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Cycle Magazine - January 1978 Print E-mail

CYCLE ROAD TEST

YAMAHA XS ELEVEN (1978E)

 

 


Do you want the most refined ride, the least fussy engine, and the quickest quarter-mile in motorcycling? This new Yamaha has it all.


 

It now becomes clear that in Yamaha's fight for a larger share of the highway market the XS750 triple was only a left hook. Now they've delivered a genuine knockout, their new XS11 four, and in this model we have a new King of Superbikes. The long-reigning Z1, though certainly not grown soft with age, has been decisively dethroned. Equally important, with the Yamaha Eleven's arrival, we have an expanded standard by which such machines henceforth must be judged.

Lord knows the earlier generation of Superbikes did not lack speed; it is an unfortunate fact that some of them offered little else, and some of us had almost come to believe that performance existed only in combination with bare-minimum civility. Yamaha's Eleven should banish that notion. It is by a solid margin the fastest, quickest Superbike we've tested; but even if its engine were a lot less strong, if the big Yamaha needed another full second to sprint through the quarter-mile, it still would be a tremendously impressive motorcycle. Take that much muscle out of certain other early-Seventies stormers and the residue wouldn't be worth having. That's where this new Yamaha breaks with the past, and whatever else may come to us next month or next year, no Superbike will ever again entirely be forgiven rude behavior because it reels in road especially fast.

Actually, broadened standard or not, there remains a lot of appeal in sheer straight-line performance and Yamaha has been stunningly successful in providing that quality in the Eleven. Nobody gets far riding the XS11 before they become acquainted with the fact that it's strong; we had ridden ours over hundreds of open-road miles before going to the drag strip and knew it was a bullet. However, we'd also weighed the bike and knew it was too heavy to be quick leaving the starting line, which is where some of the earlier Superbikes had earned their reputations as sprinters. In fact, the Eleven didn't launch itself like a dragster - but when it gets about 50 feet away from the line and finds its stride, what follows feels and looks like the combined effects of afterburner, rocket thrust, and The Force. Only one other showroom-stock Superbike we've tested has covered the standing-start quarter with an elapsed time under 12 seconds and that was barely, after several tries. Yamaha's Eleven didn't turn a time over 12 seconds. The example we tested gave us an 11.9-second first pass, and ran off 19 more without slipping over the 12-second mark. Our bike's best ET was 11.82, and its highest terminal speed was 115.38 mph, reflecting an incredible top-end charge. On a stickier strip our Eleven would have been maybe a tenth quicker, and a bit of oil mixed with the starting-line rubber might have made it a tenth slower; either way it's faster than anything we've tested before.

So the Yamaha XS11 is the new King of Superbikes, and its performance came as something of a surprise. We all saw the implicit promise of a Yamaha four in the XS750 triple introduced in June of 1976. That earlier shaft-drive model pleased everyone with its elegance and refined ride, but the triple's performance was a bit sedate and everyone wondered when it would get a fourth cylinder. We assumed the extra cylinder was coming, assumed it would have the same 250cc displacement as the existing three, assumed it would simply be added by a suitable lengthening of crank, crankcase, cylinder-block and head, and assumed it would give the resulting Yamaha "Thousand" performance almost equal to that of the big Kawasaki four. Our final assumption was that an XS1000, when it arrived, would be an extremely nice motorcycle but nothing performance-wise to set everyone's heart aflutter. That's a total of five assumptions, and we missed on all but the first.

Yamaha didn't create an all-new engine for the XS11, but what they did amounts to much more than slapping another cylinder on the triple. The XS750 has its timing drive at one extremity of the three-throw, 120-degree crank, and the power is taken off the opposite end. In the four, both the power and timing drives are located at the crank's center, and everything else has been rearranged accordingly. The only common major parts are the connecting rods and the valves, valve springs and cam followers.

Even where parts are shared between triple and four, it's hard to determine which engine is doing the sharing. Yamaha has an upgraded triple, and we don't know whether, for example, the valves and valve timing were first created to make the triple perform like other 750s, or were developed for the XS11 and subsequently incorporated into the earlier model. Either way, the Eleven engine emerged from the process with an impressive amount of muscle. For practical reasons (Webco's dynamometer brake is rigged for chain drive) we are not yet able to take horsepower readings from shaft-driven motorcycles, but it's possible to estimate engine output fairly closely by using drag-strip speed and test weight as indicators. Yamaha's literature says the Eleven engine delivers 95 brake horsepower at 8000 revolutions per minute, with a 66.5 pounds-feet torque maximum at 6500 rpm; we think that's much closer to reality than most such claims. We'll note here, too, that serious power begins at about 3500 rpm, and that the engine will pull strongly well beyond the 8500 rpm redline.

A number of interesting features are to be found inside the engine. People with an automotive background would find the plain-bearing crank a familiar but somewhat puzzling article: it's the sort of lightly-counterweighted forging you'd find in a GM engine - except for having a pair of sprockets at its midsection, and strangely spindly main-bearing journals. There's a reason for the small-diameter main journals. Plain insert-type bearings will carry enormous loads but suffer if the bearing/journal surface speed is too high; that speed rises rapidly with bearing diameter. Large-diameter journals are a necessity in an automotive crank, which has the drive taken from its end and thus needs a lot of torsional stiffness. Yamaha's choice of crank-center drive reduces the stiffness requirement and allows the use of small, efficient main journals. We mention this rather esoteric item because it's engineering at a subtle level, and the kind that makes as much difference as the number of camshafts and carburetors.

Another subtlety has been applied in the Eleven's combustion chambers. Most of us have been taught, one way or another, that "hemispherical" chambers are good. They are in old-fashioned long-stroke engines with low compression ratios. But in big-bore, short-stroke designs the classic "hemi" combustion chamber configuration creates a problem: high compression ratios can be had only by making piston crowns tall, thick and convoluted in shape. Such pistons are heavy and absorb too much heat from the combustion process. Yamaha has adopted an interesting solution to this problem: a "polyspheric" chamber. They cut spherical-section pockets for the Eleven's 36-millimeter intake and 31mm exhaust valves, take an overall spherical-section cut over the whole bore area, trim flow grooves around the valve seats, and machine a final relief where the spark plug nose enters the chamber. That's a minimum of six individual machining operations just to form one combustion chamber, and this has to be expensive. But it does let them use slightly-crowned, light (211 grams) pistons and still get a 9.21 compression ratio. Again, it's something the owner can't see (and might not appreciate if he did) but still is a worthwhile feature.

The rest of this engine is fairly straight-forward, with two-piece automotive connecting rods and everything held in die-cast cases in typical motorcycle fashion. The two overhead camshafts are driven by a roller chain and work the valves via inverted-bucket tappets, which are topped with large shim discs available in graded thicknesses to provide a means of clearance adjustment. Oil (the recommendation is for 20W/40 SE at ambient temperatures above 40 degrees F.) is supplied from a trocoidal pump and fed through a disposable filter. Oil and filter changes are recommended at 3000-mile intervals, after break-in.

Our test bike's cam chain loosened, noisily, before we'd ridden 500 miles and in adjusting the tensioner we found a potential point of confusion. The adjustment requires only loosening and retightening a nut, but the tensioner is on the engine's forward side, and we thought, briefly, that we might be dealing with a "tight-side" device and would have to rotate the engine backwards to move the chain slack in the right direction. Wrong: the Eleven's engine rotates backwards, and that's why the tensioner is on the cylinder block's forward side.

Although the Yamaha Eleven taken as a whole is a "first," if only because it's both fast and civilized, the bike has in its makeup only one genuinely innovative feature: its ignition system. Yamaha's advertising probably will stress that the Eleven's ignition system is transistorized, with no mechanical breaker-points to replace periodically. There are plenty of motorcycles for which that may be said. The difference, favoring the Eleven, is twofold: first, that it has an inductive transistorized system; second, that it's the first to be fitted with an automotive-type manifold vacuum controlled timing advance mechanism. The first of these is a triumph of engineering judgment over what is trendy; the second will be misunderstood by most people, and dismissed as unimportant by the rest. In combination, they'll do more to make the Yamaha Eleven owner's life pleasant than all the overhead camshafts and zoomy exhaust systems ever invented.

You can expect to hear someone say the Eleven has "CDI ignition"; it doesn't. The conventional breaker points have been replaced with transistorized switching, but the system otherwise is the same sort of inductive arrangement Charles Kettering invented back in internal-combustion's infancy. You wouldn't want to have it any other way. Capacitor-discharge ignition (CDI) is fine for two-stroke engines, in which resistance to plug fouling is a primary consideration; CDI's problem is that the sparks it produces tend to be of such extraordinarily brief duration that they do a poor job of lighting the engine's fire. Inductive ignition systems take a few milliseconds longer to work up spark-level voltage, but their sparks are much more energetic and long-lasting. Thus, Yamaha's choice of inductive ignition for the Eleven is as wise as their decision to provide solid-state, transistorized triggering. The system's transistors feed current to the coils at all times, except for the fleeting moment when its rotating magnetic pole piece (which it has instead of a breaker cam) causes a field shift in a pickup coil. For that moment the coil's primary current is interrupted, and spark voltage is produced in the same manner as with any other inductive ignition system. The sole difference, between the Eleven and previous inductive-ignition Yamahas, is that this new four has been blessed with stronger coils.

The Eleven ignition system's second important feature, and one that's unique to motorcycles, is the vacuum-actuated advance/retard mechanism. Actually, there hasn't been an automobile produced in at least 30 years without some form of inter-connection between manifold vacuum and ignition timing, simply because spark advance otherwise has to be compromised between the conflicting demands of power and economy. Engines running under slight throttle openings have a thin, low-pressure mixture in their cylinders, and they don't run efficiently unless the fire is started long before the piston reaches top dead center. Much less ignition advance gives optimum results at large throttle openings. Yet, all motorcycles but the Eleven effectively have a fixed spark advance, with a centrifugal device to retard the timing for easy starting. And their off-idle timing has to be compromised, with enough advance to give reasonably good efficiency under cruising conditions but not so much as to cause detonation when the rider uses full throttle. The Eleven we tested had 10 degrees of static ignition advance, and another 26 degrees from the centrifugal mechanism, which adds up to the 36 degrees other engines of similar configuration have needed for maximum power. But then there's also 16 degrees built into the vacuum-advance device, and that pulls the timing around to 52 degrees BTC when the bike is cruising along at freeway speeds. Wind the throttles open, and it drops back to the power-setting; roll off throttle, and it auto-advances for economy; use some in-between throttle position, and the ignition adjusts itself to suit conditions. It's a big step out of the technological Dark Ages, and one that's long, long overdue.

There are a couple of real-life benefits provided by the Eleven's polyspheric combustion chambers and load sensitive ignition system. One is that they make the engine relatively insensitive to fuel quality; pour in anything but a mixture of kerosene and dead rats and the bike won't complain. Second, and more important, the self-adjusting ignition system does so much to stabilize spark plug temperature that Yamaha has specified extended-tip plugs of a heat range two grades warmer than usual for motorcycles. The recommendation is for NKG BP6ES or Champion N8Y plugs, and after you've been slogging along in traffic for 20 minutes they still work like they never heard of carbon. Hot plugs stay clean at low speeds, and the vacuum advance/retard feature in the Yamaha's ignition helps keep them healthy when you switch to fast and furious.

Yamaha has done a lot to make the new Eleven go fast, and as much to make it pleasant at all speeds. The bike's seat is very wide and soft, and the riding position seems to work out near-perfectly for a broad range of rider sizes and riding styles. At first glance the handlebar gives the impression of being pulled back too much, a bit like wheelbarrow handles, but you should keep an open mind about such matters. We always figure that if the old double-tiller handlebar setup was good enough for George Roeder, it ill-becomes us to make early negative judgments about it. In fact, given the sheer length of the new Yamaha, there wasn't much choice when they started bending handlebar tubing: the bike has almost 62 inches of wheelbase and a flat, straight European-type handlebar would have you stretched prone over the tank looking like Russ Collins on his Extravaganzamaton. The pulled-back grips they've provided occupy the right pieces of space for a comfortable reach, and Yamaha has placed the footpegs farther to the rear, relative to the seat/bar locations, than is customary. That is to say, they have the footpegs unusually well-positioned.

A large part of the Eleven's appeal is the rider's perch it provides, which is sufficiently comfortable to please even those who find Cadillacs only barely tolerable when travelling long periods between rest stops. Two or three hours in the saddle? Nothing to it at all; the Yamaha is going to leave the manhood-through-suffering touring crowd wondering where the day went. Of course, there have been other comfortable seats and other strain-free riding positions, but these have not been offered in combination with anything near the size, weight and - of greatest importance - suspension refinement found in the Yamaha. Our habit has been to disparage sheer size and weight in motorcycles; we'll now concede that these can be used to the advantage of comfort. Distance between a bike's wheels reduces the disturbances that road irregularities cause at its middle; add weight above the springs and you reduce the bike's tendency to bounce just because that's what its wheels are doing. The Yamaha Eleven may have acquired these size/mass characteristics as a by-product of its big engine and serpentine drive-train, but it does not waste the opportunity they provide.

It's hard to say precisely why the Yamaha rides so well. Size and Weight aren't the whole answer, or the Honda Gold Wing wouldn't be so stiff-legged. Neither is it yards of suspension travel or magic springs. The Eleven's fork telescopes a total of 6.9 inches, and there's only 4.25 inches of travel at the rear axle (3.15 inches at the shock, multiplied by the geometry). And the bike has only two-rate springs, front and rear, with the stiffer rate being reached at 4.1 and 1.8 inches of compression, respectively. Some of the results surely stem from the use of low-friction bearing sleeves in the fork sliders, but the major factor probably is that Yamaha decided ride was important and went to work on it. This attention has made even the feisty little RD400 ride well, and it has put Yamaha's XS11 heavyweight in a ride-quality class by itself.

Ride isn't handling, and with respect to the latter it must be said that the Eleven comes up short of perfection. Our first encounter with it took place on Yamaha's own fast, swoopy test track outside of Hamamatsu. The XS11 belongs almost anywhere there's pavement - except fast, swoopy race tracks. Pushed to limits far beyond anything even the most lunatic canyon racer would consider reasonable, the XS11 displayed all the handling characteristics which seem to be endemic to high-powered multis, and then added some brand new ones. After the suspension fluids heated up (which took about two laps) the Eleven was capable of generating high-speed cornering oscillations vigorous enough to chirp the tires. The bike made us immediately aware of its disinclination to do more than one thing at a time. We could turn it. We could accelerate it. We could stop it. But we couldn't simultaneously turn it and slow it down (which is necessary in any decreasing radius corner), nor could we simultaneously turn it and accelerate (necessary in exiting corners). Once these lessons were learned the bike could be hustled right along - but we never really felt we could trust it not to whirl and bite. On the racetrack, the Eleven was a double handful; a mean double handful.

It's much better away from race tracks, which makes sense considering that it was not intended to race (Yamaha has other bikes for that - TZ750s). Even so, the Eleven isn't exactly a Ducati Desmo out on Racer Road. Maybe it isn't possible to get precise, taut handling in the same package with a refined ride; maybe, too, some of what we perceive as shortcomings in the Eleven's ability to handle twisty mountain roads really originates from pitting the next decade's power against the last decade's tires and chassis thinking. Still, once you get it slowed and stuffed into a corner, it manages the rest adequately. You don't have to wrestle with the steering, which is light enough to make you forget that you're dealing with 600 pounds of machinery, and while the bike feels a trifle loose and sloppy, it never does anything overtly hostile. Trouble, if you find it, will come because the Eleven can haul you up to a considerable speed in an unparalleled hurry, and there is not a road-legal front tire presently available that will provide the brake/pavement connection needed to cope with the predicaments you can discover for yourself.

It's possible, riding the big Yamaha, to make it into and three-quarters of the way around a corner - and then find yourself skating down the road, buffing holes in your hip-pockets, because you've used too much throttle, too soon. Yamaha has fitted the Eleven with a fine, fat rear tire (one with a 4.50 section, on an extra-wide, 2.50 x 17 rim) and it still isn't enough to take all the power, all the time. You try a big rush away from the apex of a turn, and it's easy to get horsepowered sideways in any of the lower three gears. This is a motorcycle that asks for some restraint on its rider's part and sends up plenty of distress signals before it runs out of patience. But the XS11 is prepared to punish heedless stupidity like nothing we've had since the days of Judge Roy Bean.

Even those riders who don't find their entertainment in hanging around mountain roads should approach the Eleven with a modicum of restraint. The bike will, after all, light up its rear tire like a dragster if given a full-throttle blast in first or second gear, and its highway passing abilities have to be experienced to be believed. We're all accustomed to watching for oncoming traffic when trying to pass a line of cars on two-lane roads; the Eleven accelerates so hard at 50 mph, even in fifth gear, that by the time you've zinged past a six-car clump, everything on the road is oncoming. One of our test riders says he passed a camper and three passenger cars at full-brisk, swung back into his own lane comfortably clear of a truck lumbering toward him, and had to use the Eleven's brakes hard to keep from parking it in the back of a pickup doing the double-nickel about a hundred yards ahead of the view-blocking camper. Fortunately for him, the Eleven's brakes are excellent: their effectiveness is slightly blunted by the tires-versus-weight factor but they're smooth, powerful and wonderfully controllable.

The Yamaha Eleven needs good brakes because it is fast and heavy and also because it's deceptive. Most bikes when gathering speed will give you plenty of notice with rising vibration and other signs, and most bikes have to be rowed faster with their shift levers. Not the big Yamaha, which vibrates scarcely at all except at low engine speed and doesn't seem to care whether you downshift. Give it throttle and it responds with lethal smoothness - like a falling boulder. The engine doesn't work up full strength until you've got the tach needle above 3500 rpm, but it will pull cleanly right from idle. You can slow the Eleven to 25 mph in fifth gear before it begins to need a lower set of cogs, and the fifth-gear surge it will give you at 55 mph is enough to pull more bend into that backswept handlebar.

Living with the Eleven in traffic will make anyone glad its engine will pull a tall gear, because the bike is at its worst at low speeds, at light throttle, in the bottom gears. This Yamaha's constant-vacuum, butterfly throttle carburetors are a little less "wall-switch" in their suddenness than most CV-type Mikunis we've encountered, but they still have too much of that old, familiar all-or-nothing response coming off-idle. And when you combine that with a no-flywheel crank, and the accumulated slack from the whole drive train (one Hy-Vo chain and its sprockets, five pairs of gears, and the typically-Japanese coarse-toothed transmission dogs), and the instantly available engine torque, you get a very high lurch potential. The least amount of lurch is produced by staying in fifth gear when you can and nicking back to fourth when you have to, and that's the style you quickly acquire.

The unusual amount of complexity in the Eleven's drive train probably accounts, too, for another of its less attractive attributes-which is a chattering, grumbling harshness felt while moving along with slow traffic. This harshness disappears at speeds above 45 mph, leaving only a trace of low-frequency vibration from the engine. There never is enough engine vibration to cause blurring in the rear-view mirrors; it's just enough to make itself felt, and fades almost completely above 4500 rpm in fifth gear - which unfortunately translates into a road speed high enough to turn on one of those red bad-news lights. Yamaha's XS650 twin was given a stronger crank to make it suitable for the flat-out European market; maybe they'll re-tune the Eleven's rubber-bushed engine mountings to move the vibration smooth-out point down below 55 mph. Actually, the strongest vibrations you can wring out of the Eleven, trying to make them happen, don't rate much above the level of a tingle. But we think that even the tingle can be banished from the normal cruising-speed range.

In all but a few areas, such as those already noted, the Eleven shows a high degree of refinement. The gear-change action is a trifle sticky, mostly on the shift into second, and you do feel the bike's weight when making a U-turn in the middle of a narrow street. Otherwise, riding the Yamaha is just a dream unless you let exuberance transform the experience into a nightmare. Good moderate-speed rear suspension damping does an exceptional job of keeping the heavy rear wheel/gearcase mass from wagging the Yamaha, and the free-sliding fork lets the front wheel devour bumps rather than feeding them into the handlebar. The clutch action is light and never grabby. Overall, and ignoring the benefits conferred by performance, the Yamaha Eleven is as nice a trip as motorcycles are likely to give.

Finally, as though the rest weren't enough, the Eleven is loaded with what your local automobile dealer would call "features." Yamaha's self-cancelling turn indicators have been with us for a couple of years now, they're included on the Eleven, and we still think they're terrific. Years of trying - not always successfully - to keep track of bikes' fuel reserves by odometer estimation made us appreciate the fact that the Eleven has a fuel gauge. Its fuel petcocks also have a "reserve" position, and because they are fitted with demand valves (which close when the engine is shut off), there's a third "prime" position, which bypasses the demand valving and is used in restarting after the fuel tank has been run completely dry. Not that many people will run out of fuel while riding the Yamaha Eleven: it carries more than five gallons of gas, and when ridden with reasonable restraint (behavior foreign to Cycle's test riders) will go a little over 200 miles without being switched onto reserve. The Eleven we tested averaged nearly 45 miles per gallon, and we're sure it would top 50 mpg while cruising at 55 mph. Super-lean carburetion? Probably not: starting was easy, with just a minute or two of the choke when cold, and the engine didn't seem cold-blooded enough to suggest a lean mixture. Our guess is that the excellent mileage is another benefit of the ignition system.

There was one missing feature: the underseat compartment we've come to expect in Japan's road machines. The Eleven's seat is bolted solidly in place (to avoid product-liability litigation?), and no other provision has been made for the storing of incidentals. If you can't get it in your pockets the Eleven wants you to leave it at home. There is a locking helmet-holder, and you'll find the tool kit hidden behind a lock-equipped left sidecover. Don't expect to use the tool compartment for storage: it's a close fit for the standard set of tools.

One of the tools provided with the Eleven is both a beauty and a mystery until you check the owner's manual to find out what it is and how it's used. The tool in question is a length of cable with a pair of odd-looking links at one end, a peculiar double-curved strap at the other end, and two totally indescribable ferrules sliding back and forth in mid-strand. We read the manual and found that this tool is to be used in conjunction with a short pry-bar to pull the rear suspension up while the bike's on its center stand, so the axle can be driven out over the right muffler. It's all a part of changing the rear tire, and those who buy Yamaha Elevens will become well acquainted with the procedure, The rear tire is caught between nearly-immovable weight and nearly-irresistible horsepower, and tread life suffers.

But you know, all the comments about tire wear and snappish throttle response and drive-line lash and race track handling notwithstanding, the Yamaha XS11 is the most appealing, enjoyable street motorcycle we've ridden in quite a while. It, is so civilized, so loaded with nice touches, so smooth and so contemptuously, casually powerful. You may question the morality of supplying, for a comparative pittance, a consumer item which is capable of going 136.2 mph in absolutely standard trim (electronically timed on Yamaha's test track); you may wonder whether a two-wheeled device, really needs in excess of 90 horsepower to move itself down the road; you may question the wisdom of matching competition-level engine performance with street-level suspension and chassis performance. But what you're left with, and what we're left with, is this: what can the motorcycle do? The answer, race track realities aside, is: everything. It can outhaul the latest Kawasaki Z; provide more ride comfort than a Gold Wing or a BMW, achieve between 45 and 50 mpg; behave itself acceptably in the mountains; and only rarely need maintenance. The Eleven is simply the most impressive street motorcycle our staff has yet tested.

As fond as we have grown of it, and as proud as Yamaha must be for producing it, we must leave you with a caution: no matter what the circumstance, and no matter how highly you rate your own expertise, treat this motorcycle with respect. If you don't you'll discover abruptly that a have reaped the whirlwind.


 

Make and model Yamaha XS Eleven
Price, suggested retail - $2989

PERFORMANCE
Standing start 1/4-mile - 11.82 sec @ 115.38 mph
Engine rpm @ 60 mph, top gear - 3790
Average fuel consumption rate - 44.7 mpg
Cruising range, main/reserve - 188/44

Load capacity (GVWR less curb weight) - 221.8 kg (488 lbs)
Maximum speed in gears @ engine redline - (1) 53.2, (2) 73.2, (3) 92.6, (4) 115.1, (5) 1 @4.7

ENGINE
Type - Four-stroke in-line four, air-cooled, twin camshaft cylinder head with roller-chain timing drive
Bore and stroke - 71.5 x 68.6mm (2.82 x 70 in.)
Piston displacement - 1102cc (67.2 cu. in.)
Compression ratio - 9.2:1 (full-stroke)
Carburetion (4) - 34mm CV butterfly-throttle Mikuni
Exhaust system - Four-into-two
Ignition - Inductive, magnetically switched, battery powered
Air filtration - Foam element, washable
Oil filtration - Paper element, disposable
Oil capacity - 4.0 liters (4.3 qts)

TRANSMISSION
Type - Five-speed constant-mesh, wet-plate clutch, shaft final drive
Primary drive - Hy-Vo chain and spur gear, 25/25 x 58/35, 1.66:1

Final drive - Shaft, with spur and two-stage bevel gears, 44/47 x 19/18 x 33/10, 3.26:1
Gear ratios, overall - (1) 12.08, (2) 8.78, (3) 6.94, (4) 5.58, (5) 4.77

CHASSIS
Type - Tubular full-cradle frame, telescopic center-axle fork, dual-shock, swing-arm rear suspension
Wheelbase - 1545mm (60.8 in.)
Rake/trail - 29.50/130mm (5.12 in.)
Brake, front - Hydraulic, two 298mm (i 1.73 in.) discs with single-piston calipers
Brake rear - Hydraulic, one 298mm (1 1.73 in.) disc with single-piston caliper
Wheel, front - One-piece cast, seven-spoke, 19 x 1.85 in.
Wheel rear - One-piece cast, seven-spoke, 17 x 2.50 in.
Tire, front - 3.5OH19 Bridgestone
Tire rear - 4.5OH17 Bridgestone
Seat height - 808mm (31.8 in.)
Ground clearance - 150mm (5.9 in.)
Fuel capacity, main/reserve - 4.2/1.0 =5.2 gal.
Curb weight, full tank - 273.6 kg (602 lbs')
Test weight - 348.2 kg (766 lbs)

ELECTRICAL
Power source - Alternator, controlled field Charge control
Alternator output regulation
Headlight beams, high/low - 65W/50W
Tail/stop lights - 8W/27W x 2
Battery - 12V 20AH

INSTRUMENTS
Includes 160 mph speedometer, 10,000 rpm tachometer, odometer, tripmeter, fuel gauge, turn indicator lights, high beam light, oil pressure light, headlight failure light
Speedometer error - 30 mph indicated, actual 29.41
Speedometer error - 60 mph indicated, actual 58.10
Odometer error - plus 0.6%

CUSTOMER SERVICE CONTACT:
Customer Relations Department
Yamaha Motor Corp., U.S.A.
6600 Orangethorpe
Buena Park, CA 90620
(714) 522-9444

 

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