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Yamaha

Zero

   

Yamaha XS 850G

 

 

 

 

Make Model

Yamaha XS 850G

Year

1980-

Engine

Air cooled, four stroke, transverse three cylinder, DOHC, 2 valves per cylinder.

Capacity

826
Bore x Stroke 71.5 x 68.6 mm
Compression Ratio 9.2:1

Induction

3x 34mm Hitachi

Ignition  /  Starting

Battery powered triggered  /  electric

Max Power

79 hp  57.7 kW @ 8500 rpm

Transmission  /  Drive

5 Speed  /  shaft

Front Suspension

Air assisted telescopic forks, 175mm wheel travel.

Rear Suspension

Swing arm 4-way adjustable damping, 99 wheel travel

Front Brakes

2x 267mm discs 1 piston caliper

Rear Brakes

Single 267mmdisc 1 piston caliper

Front Tyre

3.25-19

Rear Tyre

4.00-18

 Wet-weight

258 kg

Fuel Capacity 

24 Litres

Braking 60 - 0 / 100 - 0

13.3 sec / 98.2 mph

Two years into its short life, the XS750 had lost much of its early reputation as a high-performer: still having better-than-average handling, for the cc class, the three had been overtaken in the horse-
power race by developments among 750-4s from the other manufacturers.

For 1980 Yamaha overbored the 750 by 3mm to achieve 826cc, and in the XS850 were able to offer a three that was fully a match for any similar-capacity four, and not a few 1000s.

The extra power of the 850 was not, of course, the result simply of additional volume; the original cams had been reworked for more lift and dwell, the carburettors increased in size to 32mm (and the make changed, from Mikuni to Hitachi), the crankshaft strengthened.

The gearbox was beefed up, and a large Hi-Vo chain installed for primary drive.
A preload-adjustable front fork and rear units with normal five-position setting gave handling that was at least as good as that of the lower-powered 750 . . . significant achievement in view of th 125mph potential of the new model.

Road Test 1979

Of the big four Japanese manufacturers Yamaha have been the most innovative in recent times. They remained aloof as their main rivals battled to produce ever more powerful machines. Yamaha opted out of this performance race to produce such machines as the SR500 single, the XS750 triple and more recently the refreshing XV750 and 981 cc TR1, Japan's first attempt to build classic in-line vee-twins.

While other manufacturers were hell-bent on performance alone Yamaha's independent, common sense but exciting approach won much public respect, illustrated when the XS750 was voted machine of the year by Motor Cycle Weekly readers in 1977. Such reward is no doubt one reason why the XS750 still survives, albeit in the uprated XS850 package.

The luxurious XS850 offers a sensible, but in no way boring style of motor cycling; it is a cosy, physically undemanding and untiring top gear workhorse - engage fifth as low as 17 mph and you can forget the gearbox for the day. With deft right wrist movements the rider is the complete master.

The power plant is super-smooth, showing its worst discord - minimal at that - through the footrests at 4,000 rpm, 60 mph in top. This disappears again as the rev counter needle swings round to the 9,000 rpm blood line.

The increased capacity of 826 cc is derived from sliding pistons from the XS1100 four into larger 71-5 mm bores. The 850 is virtually three-quarters of the 1,102 cc straight four as the two also share an identical 68-6 mm stroke.

The XS850 boasts Hitachi constant-velocity carburettors - standard equipment on some Japanese cars, but the first occasion these fuel meters have been fitted as standard equipment to a production motor cycle. They are pressure die-cast instruments, a common manufacturing process in Japan though not in Europe, made within more stringent tolerances than the Mik-unis of the 750 as well as providing more precise carburation.

A three-notch lever on the left-hand 34 mm choke carburettor enriches the mixture for first time starting and this could be lowered to a normal-running horizontal position after a brief warming up.

Running with 9-2 to 1 compression pistons, maximum power from the double overhead-cam motor is boosted by 12 horsepower more than the 750, to 79 bhp at 8,500 rpm.

Oil consumption - 500 mpp in our last XS750E test, and one of the main bones of contention - is reduced 100 per cent on the 850 by modified oil rings. She also wears an oil cooler.

A logical progression from the seven-fifty, the XS850 is beefed up in its transmission to absorb the extra power and modified where necessary to eliminate some of the seven-fifty's weaknesses. The Hy-Vo primary drive chain is increased in width from 1 to 1-25 in, and the seven-plate clutch, which retains its light movement at the lever, is stronger to cope. A new clutch damper is also fitted to reduce noise. Cog-swopping is sweet

and precise throughout the improved box, in spite of the complex drive chain through middle, spur and bevel gears to the shaft. It is marred by an unavoidable clonk when engaging first gear.

The results after taking the more potent model through its tests at the MIRA proving ground were somewhat disappointing. The chunky triple was down by two mph on its smaller brother, in spite of the claimed power increase, and was also heavier on fuel. A redeeming feature is crisper acceleration, the big-bored triple shaving a half-second off the 750's standing-start, quarter-mile figures and so lifting the terminal speed above the ton barrier at 101-62 mph.

Allowing for the extra power needed driving through the shaft system, a mean top speed of 118-5 mph is not scintillating, although in its capacity bracket it still keeps the Yam amongst the leaders.

In price, speed, acceleration and overall fuel consumption there is very little indeed separating the Yam from its closest main road rival, Suzuki's GS850 four.

Emphasis is on a touring/sports model, not an out-and-out roadburner, but Yamaha appear to have gone overboard with the tall gearing. Lying prone on the tank, the 850 should in theory have pulled maximum power revs of 8,500 rpm, which would have produced 124 mph in top. As it was, the three-cylinder tore down the straight as fast in fourth as top with the rider prone, and with the rider sitting up it proved four mph faster, at 107-87 mph in fourth rather than the lowly 103-94 mph recorded in 'overdrive'.

Wide and bright on main beam, the larger 200-mm headlamp offers a discriminating light

but is disappointingly dim when switched onto dip to avoid dazzling oncoming motorists. Indicators are operated by Yamaha's familiar self-cancelling switch and control levers are neatly protected by rubber shrouds.

Not so intelligent, though, is fitting the pillion grab rail integrally with the seat. The rail needs to be separately bolted to the top location for the rear suspension units, for with over 5,000 miles on the clock, and presumably numerous pillion riders hanging on, our test bike's seat had worked loose and was putting unnecessary stress on the lock.

Yamaha follow the present trend of selling the models without a kickstart, and provide a novel answer should you come unstuck trying to start the motor. They provide jump leads in the comprehensive toolkit, that also includes an oil level dipstick, to cover emergencies. Personally I hate having to rely on others for help . . . and who is to guarantee it will be available anyway!

The sensible large-capacity 5-3 gallon fuel tank (3-8 gallons on the 750) is a boon to the tourist allowing 200-mile stints in the saddle without stopping . . . good considering the 850 is heavy on fuel at 40 mpg overall.

That is a criticism directed not at the XS850 in particular, or Yamaha alone, but the vast majority of present-day machines. There are few economical exceptions.

The suspension is adjustable but I left it in its mid positions for all-round comfort, as you would expect of a long-legged mammoth mile-eater to diminish the punishment your body has to absorb covering over, say, 500 miles in a day.

The frame is similar to its predecessor, the XS750, but noticeably more spacious in the area between the rear of the wet sump, black-coated engine unit and the swinging arm pivot. There is far more air between the two on the 850, although the wheelbase is 0-5 in shorter at 58 in. Fork rake, 63-5 degrees and trail (4-3 in) are, however, the same. The compromise offers good handling which conveys confidence and security, if slightly vague feel.

A shortcoming is the steering which is light and turns too easily, wiggling on cat's eyes and lane markings. It also tends to drop the machine into corners at mid-range speeds. Switching body weight inboard helps correct the trait and you can hustle the 850 into fast sweepers with more verve and confidence now that new upkick silencers give the needed extra ground clearance.

The three into two exhaust sounds very appealing and it was noticeable that pedestrians, as well as the rider, appreciated the deep, mellow warble.

The new exhausts, their polished-alloy hanging brackets, the bulbous tank and larger headlamp, give the model its chunkier appearance, reminiscent of a BMW from some angles.

By doubling up, the horns are of course more audible if emitting still, too refined a high-pitched bleep. A more lusty blast is needed to disturb those fast lane roadhogs and would be more in keeping with the model's character.

Like the Laverda threes and BSA/Triumph triples, the XS850 produces an infectious charisma and while not rocking the motor cycling world on its axis with a sensational performance, it is a very impressive allrounder indeed. Unsophisticated and out-paced by glamour bikes flaunting over a thousand cubes, she might be overlooked by all but the discerning.

Those characters who probably get the most pleasure out of their motor cycling, will find the XS850 offers practical down-to-earth riding, and good value for money as the shaft-driven triple makes fewer demands in maintenance demands than comparable fours with chain final drive.

Road test 1979

 

 

 

NOTE: Any correction or more information on these motorcycles will kindly be appreciated, Some country's motorcycle specifications can be different to motorcyclespecs.co.za. Confirm with your motorcycle dealer before ordering any parts or spares. Any objections to articles or photos placed on motorcyclespecs.co.za will be removed upon request.  

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