 and 115mph, a speed when, anyway, most of the interesting power is produced.

Riding in town does not really suit the chassis. The front forks get some help from air suspension, making them a little more compliant than on the older bikes, but the Guzzi still relies on stiff, short movement suspension to obtain that secure, sure footed feel at high speeds. Thus town riding has to be sacrificed for high speed fun and games. Gunning the engine in first or second is about the only way to get it to shift at low speeds, but the engine never feels very happy given such lack of sympathetic treatment. A heavy throttle and clutch don't help things in town, either. Just using the brake pedal to operate the linked brakes is the only easy option available. And the system seems well enough designed to cope with all kinds of road surfaces.

At low speeds the chassis takes a bit of effort to fling 460lbs around, but with the exception of backing off the power, it's really quite stable and there's always plenty of feedback to make sure the tyres never let loose without warning. The bike is long and low, the faster it goes the more stable it feels. Above 70mph, the suspension begins to work properly, actually absorbing some of the bumps in the road. The Japs can design suspension that is good at both low and high speeds, but the Italians are still building forks and shocks that don't wear too rapidly, so that with equally aged bikes the Italian stuff is going to come into its own and the Jap stuff become increasingly imprecise.

Precise steering is something that the Guzzi always seems to retain, regardless of how old or how thrashed the bike has become. The bike is rock steady at the ton, quite easy to throw through fast bends and has that delicious feeling of security that only the better Wop and British bikes seem able to achieve.

The Guzzi uses a tubular frame that has excellent support for the steering head and swinging arm pivot. The bottom frame rails are detachable to allow the engine to be removed; a system of which I can hardly approve - if the detachable rails aren't really needed why bother fitting them, and if they are wanted then they need to be more securely attached than via a couple of bolts. The large chunk of alloy engine housing must contribute quite a lot to the strength of the frame. 

The chassis is really only upset by worn tyres ,which when down to 2mm, let the bike develop a slight weave above the ton, which can turn quite nasty flat out at 130mph. On illegal tyres the Le Mans can turn in some quite amusing speed wobbles. Fortunately, merely backing off the throttle lets the bike regain its composure.

Wet weather riding could also turn a little frightening if the engine speed was mismatched with road speed when changing down. This would either stall the back wheel or have it spinning out of control . Under such ill treatment the back end a will try to lurch around 3 and catch up with the front wheel . This problem is rather more pronounced than on, say, a BMW, and can get rather violent if the engine is just coming on cam at that particular moment. This is all rather a pity because otherwise the Guzzi is eminently stable and safe in wet weather. If the bike wasn't quite so unhappy at low revs in high gears it could have been run along in fourth or fifth for most of the time , but this easy option was denied and there was no way I could relax on the Guzzi in wet weather.

At such moments it might have been helpful to be able to operate the rear brake on its own, so that such machinations could be kept under control. This marginal loss of control was more than made up for by a braking system that was sensitive enough to avoid locking up the wheel in wet weather, yet didn't suffer any of the wet weather delay of many rival systems . Once I managed to restrain my right hand, I relied solely on the brakes, as they provided all the stopping power I ever needed and the extra freedom afforded my right hand was most welcome.

The handlebar fairing was better than nothing in wet weather, but was hardly up to the protection afforded by the BMW RS fairing. It was possible to get a little more protection by ducking down behind the screen, but it wasn't really enough to justify the assault on the old bike's appearance. The Mk1 had a raw and brutal look that was lacking in the squared off appearance of the Mk3.

Even on a bike that was only three years old, with only just over ten grand on the clock, the paintwork on the frame was beginning to rust away and some of the chrome was starting to flake off. The finish was better than earlier efforts. When paint would peel off the tank and the exhausts would turn bright red after only a year. It's still not exactly inspiring stuff.

The gearchange and clutch action.are marginally improved over earlier efforts but they don't represent the same kind of progress found in gear swapping as evidenced by BMW twins over the past decade. When new, the action is just about acceptable but with ten grand on the clockthe box needs very precise coordination to attain a clear change, any fumbling becoming immediately apparent through the very direct shaft drive. This isn't anything to really worry over, as a bit of riding soon masters the technique and the problem fades into the background. Problems with switchgear don't disappear so easily. It's not that they can't be operated easily, more that on occasions operating the switches fails to produce any results. Indicators that blip at varying rates are merely amusing, but headlamps that fail to light up when expected are a little more disturbing. The switches themselves are quite well placed and quite positive - it's just a pity they only operate sporadically.

Problems with the Guzzi engine usually arise due to neglect of maintenance. Earlier bikes used to like to wreck their shaft drive oil seals at amusingly low mileages - and even a couple of Mk3s managed to keep up this quaint tradition at around 20000 miles. Valvegear can be a problem at thirty grand with worn out tappets and burnt exhaust valves the main areas of concern. The crankshaft is pretty tough, but the dry diaphragm clutch can also give up the game at thirty grand if the bike's been abused. The gearbox doesn't fail, it just gets less and less precise as time goes by. The most that could be expected of the older bikes was 75000 miles, but they were often in the casualty ward by half that distance. It's a bit too early to give any definitive data for the Mk3 but it certainly seems no worse than earlier bikes The whole of the electrical system from the generator up has to be viewed cautiously.

Fuel economy wasn't up to the standards of the earlier bikes. Under mild use they could return up to 70mpg, but the Mk3 wasn't able to better 50mng and could often do worse than 40mpg. Expect around 45mpg average.

Rear tyre wear was not inspiring either. Around five grand seems to be the average. Blame the high mass and direct shaft drive. The front tyre could go for a little under ten grand. Brake pad wear was also frightening with five grand the most that can be expected . Some money can be saved on servicing, as everything is nicely straightforward. The only tedious business is keeping the carbs in balance as they are often out in just 500 miles - this increases vibes, fuel economy and the engine's dislike of low revs.

OK then, the Guzzi can't suffer the same kind of neglect as some of the Jap stuff, but it's equipped with a nice line in the chassis department, feels wonderfully relaxed as a 90mph cruiser and even in its Mk3 form looks quite flash. And, with a bit of loving care and attention, the engine will last for reasonably long mileages. Personally, I wouldn't spend the fifteen hundred quid necessary to get hold of a decent example, but then I'm not convinced that such large sums are needed to enjoy my motorcycling. You could do a lot worse.

Kawasaki Z400

Kawasaki were, of course, very well aware of the fact that two pistons moving in unison were going to create plenty of primary vibes due the inherent lack of balance. That's why they added a chain driven balance shaft to counteract these vibrations. While such a balance shaft can cancel out the forces of pistons at certain points in the combustion cycle, the shaft, itself, does nothing to balance it other points in the cycle. Thus the elimination of vibration is impossible in such a situation. Throw in some wear to the extra components such a system employs and there's more vibration than if the poor old engine was left as just a plain and simple design. If the Kawa doesn't vibrate much as a Triumph 350 or 500 twin it is because it has a better engineered engine, with a proper four bearing crankshaft and an OHC design less affected by whatever nastiness the engine produces. The Z400 has vibration levels little better than the XS650, which can be considered the ultimate in straightforward design.

The simple solution to the vibes is to have the pistons moving up and down alternatively. Perfect primary balance is produced at the expense of a torque reaction along the crankshaft that would do very nasty things to mere two bearing cranks employed in British twins, but produces a much smoother engine in such devices as XS400 Yamahas and old CB450 Hondas. Suzuki also use this option in GS400/425 engines when they remove all sensation from the engine by the silly provision of a gear driven balance shaft. Honda, a long time advocate of 180 degree cranks, copied Kawasaki in their Superdream series to produce a powerful engine that could self destruct when neglected.

Having wasted a huge amount of space and time complaining about the awful engine design, I now have to admit that the Z400 is a jolly pleasant bike to ride. Not fast or economical, you understand, but the kind of bike that's easy to get along with, feels reasonably secure and never intrudes far enough to cause complaint. It has a little bit of character without all the trauma of cycle and engine parts leaving a messy trail of debris or the need to pack a box full of spare parts. Of course, the Kawa is no tool for street hoodlums - all of the bike's performance parameters rapidly begin to fall apart once the extremes of power and handling are encountered, but then there are a whole host of interesting middleweights that offer much more high speed insanity. The Kawasaki makes no pretensions towards being an out and out hustler and thus can, I suppose, be forgiven when it objects to such abuse.

The Z400 is an update on the KZ400, a design basically identical except for an extra gear and some minor mods to the engine that helped sort out the earlier bike's penchant for self destructing just after the end of the guarantee period. The Z400 was superseded by the Z440, which except for its higher selling price, is a much more useful and economical device.

But let's get back to the Z400. The engine developed the far from startling sum of 36hp at 8500rpm from a mere two valves per cylinder, operated by a single overhead camshaft via a set of rockers with screw and locknut adjustment that didn't need adjusting very often. Kawasaki had the decency to use long lasting, maintenance free gear primary drive (but then so did all their rivals) and a light but strong multi-plate clutch. Given the large dollop of mid-range grunt, use of a six speed box could easily be condemned as exceedingly silly, but it was easy enough to use and didn't fall apart at the same rapid rate as the five speeder fitted to the KZ. Given thirty grand on the clock, missed changes between first and second and difficult neutral selection are quite common. With forty grand on the clock, gear selection is a carefully planned action but the box has enough feel to it to let the rider compensate for wear.

Out on the road, the Kawa is happy enough to be stuck in fourth or fifth and can be used from between 25 and 85mph with hardly any complaints.Trying to go any faster wasn't a pleasant experience. Excessive vibes fron the engine start to affect petrol tank, footrests and handlebar grips. While this was a mere inconvenience at lower speeds and revs it quickly becomes rather nasty. Triumph twin owners could probably grin and bear it, but it's much worse than the secondary vibes from straight fours of more than twice the Kawa's capacity and power. At 90mph, by comparison, the sixties CB450 was alive but unconcerned, the GS400 was still electric smooth, the XS400 was beginning to throb a little and the CB400 was marginally smoother than the Kawa.

Pushing beyond 85mph also upset the Kawa's handling. Weighing well under 400lbs meant the Kawa should not have caused too many problems for either chassis or suspension, but the front forks and rear shocks with eight years and forty thousand miles of abuse, were lacking in both damping and springing. The result was a slight weave on flat straight roads, that became worse as speed increased, until when flat out at the ton the bike could require a car's width of road in order to survive. Throw in some bumps or worn tyres and speed wobbles are a natural result. It was easy to trip up the suspension when chucking the bike through sane fast, bumpy curves - the Z400 exhibited all the attributes of a NSU Quickly with a bolt or two loose when any attempt to really thrash the poor thing was undertaken. At least the Kawa could be relied upon to give some kind of warning and some degree of feedback before it acted out its suicidal urges. The Superdream led the pack as far as handling and ride went, closely followed by the Suzuki (lacking in feedback) and the Yamaha (quick rot suspension and dodgy swinging arm bearings). The Kawa ends up not far behind the Suzy, especially for those who don't travel too fast and like to know how the tyres are reacting to the road. 

At legal speeds the Kawa is perfectly acceptable. It feels very secure and its light weight make it a piece of cake to flick through heavy traffic and along country lanes. At these lower speeds even worn tyres and bumpy roads can be taken in their stride. As most of my riding seems to be done in wet weather, I was off quite happy to be pottering around on the Z400 in the wet, when I had no intention of speeding and needed only a bike that held no unpleasant surprises and wasn't likely to flip its wheels suddenly. The ability to stick it in one gear and control speed by the throttle was a welcome relief from some of the brutal devices that come my way, when touching the throttle often has the thing trying to spin the back wheel, and forward progress is a series of frightening lurches. In this department the Kawa beats the rest of its rivals.

It's a pity I can't extend such praise to the front brake. It's not the worst disc I've ever had the pleasure of using. It can be used with a great deal of impunity when braking in bends and it doesn't suddenly lock the front wheel without any warning. This is probably because it doesn't have very much stopping power. I shall refrain from spending this paragraph in extolling the virtues of decent drum brakes - by now you should have heard enough of my discontented mutterings on this subject - and concentrate on illustrating the silliness of 1970s disc brakes. The brake pads last for about eight thousand miles, or if you prefer to combine danger with disturbing screams from the front end of the bike (if not alarmed pedestrians) they can be taken right down to the metal after ten grand. As the latter course leaves some badly scored discs this could turn out rather expensive. A set of pattern pads that further impair braking ability can be found for around ten quid. An amusing hour can be spent screaming obscenities at motorcycle designers, next door's cat and local yobs while attempting to replace these pads without becoming a hospital patient. This is on a lucky day. Given a few thousand miles of winter riding, then the completely exposed and perfectly placed calipers will pick up all kinds of interesting pieces of grit that will seize up and corrode the brake. This is true of many bikes, but the Kawa suffers the faults without returning the kind of braking force that can be expected from a decent drum tens years its senior. I 'm only surprised that I don't see Z400s with heavily vandalised front ends...

While I'm in a bad mood I may as well go for the jugular by mentioning fuel economy. Oh dear, oh dear, I can't quite find the correct adjective to describe the way the Z400 consumes fuel. If I was being kind, I could compare it to the equally slow (ho hum) latest Honda CB350S. The Kawa would just about survive comparison. If I was being really nasty I could compare it to the much faster and older CB450. The Kawa would be shown up for the appalling engine design it really is. While the 45hp CB450 can average 70mpg , the poor old Kawa is hard pressed to better 50mpg even under the moderate use its chassis and engine confines its rider to employ. I managed to restrain my right wrist for long enough to find out the economy when pottering between 30 and 40mph, and was shocked to get just 60mpg. Cruising at 70mph returned 48mpg, thrashing the engine at the limits of revs and vibes returned 35mpg, although the latter figure has little relevance as such speeds can't safely be maintained for any length of time. Even if I confine myself to comparison with bikes of the same era, such as the Suzuki GS400 , the Kawa still loses out by a large margin. Blame that balance shaft, and the use of twin carbs in such a low power unit. The later Z440 develops more power and consumes less fuel.

Before Z400 owners tear up this magazine in rage, I'd better throw in some good news. This sentence has just closed down my brain. Good news? Ah yes, rear tyres. They seem to last for quite high mileages, someone's even claimed 15000 miles from a Roadrunner , but twelve grand seems a more representative mileage. The front goes for an extra few thousand miles. Even chains make it past twelve grand with ease, and well maintained jobs have almost done twenty grand. Oh yeah, the thing even looks quite neat in a classical way, stands out rather in these high tech days , the way all those British twins used to make Jap multis look so crass back in the seventies. But we all know that looks can deceive, don't we? The paint on the cycle parts is pretty good stuff, comes up quite well with bit of elbow grease. The frame's paintwork isn't so resilient; I seem to recall a friend's bike was spotted with rust after a mere two years. Chrome is in trouble after three years. Exhausts last a similar period before giving in to nature Engine life varies to such an enormous degree that I'm hard pressed to give any coherent information. This is probably nothing new.. try fifteen grand for something that's been thrashed and neglected from birth, 25000 for a bike given moderate treatment and maintenance, and about 45000 for the ideal owner who never breaks the speed limit and has swapped religion for bike maintenance. Any number of problems can cause mechanical mayhem rings, tensioners, valves, crankshafts, balance shafts... take your pick.

The Z400 only makes it as a very cheap hack. Try tuning the engine, it'll fall apart. Try uprating the suspension and you'll have to thrash the engine to make use of the new handling abilities, which will also make it fall apart. Use it as a slow commuter and you might lucky and get years of reliable service. But then you'll be suffering the same fuel consumption as larger bikes.

Hundred Quid Hacks: Yamaha RD200 and Honda CB200

Back in the seventies, when learners could burn around the streets on 250s, most Jap manufacturers reserved the 200cc category for slightly more sophisticated and sensible bikes. Thus both the Yamaha RD200 and Honda CB200 benefited from relatively mild motors, electric starts and reasonable economy. They tended to be purchased by experienced motorcyclists and to escape the harsh treatment attracted by their slightly larger brothers. With prices wrecked by the 125 laws, they represent bargain buys for cost-conscious purchasers.

The CB200 engine represents the final development of Honda's evolution of the small four stroke twin. It shares the same basic design as those early sixties twins that made Honda‘s reputation as builders of oil tight, reliable and high revving engines. A four bearing crankshaft supports two pistons that move in unison. A single overhead camshaft, driven from the centre of the crankshaft,  operates two valves per cylinder with screw and locknut valve clearance adjustment. Gear primary drive, through a multi-plate clutch, to a five speed box. The engine is only lacking in an excess of balance shafts to cure a non-existent vibration problem.

The RD200 engine is built along similar tough lines to the Honda. It doesn't represent state of the art two stroke technology, but Yamaha's decision to use a mild state of tune to overcome their engine's penchant for burning holes in pistons means that the RD can almost equal the Honda's reliability. The engine has the pistons moving out of phase, the usual four bearing crankshaft, gear primary drive, multi-plate clutch and five speed gearbox. Reed valves are placed between carbs and induction port, to allow reasonable port size while maintaining some kind of mid-range torque. As two stroke twins go,the RD200 is one of the better engine designs.

When new, Honda claim 18hp and Yamaha 20hp. The effect of 12 years use and over thirty thousand miles on either bike has blurred any distinctive effect such power difference might once have held. Neither bike has been rebored, tuned or given much more than perfunctory maintenance. The Honda needs its 1000 mile oil change and the RD its 750 mile ignition timing check. Otherwise, life is laid back enough to the point of boredom, the quest to blow the engines hindered by their sheer toughness and imperviousness to flat out riding.

The Honda is as happy at 30mph as at 75mph. Top speed is a true 80mph, an indicated 90mph. Flat out, the limits of two pistons moving up and down together with no balance shafts to overcome primary vibration, are felt as graunching vibration through the petrol tank and footrests. Backing off the throttle slightly removes the vibes, reducing top speed to just under a true 80mph. Continual riding in the vibration zone seems to do no harm to the engine. 

The RD has a similar top speed - a little faster in favourable conditions and a little slower up hills or against a strong wind. The engine is always smooth, there's no obvious vibration to warn against straying beyond the redline. The only sign of hard use, the clouds of blue smoke that haunt the trail of the Yamaha. Below 40mph,in top gear, the RD is caught out by a handful of throttle, when the motor stutters before clearing out the engine. It's far more responsive in fourth at low speeds.

The Yamaha can take the Honda from a standing start, the CB needing 40mph on the clock before it starts to catch up with the RD. Either bike can burn off silly young men in Golf GTis in town, but both are in trouble in the motorway fast lane.

The Honda also gets into trouble when there's a combination of high speed and bumpy roads. The main problem, the front forks which despite thicker oil, lacks sufficient damping to adequately control the reasonably taut springing. It never develops into a speed wobble, just lacks precision and can let the bike wander way off line. The geometry of the CB helps high speed stability and makes it difficult to lift the front wheel from a standing start. Standard rear shocks are useless after a couple of years and have been replaced with Girlings, which while not very special or high tech, keep the back end under control. The swinging arm bearings need replacing every 10000 miles.

The RD is rather more precise than the Honda, with much better front forks and a slightly stiffer tubular frame. The Yam suffers a slightly weak swinging arm and bearings that need replacing at the same mileage as the Honda. The Yamaha's geometry is less concerned with stability, concentrating on flickability and high street credibility. A handful of throttle and a slight pull on the bars has the front wheel high in the air. On worn tyres the RD can come close to converting an 80mph weave into a violent speed wobble. The blame lies with that weak swinging arm.

Country roads see the bikes evenly matched. The Honda's superior midrange torque is pitted against the Yam's agile chassis. The Honda is further hindered by a transmission that loses most of its precision after 30000 miles. It was all too easy to miss a gear if the change was hurried. The Yam's gearchange was largely unaffected by ageing, retaining a nice quick action. Neither bike could select neutral from a standstill. It was just as well that the Honda didn't need too many changes to maintain respectable speeds.

Handling problems on the CB finally came to a head on a narrow country lane. The Honda was doing sixty down a steep hill that curved sharply to the right at the bottom. The sudden emergence of a van around this bend meant there was hardly any space to pass. Braking hard, shift down the box and aiming for the left side of the road produced a bike out of gear, twisted forks that didn't absorb the bumps, and a bike that couldn't be directed with any kind of precision. The face of the van driver looked as frightened as I felt. Ramming the bike into the bank of earth along the side of the road was the only sensible thing to do. The van driver must have had the same idea because a small gap emerged. The Honda survived with a large clump of earth attached to the footrest.

To be fair, both these bikes are twelve years old and their low weight helps save them from any real nastiness. But the Yamaha has more feel and is more precise. Wet weather riding was fine, except that both bikes could lock their rear wheels with absurd ease. With SLS drums like that who needs disc brakes on the rear wheel? The Yamaha didn't acquire a disc front brake until '76, but the TLS drum was just as powerful, had brake shoes that last for over 15000 miles and the drum was as effective in the wet as in the dry. The same couldn't be said for the single front disc of the Honda. Wet weather lag was only bettered by the sudden application of brake pads once the water had been cleared off the disc. The disc needs to be dismantled every five thousand miles to avoid seizure of the calipers. The pads last for 7500 miles. It just about equals the power of the RD's drum. The joys of fashion...

The Honda is way ahead of the Yamaha in the fuel economy stakes. The RD isn't too bad for a two stroke, averaging 65mpg, but it must still lose some fuel straight out of the exhaust port. The Honda manages to average 80mpg. This is better than some of the much slower single carb CD versions. Flat out riding increases that figure to 70mpg, whereas the poor old RD is hemorrhaging badly at 45mpg. Timid right wrists will get either bike to return just under 100mpg. The RD has a larger tank with just over two and a half gallons, giving a range of 140 miles before reserve. The Honda has room for just two gallons and a range of 130 miles. The filter in the CB's petrol tank can clog up easily, making reserve useless, which further reduces the range to 110 miles

Neither bike is comfortable for more than a hundred miles. Forward mounted footrests make use of the passenger pegs mandatory for flat out cruising. The Honda has the least comfortable seat, one that retains water and has too soft foam. The CB200 engine is more durable than the Yam. It can keep going to 40000 miles, when it might just get away with a rebore - usually it needs a new camchain and camshaft, while some cylinder heads are so wrecked that a new one needs to be found at the breakers. Lack of regular oil changes are the only thing to ruin the engine in low mileages, when the accumulated engine swarf wrecks the camshaft bearing surfaces, camshafts and pistons.

The crankshaft is so tough that it outlives the rest of the engine. With fifty grand on the clock, the clutch and gearbox cease functioning; using new parts to renovate them will cost more than the original price of the bike. Contact breakers last for ten to twelve thousand miles, although nifty use of a file can extend their life for another few thousand miles.

Most RD200 engines are in trouble by thirty thousand miles, some struggle on to as much as 35000 miles. The roller bearing crankshaft is the most expensive item on the repair list. Supplied with only intermittent oiling in true two stroke fashion, it needs a complete rebuild. The engine will also need a rebore. The gearbox and clutch don't seem much affected by high mileages. Contact breakers need replacing around 7500 miles and spark plugs need changing every three thousand miles to avoid difficult starting. The electric starter is out of action by 40000 miles. Both engines are straightforward to maintain and to strip down. The Yam needs a strobe for the timing, but otherwise they are just as simple as British bikes.

The Honda escapes the camchain tensioner horrors of some other Honda models, while the Yamaha avoids the overheating and over-stressing of some of the other RD models. There are big bore kits (240cc), wilder camshafts, two into one exhausts and improved air filters available for the CB200. Stock silencers can last for four years before they disintegrate into a pile of ferrous oxide. Pattern silencers work quite well , although don't expect the increased. noise to lead to better performance. Two into one systems seem to upset the carbs, as do non-standard air filters. One bike, with 240cc kit, two into one exhaust, open carbs and high lift cams, managed to shift the CB up to a true 90mph, unfortunately, economy was shattered to a mere 45mpg, and vibration was a fair imitation of a BSA B25. The whole balance of the bike had been wrecked. 

The Yamaha isn't all that well supplied with tuning goodies. Most of the performance kit manufacturers concentrated on the 125 and 250 twins. It's possible to find some expansion chambers and perform the usual ministrations to the engine with a file. The usual result of tuning the engine is to lose mid-range power, hole or seize pistons and increase fuel economy to Kawasaki triple levels. The easiest way to make the RD200 go faster is to fit the 250 engine. Silencers last for much longer than the Honda, thanks to a liberal coating of oil applied to their internals by the inefficient two stroke engine process. The Yamaha and Honda engines both benefit from being left as stock as possible. The manufacturers achieved a decent compromise between economy and performance, that is easily lost by the addition of non-standard parts. Decent shocks, forks and tyres are the only sensible additions. 

Tyre wear was similar on both bikes. The Honda came out worst with just 8000 miles from a rear Michelin, but on other tyres it matched the Yamaha's 14000 miles rear and 15000 miles front. The Yamaha and the Honda are similar in concept but different in feel. The RD is more fun on country roads and in town, the Honda more relaxed and stable on long motorway journeys. The sharpness and smoothness of the two stroke are eventually overwhelmed by the durability and efficiency of the four stroke.

Buying from new the Yamaha would probably have won, but in the hundred quid hack stakes the Honda is the better buy, not least because there are still plenty of low mileage bikes with only a few owners available. Still, for just £100 the RD can be such good company.