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Hot Rod - November, 1977 Print E-mail

Hot Rod Magazine Article

November, 1977

Highway 11



We have known for some time that Yamaha was going to come into the 1978 model year with a brutish, four-cylinder in-line shaft-drive superbike; we just didn't know until recently how big and how brutal the new model was going to be. When the successful XS750D three-cylinder shaftie appeared last year, a lot of people naturally assumed that a fourth 250cc cylinder would be appended to the machine to represent the company in the marketplace against the KZ1000, the Honda Gold Wing, and the impending GS1000 Suzuki. As a matter of fact, a prototype "XS1000" four-cylinder, triple-disc-brake shaftie was shown to members of the motorcycling press, and the Yamaha dealers, in January of this year, to resounding oohs and aahs.

      But that particular motorcycle never appeared - primarily because it never existed. Yamaha had led us all down the garden path, because the XS1000, even as it was shown during this past winter, was a ruse, never intended for production. What does exist, and what will be coming into the country in appreciable numbers starting next month, is that prototype, almost to a T, with the exception that the powerplant in it is a full 1100cc, pumping out 95 horsepower, thus making it the most powerful, and the fastest, production motorcycle you can buy. The XS1100 is capable of speeds in excess of 135 mph and 11- second quarter-mile times.

      The XS Eleven is one very modern motorcycle design, and its engine is at the heart of it. The four-cylinder, four-stroke DOHC engine features four huge Mikuni BS34 constant velocity carburetors, 9.2:1 compression ratio, transistor-controlled ignition with a vacuum advance system, several types of emission controls, rubber mounting of engine to chassis, and an internal electrical switch that shuts down the ignition system when the bike is leaned over at any angle greater than 60 degrees from the vertical. The cylinder head is completely different from that used on the three, with splayed ports, a different chamber shape and a modified valve layout. While the two powerplants share stroke dimensions at 68.6mm, the very narrow four uses a 71.5mm bore dimension (1101 cc total displacement) and shares only a handful of parts, such as connecting rods, with the three. Externally, the 1100cc four bears only a slight re- semblance to the 750cc three, with new cam boxes and a totally bright finish, as opposed to the flat black used on the barrels and cases of the 750. And the best part is that the rest of the machine is up to the same level of engineering sophistication as the dynamo-smooth 95-horsepower engine, an engine capable of putting this bike into the 11-second twilight zone, right off the showroom floor, or around-the-world touring.

      The chassis and suspension for the 1100cc superbike are derived from the latest version of Yamaha's 750 shaftie, the E model, which was given more power and lower gearing late in 1977, to improve its performance against other bikes in its class. Of course there is no other bike in the XS Eleven's class at the moment, but the 750E was a good starting place for the Yamaha engineers to build a frame and suspension. The XS Eleven, built to be both a superbike and a super touring bike, is quite long, 89 inches overall, with a 60.8-inch wheelbase, exactly three inches longer than that of the XS750E. The length distributes the machine's 610 pounds over a longer distance, and the increased distance between the wheel centerlines at the pavement helps the super-compliant suspension take the harshness out of bumps and ruts in the road surface. The front forks are rated at 6.9 inches of total travel, and the rear driveshaft/swing arm is rated at 3.15 inches of travel, both figures the same as the lighter XS750E. Another feature carried over from the 750 to the 1100 is the convenience of easily adjustable front fork spring tension. The top of each fork tube is fitted with a rubber cap, and once the cap is popped off, the fork spring tension can be adjusted harder or softer by inserting the tool kit screwdriver into the slotted adjuster, to compensate for added weight of windshields, fairings or other touring add-ons. The big 1100 is fitted with premium 3.50H19 front tire and a big 4.50H17 rear tire (at one point, Yamaha was going to fit the rear with a monster5.00H17 skin to handle the weight and the power of the machine, but the 4.50 tire was found adequate and substituted for the larger tire late in the bike's development program). The machine is rated at 5.90 inches of ground clearance with these tires fitted, and this figure is adequate for all but the most spirited street riding, which tends to put the exhaust pipes on the right side in touch with the pavement.

      They called this bike the XS Eleven because it has run legitimate 11-second quarter-mile times in this country-at Irwindale raceway, in fact-with an American rider aboard. And naturally, any big motorcycle with this level of performance built into it had better have the capability of stopping from high speeds as well. Yamaha saw to that by simply carrying forward the very effective, smooth and predictable triple-disc, dual-hydraulic brake system from the shaft-drive 750 models. The discs are slightly smaller and thinner than the 10.5-inch units from the 750. The twin discs in front and single rightside rear disc attach to Yamaha's own seven-spoke "mag" alloy wheels, and these pieces go a long way toward establishing the XS Eleven as an esthetic force to be reckoned with. At this writing, the bright-engined, mag-and-disc-equipped machine will be available in only one color, Macho Maroon, with golden fuel tank and side-cover emblems contrasting the brightwork. Other concessions to styling include four-into-two megaphone mufflers with integral "expansion chambers" for a slight power gain, a 5.25-gallon tank with internal gas gauge sender, a rectangular headlight, and matching rectangular tach, speedo and fuel gauge housings, a fiberglass sculptured tailpiece and an integrated, stepped saddle. The saddle is mounted stationary, allowing XS Eleven owners to select from a wide range of Yamaha and/or aftermarket saddlebags and cargo boxes without about clearance worrying hinged seat. Minimal storage is found behind the key-locking left side cover, and that's all there is.

      Riding the XS Eleven is nowhere near as violent as the availability 95 horsepower would suggest. The engine is ready whenever the rider is, ready to pour it on from any rpm level in any gear, from 25 mph to redline in high gear. Yamaha has done an excellent job in matching the engine's power curve to the gearbox and final drive ratios, as well as in noise control. The air inlet system, the mechanical noise from the engine and gearbox themselves, exhaust noise and tire noise were all studied carefully; and all have been dealt with to the max. This is one of the quietest truly quick and fast bikes there is. We observed two other test riders on XS Elevens, drafting at full chat in high gear no more than 30 feet apart, from a vantage point less than 40 feet from the machines, and we were astounded at how quietly they flashed past us. Obviously these machines meet all current state and federal noise drive-by regulations by a comfortable margin.

      Improvements in rider comfort are many on the Eleven. The bars are swept back comfortably, the seat/bars/pegs relationship excellent for upright cruising positions, as well as high-speed crouching, and the square-housing instrumentation large enough for easy flash readings. The tailend of the fuel tank is narrower than the 750 tank, and it slopes downward farther to meet the saddle than does the tank on the 750, making the riding position more "in" the bike than "on" the bike, and we call that an improvement too, considering the awesome capabilities of this machine. The saddle itself is thick and dense, affording all-day riding comfort and necessary support, and the new clutch and brake levers, with dust covers, are a pleasure to use.
The XS Eleven prototype was as nearly perfect a machine as we've encountered, offering comfort, quickness, speed, smoothness, great good looks and a whole long list of extra features that any rider will appreciate. Handling, too, was very good for a 600-pound machine with shaft drive, right on up to the point where rear suspension softness caused some quirky moves in tight, very-high-speed corners, bringing the back end of the machine around. But we hasten to add that even experienced riders will find very few places on public roads that it can't handle.
At the moment, the XS Eleven has not been priced for the U.S. market. It will certainly cost more than the $2198 asked for the XS750E. Even if Yamaha adds another $800 for the XS Eleven, it will still be under $3000. And that price begs a question: When was the last time you could buy a $3000, 135-mph, 11- second car? You never could, of course, and you never will. That's why the Yamaha XS Eleven has got to be the high-performance buy of the year for 1978.            HR

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