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BMW R 80G/S

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Make Model

BMW R 80G/S

Year

1982

Engine

Four stroke, two cylinder horizontally opposed Boxer, pushrod operated 2 valves per cylinder.

Capacity

797.5 cc / 48.7 cu in.

Bore x Stroke

84.8 x 70.6 mm

Cooling System

Air cooled

Compression Ratio

9.2:1

Induction

2 x Bing constant depression carburetorss

Ignition 

Battery ignition 
Alternator Bosch 12 V/280 W
Spark Plug Bosch W 7 D / Beru14-7DU / Champion N9YC
Starting Electric & Kick

Max Power

37 kW / 50 hp @ 6500 rpm

Max Torque

56.7 Nm / 5.8 kgf-m / 41 ft lb @ 5000 rpm
Clutch Dry single plate, with diaphragm spring

Transmission 

5 Speed 
Final Drive Shaft
Gear Ratio 1st 4.40 / 2nd 2.86 / 3rd 2.07 / 4th 1.67 / 5th 1.50:1
Rear Wheel Ratio 1:3.20
Frame Double loop tubular frame with bolt on rear section

Front Suspension

Telescopic hydraulic forks
Front Wheel Travel 200 mm / 7.8 in

Rear Suspension

Monolever swinging arm
Rear Wheel Travel 170 mm / 6.6 in

Front Brakes

Single 260mm disc

Rear Brakes

200mm Drum

Front Tyre

3.00 - 21

Rear Tyre

4.00 - 18
Dimensions Length 2230 mm / 87.7 in
Width 820 mm / 32.3 in
Height 1150 mm / 45.2 in
Wheelbase 1465 mm / 67.6 in
Ground Clearance 175 mm / 6.88 in
Seat Height 860 mm / 33.9 in

Wet Weight

186 kg / 409 lbs

Fuel Capacity 

19.5 L / 5.1 US gal

Consumption Average

5.2 L/100 km / 19.1 km/l / 45 US mpg

Standing ¼ Mile  

13.8 sec

Top Speed

167 km/h / 104 mph

Road Test

Cycle World 1981

Cycle 1981

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For a company which had previously taken new model introductions lightly, BMW brought the house down in revealing their latest wonder, the R80 G/S. At BMW's invitation, over 30 curious journalists from around the globe were assembled in the historical city of Avignon, in the south of France. In a conference room deep within the massive medieval stone walls of the famous Palace of the Popes, which stands as one of the most impressive historical monuments in France, president of BMW's Motorcycle Group, Dr. Eberhard Sarfert and vice-president Karl Gerlinger, had the tough task of explaining the G/S's reason for existence. After all, what reasoning could there possibly be for producing a so-called multi-purpose bike weighing 400 pounds and sporting an awkWard boxer engine? Or better yet, what advantages or enticements could it possibly have over the current crop of lightweight singles? There were obviously none if you were to pit it head-to-head; but then the point was clearly stressed that the G/S was not designed to compete on the same turf against the familiar cluster of conventional "enduros," or against anyone else for that matter. In fact, BMW may well have dreamed up an entirely new and untouchable slot in the market solely for its purpose.

In looking at the whole realm of motorcycling, the Bavarians came to the enlightening conclusion that there was a definite dearth in one particular market area - "cross-country touring." They couldn't think of a dual-purpose contender which had the ability to supply long-distance touring comfort in conjunction with its off-road skills. Come to think of it, can you name a bike "ideally" suited for rambling over the Alaskan Highway or maybe down the Baja peninsula, a journey which would inevitably entail long miles of pavement and punishing off-road sections as well? When you consider all the elements there really isn't a machine which fits the occasion to a tee-so BMW went ahead and created one. In looking at the G/S's engine layout, its weight and size in relationship to displacement and its top-speed potential of around 100 mph, there's no question it possesses totally unique qualities, qualities which BMW feels make it virtually unrivaled in its field and for its intended purpose.

The creation of the G/S (the "G" stands for "off-road," the "S" for "street") was relatively easy for BMW, for its basic design had already been formulated through their off-road racing efforts. Oh yes, the factory has been involved in dirt competition for some years now, and lately they've been quite successful too. West German Fritz Witzel won the 750cc-and-over class in last year's German ISDT aboard a highly modified 800cc Beem-er which weighed in at a scant 300 pounds and pumped out over nine inches of rear wheel travel from it's Yamaha-style monoshock suspension. Similar factory BMWs were also used to capture their class win in the 1980 German and European Championships which are similar to our two-day trials. BMW simply applied proven street designs to the basic dirt machines and, presto: A dirt-going dual-purpose bike which could likely circle the globe without even breathing hard.

If you dissect the G/S's makeup you'll find it leans heavily toward the street. Starting with the slightly modified R65 frame, BMW added a massive 5.2-gallon steel tank which offers about a 250-mile touring range—more than any other dual-purpose bike in existence. Up front the G/S utilizes the same 7.9-inch-travel forks as the big street models. Nothing strange about all this so far, but wait! The G/S does indeed sport a front disc brake, the first motorcycle of its kind to do so. When you consider the G/S's weight and its hunger for speed it was almost a necessity. The Brembo fixed caliper is new this year to the BMW marque (all the '81 street models will have similar units) and is fitted with new asbestos-free semi-metal (metallic) brake linings which BMW claims increases braking performance in the rain by 40 percent. They're also a little lighter when compared with conventional lining and not as prone to heating up and smearing. The G/S's tires are rather unconventional too, as they were specially developed by Metzeler to handle speeds up to 110 mph.

On the other side of the coin are the G/S's appointments for the off-road world. It has plastic fenders and side panels, Akront rims (which will also facilitate easier tire changing than with BMW's traditional safety rims), an alloy skidplate protecting the oil sump and a nicely muffled two-into-one exhaust system which is lighter and provides more ground clearance over the standard street pipes. The G/S's final drive ratio has also been lowered to 3.36:1 (the R80 street model had a 3.2:1 rear end) for better off-road performance. However, the most unique dirt-oriented aspect of the G/S is its rear suspension system. It's called "monolever" and consists of a one-armed swingarm on the right side which also houses the shaft drive. The rear of the bike is supported by a single gas Bilstein shock mounted to the frame at a point behind the right side panel. BMW claims a weight savings of 4.5 pounds with the monolever design and says that it actually provides a 50 percent increase in torsional stability. It's quite obvious that this arrangement will also simplify rear wheel removal too.

If you're familiar with BMW tradition, you know that from year to year they never work too hard at extracting more ponies from the boxer engines. Instead they concentrate intensely on increasing its reliability and durability. Such is the case this year. The R80 G/ S's engine is basically their former street powerplant which is still rated at right around 49 horsepower at 6500 rpm. But it has undergone some internal changes common to all of the engines in the '81 line-up, changes which not only improve its durability but pose a significant weight savings as well. For example, the engine is fitted with novel galnikal-coated aluminum cylinders. This is a process in which the bore surface is impregnated with integrated crystals of nickel and silicone. Some of the advantages are lighter weight and better heat dissipation, but more important, it allows closer piston-to-cylinder tolerances which reduce oil consumption and wear. BMW couldn't elaborate on the expected life of the cylinders, but we expect it to be very high. And we hope so, because in effect, the cylinders will not be reborable. And here's an improvement we've expected for a long, long time: The G/S has an all new flywheel/clutch assembly which is, get this, 8.8 pounds lighter than previous units! The clutch assembly itself has been redesigned and BMW notes that this clutch requires less actuating force, it's easier to control, and that it has improved shifting as well. And if maintenance on a BMW is considered almost minimal now, it will become even easier since all the new Beemers are fitted with fully electronic, breaker-less ignitions.

What made this press introduction particularly interesting, and most of BMW's claims easier to swallow, was that we actually were able to sample the G/S's performance the day following the press conference. It was a 45-minute bus ride to the Hotel Ousteau de Baumaniere, just outside the quiet little town of Les Baux. Awaiting us were 25 shining G/Ss and a map outlining a 25-kilometer course—most of it pavement with a short section of winding dirt road.

Climbing aboard the G/S, the first impression is that it feels extremely light and agile - and what weight there is feels like it's only several inches off the ground. All the bikes had electric starters which are an optional extra on the G/S, but we were informed that all the G/Ss coming to America will have them as standard equipment. Everything BMW said about the clutch workings is true: it has a much lighter pull at the lever and engagement is much smoother. Out on the road the G/S gives every impression that it can burn up the pavement as quickly and easily as its bigger brothers. The suspension is soft and compliant, and we did notice the normal shaft-induced rise and fall of the rear end - which BMWs are famous for - had been exaggerated slightly by the increased wheel travel. Seating arrangement is quite comfortable and there is no question that the G/S has the capability to rack up miles and miles at a blistering pace.

The G/S's engine performance is quite a contrast over former BMWs. Due to the lighter flywheel, the engine gains revs almost instantaneously now and races for the redline with a newfound freedom. We were really impressed with the bike's acceleration too - it really feels like it has some oats. We took the liberty of doing some second, third, and fourth gear roll-ons against an R100RT and each time the G/S, with its lower gearing and lighter weight, leaped out in front like a scared rabbit - well, at least for the first 100 yards and then the big 1000 gobbled it up on the top end.

Naturally, when you throw 25 rival journalists together on a winding road in a country where there appears to be little traffic law enforcement, there's going to be some heavy dicing. And there was, which only confirmed the fact that the G/S is an absolute brilliant handling machine on curvy pavement. With most of its weight situated low, it flicks quickly through corners with absolutely precise steering accuracy. Ground clearance is virtually unlimited and the Metzeler tires can't be faulted for their road-holding abilities. And we wouldn't hesitate to pit the G/ S's braking performance against that of any other dual-purpose bike; it'd likely make fools of them. We must admit that at first we were skeptical of the monolever suspension. After all, asking one stock-bodied shock, mounted forward in the lay-down position, to handle over 400 pounds of Beemer is a pretty tall order.

Surprisingly though, it gets the job done—and so does the single swing-arm, because the G/S didn't give any indication of wiggling or wallowing when thrown down hard through a succession of bumpy turns. However, damping capacity of the Bilstein borders on the marginal. We stated to one BMW engineer that we could bet the shock goes away in a hurry under extreme off-road riding, and he unwillingly agreed. He quickly added, "We have an optional Koni shock (with remote reservoir) for more serious off-roaders."

And just how serious of an off-roader is the G/S? Well, since you know its weight, the answer should be rather clear. Yes, it's quite a raging handful in the dirt at a brisk pace. It's big and heavy and the soft street suspension gets eaten up quickly by even moderately sized ruts and bumps. Get the G/S airborn - even just a foot off the ground - and the landing is enough to jar your teeth out. You'd be better off taking a Brahma by the tail, but like the bull, the G/S has a set of nasty horns too—the cylinders. Now BMW may argue the fact, but believe us, with that engine layout the G/S is just plain clumsy and awkWard to handle in tight, slow-going terrain. Sure, the engine produces the low-end grunt and muscle of a tractor, but when you'd like to plant a foot down for steadiness, you can't because the cylinders won't let you. Consequently, it's difficult -if not impossible -to feel relaxed or even remotely confident flinging this mammoth around. And, as you might guess from looking at the puny-sized knobs on the Metzeler tires, the G/S has a tough time getting a firm hold on the turf, especially on marbly fireroads. Pitching the G/S sideways for our photo session was a real eye-opener, as the front end always wanted to slide before the rear. It's definitely not the kind of bike on which you'd attempt to conquer any tough terrain because its off-road capabilities are, in effect, very limited, the least of any dual-purpose bike we've ever ridden. We can visualize it casually rolling down a fireroad or exploring easy-going trails, but that's about as skillfull as it can get in the dirt.

But that only serves to reinforce what BMW has built - not your common run-of-the-mill dual-purpose machine, but rather a full-fledged street machine which can occasionally dabble in the off-road world. And with that, the G/S offers unique and exciting opportunities in a whole new field of riding, a field which it contests with virtually no rivals. How big that field is still remains a question, even to BMW, because they're only planning to make 5000 G/Ss in the first year, 15 percent of the production capacity.

Source MOTORCYCLIST/DECEMBER 1980