The big boxer-twin BMW GS models have defined adventure touring ever since the introduction of the R80 GS in the early 1980s, and to this day they remain the benchmark by which heavy duty beetle-crushers are judged, as well as BMW's best-selling model.
But the fifth-generation R1200 GS has been in production, essentially unchanged, for nine years and 170 000 units, and the field was starting to get a little crowded with the advent of the Yamaha Super Tenere and the big Triumph Tiger.
It was time for a complete overhaul, starting with the air/oil-cooled 1170cc flat-twin engine, which now has a proper water-jacket for the first time, with vertical flow-through to the elements that are particularly exposed to thermal stress, ie the heads and exhaust ports.
The rest of the engine is still air-cooled, retaining the characteristic finning, while the two small radiators are inconspicuously tucked away.
Power is up to 92kW at 7700rpm and 125Nm at 6500.
The new engine is also in unit with the six-speed gearbox, another first for a BMW boxer, and uses a multiplate wet clutch in place of the erstwhile car-type single-plate dry clutch, which was proving a little fragile when subjected to more than 90kW and 125Nm under adverse conditions.
That made it possible to incorporate a slipper clutch to prevent rear-wheel hopping under engine braking, and to run the final-drive shaft down the left side of the rear suspension (which is the 'down' side of the bike when it is on the side-stand, thus improving the lubrication of the crown wheel and pinion gear in those vital first few seconds from cold.)
It also has the first 'fly-by-wire' throttle on a GelandeScooter, which BMW says “provides a significant improvement in terms of controllability and response”. Given that electronic twistgrips have thus far proven a little over-sensitive for smooth riding on rocky terrain, we'll take that statement under advisement until we've ridden one.
The fly-by-wire system does, however, make possible two (optional) extra features: adapting the engine's output to the ambient conditions by means of five selectable power modes - “Rain”, “Road”, “Dynamic”, “Enduro” and “Enduro Pro” - and, also for the first time on a GS, cruise control.
BMW's first in-unit boxer twin is housed in a new, all-steel tubular bridge frame with a bolt-on rear sub-frame and a longer swing-arm than the previous model for better traction on rough terrain.
The revised Telelever front and Paralever rear suspension is now available with optional, semi-active, dynamic electronic suspension adjustment, which monitors vertical movement via a spring travel sensor on each wheel and adapts the damping automatically, depending on riding conditions and what the rider is doing, by means of electrically controlled regulation valves.
It runs on special rims and tyres in 120/70 R19 front and 170/60 R17 rear sizes, with partly-integrated Brembo antilocking disc brakes, including two 305mm front platters with Grand Prix-style radial-mount four-piston monobloc callipers - a first on an off-roader - in front and a bigger-diameter (276mm, up from 265mm) rear disc.
BMW also claims a world first for the GS's new LED headlight with (optional) built-in daytime running light.
Also making its first appearance on an off-roader is the rotate-'n-twist multi-controller collar, which we encountered on the K1600 GTL tour-bus and found to be almost as much of a nuisance as the i-Drive on BMW's four-wheelers.
It's mostly used for operating the (optional) BMW Navigator IV satnav, so here our advice to car drivers is even more appropriate: pull over and stop before you fiddle with it!
Do the same with the screen unless you're on a long, straight tar road; it's adjusted by hand using an easily accessible selector wheel.
You will have to stop, of course, to adjust the rest of the ergonomics - and there's a lot you can adjust. The rider's seat can now be tuned for both height and tilt angle and the pillion seat can be shifted fore-and-aft to achieve the ideal distance between rider and passenger.
The new handlebars can easily be turned upwards to improve the standing position for off-road riding (together with a revised knee grip on the side of the 20-litre fuel tank). Adjustable footrests and foot controls match the bike to your riding boots.
One thing we wish we could adjust, however, is the bike's weight. BMW quotes 238kg, ready to ride but without fuel; that translates to just more than a quarter of a tonne with a full tank, an enormous weight for any motorcycle intended to be ridden off-road.
The new R1200 GS will go on sale in South Africa from the first quarter of 2013. Prices, as always, when they get here.
Engine: 1170cc Air/liquid-cooled boxer twin.
Bore x stroke: 101 x 73mm.
Compression ratio: 12.5:1.
Valvegear: DOHC with four overhead valves per cylinder.
Power: 92kW at 7700rpm.
Torque: 125Nm at 6500.
Induction: BMS-X electronic fuel-injection with two 52mm throttle bodies.
Ignition: Digital electronic.
Clutch: Hydraulically-actuated multiplate wet slipper clutch.
Transmission: Six-speed constant-mesh gearbox with final drive by shaft.
Front Suspension: Telelever cartridge forks.
Rear suspension: Paralever with hydraulic shock absorber remotely adjustable for preload, compression and damping.
Front brake: Dual 305mm discs with Brembo radial-mount four-piston monobloc callipers and ABS.
Rear brake: 276mm disc with Brembo dual-piston floating calliper and ABS.
Front tyre: 120/70 - 19 tubeless.
Rear tyre: 170/60 - 17 tubeless.
Seat height: 850/870mm.
Kerb weight (without fuel): 238kg.
Fuel tank: 20 litres.