Tuesday 16 December 2014

Yamaha XS650

The first time I ever rode an XS650, I was taken in by its immediate feeling of security on the road and was therefore shocked to my very core when I went wild on the throttle and the bike went even wilder on the tarmac. By wild I mean a real vicious old tank slapper that had the bars slamming from stop to stop. This on a 1976 model of low mileage and in generally tip-top shape; it wasn't until later that I found out how bad things could turn on earlier XS-2's.

The easy way out of such madness is to slam on all the anchors and scream your way back into sanity. This is okay as long as you have the right kind of muscles, the Yam turning into a total bronco ride whilst the chassis tried to sort out the various forces pulling it apart. The wobble usually comes in at around 95mph, usually when the road surface turns bumpy, and doesn't really sort itself out again until the velocity is down to about 50mph!

The coward's way out is to simply avoid going above 90mph when the XS650 rides along the road in a veritably stately manner. This easy out doesn't apply to the custom versions, 75mph about the most you'd want to try whilst the XS-2 would manage 80mph without threatening a wobble, but only if the shocks and forks were up to spec, which on anything worn even mildly certainly wouldn't be the case.

The real way to deal with the Yam's inbuilt instability's to loosen one's grip on the bars and let the wobbles die out naturally. Fighting the bars, or gripping them tighter, just feeds the wobble, increasing its amplitude. It takes a certain amount of courage to slacken off one's grip but after the first couple of times it becomes second nature and the knowledge that it actually works rather than throwing you down the road makes it a lot easier to contemplate.

One friend on a similar bike was full of the belief that the way ahead was to accelerate through it! It has to be said that by 95mph the XS650 begins to gasp for breath and complain about such heady revs by churning out enough vibration to have the tank thrumming between the rider's legs. Getting the bike beyond the ton required some effort and time; too much to draw the bike out of its wobble.

As my mate found out to his cost. He tried to both fight the bike into submission and accelerate through the speed wobble, a combination that sent the Yamaha into a frenzy of self destruction that included wobbling across several lanes of highway, much to the amazement of the cagers! He reckoned that it felt like the headstock was about to snap off, a feeling I could well understand under the slightly less deathly wobbles that I'd experienced myself.

Anyway, the wobble threw the rider and bike off the road, into a steel barrier and thence bouncing down the tarmac, destroying itself and everything in sight. The XS is a heavy bike, mostly made from hefty steel, so can cause an awful lot of carnage. The rider was thrown clear of the debris, wasn't run down by the out-of-their-heads cagers and merely escaped with a severe bruising. He always was a lucky bastard.

This kind of debilitating madness adds to the mythology of the breed and the idea, that along with all those old British twins, it takes a real man to ride and master them! As I mentioned, this is in direct contrast to the initial impressions, at least on the later XS650's, which have all their madness totally muted at low speeds. The wake-up call all the more dangerous when it comes in without any warning.

For all that, the chassis is generally toughly made, can survive both violent and mild throw-offs with nothing more than a bit of kicking straight of the extremities. Rust can eventually, after say 80,000 miles, begin to eat into the shocks' mounts, threatening to break up the swinging arm (which is also heavily stressed by the power and mass, like a paperclip being worked back and forth) and I know one guy who snapped off the down-tubes when he hit the side of a bus at a mere 30mph.

The swinging arm apart, rust doesn't seep from out under the paint, it just gets a grip after the paint's been chipped or worn down by good old wear and tear, something rubbing against it over a decade or so. With a bit of work, the chassis can survive several decades, though many Americans replaced the whole mess with an aftermarket frame that had some decent support around the headstock and swinging arm areas, not to mention much better steel.

One problem with such an upgrade, the lighter but stronger steel employed doesn't do much for vibration absorption and it's a rare non-standard component that survives for any length of time even on a standard XS. I've had horns, crash-bars and seats break up on me in a matter of months, the designers of the bike obviously going to extreme lengths to mute the full effects of two large pistons moving up and down in togetherness, which goes a long way to explaining why the bike weighed in at a 100bs more than rival 650cc British twins.

Though some of that mass helped to limit the handling, it also added to its indestructible nature, taking out the bane of British biking, a total lack of reliability. Having owned many British twins that turned really fierce at five thousand revs, the Yam was always a blessed relief. Push the XS harder, skirting with seven grand on the rev counter, the old girl begins to thrum away but the power runs out before it has a chance to turn nasty and there was something just plain wrong in trying to get the bike through the eight grand barrier, in, say, second or third. Learning the hard way on old British twins meant that I was never inclined to push my luck into regions where valve float and double vision vibration ruled.

The basis of the engine's strength is an old Honda trick of supporting the meaty crankshaft on four massive roller bearings that can take extreme abuse, 100,000 miles not unknown, especially in the XS650 which was detuned from 54 to 50 horses. One strong rumour is that a knackered starter motor can take out the main bearings but I've never come across an example of this in real life.

Complementing the strong crank, an OHC design obviously inspired by sixties Hondas but with superior bearings and a better camchain tensioner. Age does turn it very rattly but this isn't necessarily a sign that it's about to fail, many fifty thousand milers sounding like a washing machine full of nuts and bolts but running fine regardless. It's dead easy to forget that the camchain does in fact need the odd tensioner tweak but we're talking ten thousand miles rather than a thousand (or five hundred miles on sixties Hondas).

The only real area of weakness in the top end's the piston rings which could go down in as little as 15000 miles. More than anything, though, this was down to a bad batch in late model XS650's and should be rare on the secondhand circuit (having been largely fixed by now). It should be noted that the combination of a cheap rebore and pattern pistons doesn't last very long but is usually given away by a smoking exhaust and a bike that trembles heavily on the centrestand.

Of course, such excessive vibration might just be down to the fitment of an 840cc piston kit. This churns out the torque and power at a level that will give 850cc Commando owners pause for thought, but becomes something of a vibratory old heap when ridden at speed. Gone is the settled, contented feel of the stocker, both in power delivery and stability. Using all the power coming out of bends, for instance, will have the back end swinging from side to side in such a fierce manner that it feels exactly like the swinging arm is breaking up.

Go the capacity upgrade route, then make sure an alloy swinging arm, Koni shocks and relatively modern forks are fitted - otherwise you won't live for very long! These additions make good sense even on a stocker as anything more than a year old wears not at all well. And the brakes are very dire even when new.

The front discs, twins on the XS, are some of the worst I've ever come across. The only brakes I've ever experienced that are designed so that worn-down-to-the-metal pads actually pop out as you're riding along! The clanging noise as they did a fast exit made me think the front end was about to collapse, causing a massive swerve to the side of the road that perplexed and annoyed following cagers, not to mention myself! The missing pad was nowhere to be found, had to rely on the useful engine braking and somewhat wooden rear SLS drum.

As might be expected, the ancient calipers reacted poorly to my attempts at stripping them down to their component parts, the whole rotted mess seemed to have coalesced into one furry alloy form. Having already bought a new set of pads it was with the usual disbelief that I found myself with a cracked up caliper. Not the kind of essential component to repair with Araldite. Not if you want a long and prosperous life, that is.

Braking is pretty crucial on these kind of bikes and the weak, vague stockers are far from the ideal. Because of a lack of ground clearance it's dead easy to pile into corners far too rapidly, find the undercarriage digging in and scraping away until something catches, a whole new line suddenly inflicted on the rider. Manhandling 500lbs of madly wobbling metal ain't exactly my idea of fun but most of the time the bike pulls out of it.

The worst that happened to me was turning the XS into a rampaging 40mph trail bike, the front wheel digging in and me being thrown over the handlebars, which being relatively flat and narrow items didn't catch on any sensitive bits of my anatomy. The bike was a whole lot more civilised after I'd fitted an XS900 front end, the new found stopping power rattling the steering head bearings!

Only thing was, the brakes were so sensitively fierce that I dared not touch them when banked over in bends, as it would whip the front end up to the vertical and have the poor old beast charging for the nearest ditch, hedge or cage. Luckily, using moderate engine braking didn't upset the bike to any appreciable degree.

Having owned no less than seven XS650's, I can say that the handling does respond to a cunning mind and upgraded suspension components. The harsh reality, given its mild power output and excess of mass, is that something like a GS400 can whip its rear quarters, albeit with a lot more work on the gearbox.

It's worth noting that old XS650's run to very vague gearchange actions once selector wear gets beyond a certain point. Old hands of the breed don't find it a particular problem, can feed the lever in ever so gently but first-timers usually end up in a mess of false neutrals and missed changes. Shortlived drive chains (about 5000 miles) don't help matters, though primary drive is by a long-lived set of gears that don't really cause any problems.

The sweetest gearchange on an XS I ever came across was a low miler Special. This was about the only svelte element of the whole machine, though it was fine as a laid back cruiser if you didn't mind a 75mph top end. Limited by some dire handling antics, weak steering head and naff geometry. Actually worse than the infamous XS-2, its lack of brakes matched only by its lack of ground clearance.

Took me all of a week to decide to relocate its engine into a very tired, as in 110,000 mile, XS650. This bike had served well in the unlikely role of a long distance commuter. I'd made my own fairing, which whilst its looks deterred all but the most desperate of thieves actually gave an exceptional amount of protection from the elements without taking up a lot of space. All it needed were a few rounded edges to finish it off, but the bike was nicked (amazingly) before I got around to that.

Another area that looked a bit naff but worked wonderfully well was the King and Queen seat. Stock saddles were never very comfortable and flattened out after about 12000 miles of wear. The replacement proved exceptionally comfortable, at least until the seat base broke up from the vibes. Once experienced, going back to the stock saddle was literally purgatory.

Another XS weak spot's the standard exhaust system that rusts from the inside out and the silencers can fall off without much warning as they rust around the circumference, helped along by the vibro-massage effect of the engine thrumming away. Even with half of one silencer missing it still runs, albeit with some frantic choke juggling.

The power is so mild that just about any set of cans suit the bike. The carbs, by the way, rarely need a balance, wearing into a permanent setting. I favour a pair of old sixties Bonnie silencers, which give the bike a very authentic sounding blare. Strangely, they rust away much more merrily than on British bikes. Those of an indulgent nature usually end up buying a replica stainless steel system that sorts out the rust problem once and for all.

Yet another area of possible failure on ageing XS's is the electrics. The field energized alternator needs battery power before it will generate any electricity so a dead battery means a very dead motorcycle. It's quite easy to flatten the battery on cold mornings when the cut-out switch on the handlebars plays up, the motor refusing to even hint at firing. A problem easily solved by removing the switch from the circuit, but only an option if you know about it.

There's a really ancient regulator design with authentic mechanical cut-outs, inspired by the Morris Minor school of engineering. In its favour, it rarely fails totally and can be played around with merely by some adroit screwdriver work. Great for roadside breakdown credibility. Because of the nature of the alternator it's not easy to upgrade the electrics. On the good side, the ignition points last for ages and rarely need any adjustment, though electronic ignition is an option - first kick starting and closer to 60mpg than the stocker's 50mpg. With electronic ignition, a fresh airfilter and freer pipes it's possible to better 65mpg. A stock XS650 does 50mpg pretty much regardless of what you do to the throttle.

Oddly, the slightly more powerful XS-2 managed 60-70mpg in stock form, possibly down to its dire handling above 80mph; or more likely to a freer breathing cylinder head design, not yet ruined by the emission fascists.

It also weighs about 30lbs less, more power combined with lower mass giving a much more urgent feel than the XS650, which at best could only be described as stately - yet, it gets you where you want to go fine and is well suited to modern roads and their highly policed status.

The real killer with the XS-2's is white knuckle speed wobbles. It can either start weaving heavily then switch into a vicious wobble or the mad oscillations can come out of nowhere, at speeds as low as 80mph. The ridiculously stock high and wide ape-hangers help not one jot. At least the bike has a bit of a reputation for highway self-destruction so you're half prepared for the onslaught of madness. Still, it has a rare level of wicked handling that has to be experienced to be believed. Heavy bracing of the swinging arm pivot helps more than a pair of Triumph forks (another popular addition, as well as flimsy and soggy stock forks the front disc is even bigger crap than on the XS650).

Despite the ongoing fear of being thrown off without any warning I found the XS-2 an enjoyable bike to hustle, at least I was never terminally bored, always some unexpected trauma waiting down the line. I bought one XS-2 that had done 83000 miles for five hundred quid, expecting it to go terminal in a few months - it certainly made enough noise!

But at 123000 miles it was still clattering away and capable of putting 115mph on the clock if you wanted to play die or dare! The most I ever saw on a Yam 650's clock was 118mph, flat out on an XS650 with Bonnie pipes - it was running taller gearing than stock and took about three miles to build up to its terminal (an apt word if ever there was one!) speed.

Usually, the ton-ten is the most you can sensibly expect, most riders not wanting to do more than 100mph - the vibes and handling being the major limiting factors rather than any worries about the engine disintegrating. As far as stock components go, nothing falls off even when run flat out - unless they have started to rot, when the vibes wreck them rapidly (exhaust, seat base, etc).

The highest mileage XS I've seen is 145000 miles! A one-owner job, never ridden at serious speed - the owner used to go all nasty when asked about the speed wobble because he'd never experienced it himself for the simple reason that the bike hadn't gone over 75mph. Hard ridden bikes begin to suffer around 75000 miles, the first signs a wrecked gearbox and then smoking exhaust.

Prices range from five hundred notes for a barely running dog to about two and a half grand for a prime example. 1500 notes will buy something with a perfectly good engine, some useful suspension and brake upgrades, and loads of life left in it. Throw in the occasional oil change, you can probably ride it for a year or two and then sell on at a nice profit. Original XS-2's are the most expensive but the least useful for hard riding. Classic status calling!

 
M. T.