Yamaha Xs750 Sf
YAMAHA XS750 SF
CYCLE WORLD TEST
Meet Our New Long-Term Touring Test Bike: a Special Triple.
Competing against all the companies in the world that produce 750cc motorcycles is not an easy task, but a task which Yamaha has approached with a certain degree of novelty. Rather than offer another four cylinder sports bike. Yamaha created the dohc Triple in 1976 and the same basic bike still is offered in 1979.
In 1976 the Yamaha Triple was less unusual than it is today. At that time Suzuki was still producing a collection of two-stroke Triples, Kawasaki had only just replaced the H2 Triple w ith the dohc Tw in and the only Fours were the Hondas and the big Kawasaki. The most unusual feature of the original Yamaha Triple was the shaft drive, a feature offered in 1976 only by BMW. Moto Guzzi and Honda with the G I... 1 (XX). jÉia-...
In 1979 all the other big Japanese companies offer mid-size Fours, which are chain driven, and all the major motorcycle manufacturers offer shaft drive bikes, most of which are large-displacement machines. If anything, the unusual mixture of three cylinders, shaft drive, and 750cc displacement is an advantage for the Yamaha 750. It’s a special package.
Beginning with that special package. Yamaha has treated the motorcycle to its ow n customizing and created the 750 Special. Cow boy handlebars, a rounded peanut-shaped gas tank, more front end rake, leading axle forks, short mufflers, a stepped seat, restyled instruments, and a clean rear fender are what make a Special.
Yamaha wasn’t the first company to chopperize its motorcycles. Norton tried selling 850 Commandos with high-rise handlebars. Kawasaki had the FI D version of the Z-l. But those were more muscular, more brutal machines which lent themselves to chopperism. The Yamaha 750 was a touring bike, with shaft drive, relatively soft suspension, and a lowkey kind of power that doesn’t lend itself to intimidation.
What kind of touring bike does a Special make? And how does Yamaha’s Triple perform as a touring bike? To find the answers we've procured a Yamaha XS750 Special as our new long-term test touring bike.
The Yamaha Triple has always been a popular motorcycle around the Cycle World office. When it was introduced, it quickly found a place on our list of IO Best Motorcycles for 1976. Since that time it has been changed and improved, though not all changes have been improvements.
Engine changes on the Triple would have to be considered improvements. Shortly after the original 747cc engine was introduced the 3-into-1 exhaust system was changed to a 3-into-2 system on the 7502D model.
Then came the XS750E in 1978 and more engine changes. 1 he exhaust system change had moved the vibration band of the engine to a less annoying road speed and improved performance. For 1978 the compression ratio was bumped from 8.5:1 to 9.5:1. the cam timing changed, electronic ignition added and more precise carburetion was used. The results were substantially more power, a higher redline (9000 rpm for the E model as opposed to 7500 rpm for the D model) and a cleaner exhaust to meet emission laws.
For 1979 the emission level must drop some more so the compression ratio was dropped to 9.2:1. Yamaha still recommends using regular gas in the 750 and the test bike ran fine on regular or unleaded. For 1979 the engine mounts were modified to minimize vibration felt at normal highway speeds. Vibration control on the Yamaha Triple has gone through several phases. The original XS750D was subject to an irritating vibration at normal highway speeds. Then the 2D model came out and the vibration period was moved to different highway speeds, smoothing out typical touring speeds. When the more powerful E model was introduced, vibration had increased again. Now with the F the vibration is more controlled.
Suspension development has gone through similar refinement. The original XS750 offered a moderately plush ride, followed by the even softer ride of the 2D that had a longer travel front fork and softer spring and damping rates on the rear shocks. For 1978 the rear springs were stiffen shock damping increased considerably and a three-position front fork spring preload adjuster was added. Rear suspension has remained the same on the 1979 models, but the Special gets new' leading axle front forks, still with the three-position preload adjusters.
Despite the suspension changes, the 750 Special s suspension isn’t noticeably better Tan previous Yamaha 750 suspensions. The rear shocks offer excessive compression damping, making for a stiff ride, even though the spring rate is about right for a solo rider and a tad soft for two-up riding. Even with full preload, the back end will easily bottom on rough roads with a passenger aboard. The front forks are better, cushioning shocks reasonably well. Overall. the Yamaha’s suspension, particularly the suspension on the Special, could use some improving. We’re looking forward to trying some suspension fixes during the next year.
What gives the Triple its charm is the engine. The rocking beat of the 120° crankshaft is pronounced at low engine speeds. It’s a crisp sound coming from the two short mufflers, slightly louder than the standard XS750, but pleasant and not offensive to our ears. As engine speed increases, the individual beats smooth out until the only sound is a gentle hum at highway speeds.
Add to the sound the power characteristics of the Yamaha 750 and the results are quite pleasing for a touring motorcyclist. The Yamaha probably has more power below 3000 rpm than any of the other 750cc bikes, save perhaps the Triumph Bonneville. Riding the Yamaha on a dayto-day basis, a rider gets used to accelerating from standstill with the engine just above idle, using the engine, not the clutch, to accelerate the bike. It’s easy to ride in town with the engine running under 3500 rpm and the bike in 4th gear. Compared to any other Japanese 750, the Yamaha feels more comfortable, at the same speeds, one or two gears higher.
When the engine was revised to produce more power, the power was gained at high rpm, but with little sacrifice of low-end power. Still, the XS750, in its present form. is half a second slower in the quarter mile than the quickest of the Japanese 750s. Its quarter mile time is in line with the 650 Fours. In real-world situations, the Yamaha may be faster with its roll-on superiority. but at the drag strip it’s not in the hunt.
For touring use, the power characteristics of the 750 are welcome. The output shaft gear ratio on the E and later models was changed to 3.582:1 from 3.262:1, increasing engine speed at 60 mph by 400 rpm. Strangely enough, the revised gearing of the newer Triples works very well. At 60 the Yamaha is turning at 4522 rpm, calculated, and at normal freeway speeds in our area the Yamaha is running at a busy 5000 rpm, hardly the sort of engine speed for relaxed touring. But it works. The lower gearing improves acceleration in all gears and makes 5th useful for accelerating on the freeway or climbing hills. While the> high engine speed may seem disconcerting at first, it puts normal highway cruising above the engine vibration period and smooths the ride. And with the 9000 redline, the Yamaha is geared for a top speed of 122 mph. though it would only pull 114 mph in our half mile top speed run.
Less appealing is the action of the gearbox while shifting. Even with the clutch properly adjusted there is a loud crunch when the Yamaha is shifted into 1st when cold. Upshifts are also noisy and the shift lever occasionally sticks in the up position after being shifted into 2nd. preventing or slowing the shift to 3rd. In all gears there is too much drive line slop, making speed changes jerky, particularly at low speeds. The CV carbs don’t help, responding too quickly to throttle changes, particularly when the throttle is closed.
But on the open road there is no problem with drive line snatch. The Yamaha simply hums along, the vibration muffled by the rubber-mounted handlebars and footpegs. Rubber-mounted handlebars do lend a degree of insecurity to the Yamaha’s handling, but the bucko-bars don't encourage ear-holing anyway. After a 500 mi. day the cushioning is welcome.
Actually, the seating position is fine for long days in the saddle. The handlebars work especially well with a windshield or fairing, enabling a rider to sit comfortably
without reaching for the bars or doing a push-up. Without a windshield or fairing though, the handlebars just aren't comfortable and they inhibit sporting riding.
Sporting riding isn’t the sort of use the Yamaha Trip 1 e invites, particularly the Special. There's a low-speed clumsiness to the Special which, w'hen combined with the unusual seating position, makes low speed maneuvers a tad uncomfortable. At speed the Yamaha is steady and goes like an arrow, requiring more-than-usual amounts of effort to turn. Evaluated on its own. the Yamaha’s handling is certainly acceptable for any ordinary use. It’s just that the other 750s, the Honda and Suzuki and Kaw'asaki and certainly the Triumph, all handle noticeably better.
With a better seat the 750 Special could actually be considered a comfortable tourer. The shape isn’t bad. In fact, as far as stepped seats go, the 750 Special has one of the better shaped seats, both rider and passenger having fairly flat surfaces on which to sit. It’s just that the padding is too firm and the overall size is marginal for luxury-size Americans.
Yamaha’s standard 750 has a similarshaped seat which includes a molded tailpiece. On some rack or saddlebag units the lift-up seat can’t lift up without removal of the rack or saddlebags. On the Special, the seat can lift up, even with a rack installed.
For most touring use, the 750 proves a worthy mount. For heavy-duty loads, however, the Yamaha can be overwhelmed. With a GVWR of 960 lb. and a load capacity, with a half tank of fuel, of 414 lb., the weight rating isn’t too bad, but when the weight is concentrated at the rear, the rear tire can be overloaded. Unlike many of the other larger displacement motorcycles on the road, the Yamaha can’t be fitted with a larger rear tire because the driveshaft-filled swing arm limits rear tire clearance. A 4.00 x 18 is as large as the Yamaha will take.
If the Yamaha could take a larger rear tire, it would have one. big tires being part of the chopper image, you see. Yamaha has spent considerable time and money on market research which supports the Special stvling. Surveys showed that the largest block of motorcyclists preferred the “normal" motorcycles but that large blocks of motorcyclists liked the style of the Specials.
It turns out the Specials have been enormously successful. Nearly half of the 750 Yamahas sold are Specials. Over half of the 650s sold are Specials and it’s too early to see how sales of the 1100 Special are going. Of the three Specials, the 750 has made the best transition. The clean styling of the 650 and the easy comfort of the standard 1100 are just right as they are. Except for the adjustable suspension of the 1100 Special, the other Specials don’t gain anything in the transition. The 750 Special does gain.
Despite Yamaha telling us the standard and Special both have 4.5 gal. gas tanks, the Special tank holds 5.1 gal. And the Special tank has two petcocks so there is a larger reserve.
There are other advantages to the Special. The mufflers are especially nice, small enough so as not to interfere with saddlebag mounting, ending ahead of the axle so tire changing is easy. We just wish more motorcycles came equipped w'ith mufflers like these. The headlight is special. It’s a 55/60 watt halogen lamp. The light is bright, the pattern well defined and it’s nice not to have to put in our own quartz bulb.
Both standard and Special Yamaha Triple have an assortment of features such as the turn signal canceller, mag-style wheels, and triple disc brakes. The brakes, by the way, are powerful, easily regulated and provide excellent stops when dry, but lose braking pow'er when they’re wet.
Although we haven’t needed it yet, the 750 has a kick starter and we’re glad that it does. Another old-fashioned feature on the Yamaha w'e like: it can be started without the clutch being pulled in.
Yamaha's Triple is neither the fastest, nor the smoothest, nor the best handling 750 made, but it offers special features for the touring motorcyclist in either standard or Special version. We’re looking forward to the next 12.000 miles.
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YAMAHA XS750SF
SPECIFICATIONS
$2885
PERFORMANCE
