BMW R1100-1150GS

Launched in 1993 (with rectangular headlamp) but introduced to these shores in 1994, the R1100 GS 1085cc engine made a claimed and reasonable 80hp at 6750rpm, accompanied by a torque figure of 9.8kg-m at 5250rpm. Weight was a fairly hefty 243kg wet and a two-position seat sat the rider either 840 or 860mm above the ground. Suspension was by preload only adjustable single shock and Telelever at the front and preload and rebound adjustable Paralever at the back. Braking was attended to by twin 305mm floating discs and Brembo four-piston calipers up front, combined with a single 200mm unit and twin-piston caliper at the back. ABS made sure the combination didn't overwhelm the inexperienced or inept.

Later in 1994 the 11 received a new cylinder head gasket (retro-fitted to just about all models now) a smaller bash plate plus some changes to the oil system. It's worth noting that the 11 also received the first in a long line of changes to the transmission.

With 1995 there were a bunch of changes that included a change to the cylinder heads which gained an extra fin up from nine to ten. 1996 saw the usual change of colours plus a switch to a one litre (down to 24lt) smaller metal fuel tank and a rear sub frame attached to the gearbox. In addition there were more substantial bolts used in the rear subframe in an attempt to stop the frame breaking when subjected to extreme off-road use. Changes to the engine included smaller inlet and exhaust valves plus a quieter exhaust.

1997 arrived and so did a revised gearbox along with a new oil control thermostat inside the engine. The final drive housing gained an increase in breather bore size and the throttle and choke cable system was simplified. 1998 was highlighted by the addition of an improved sidestand, anodized wheels and a revised piston design that cut the engine's thirst for oil.

1999 was significant for being the year that the 11 was discontinued and the 1150 (with two round headlamps) arrived. As is often the case the final years are the best having been the culmination of continual improvement.

So to the 1150. Although the stroke remained the same at 70.5mm, bore increased to 101mm instead of 99mm allowing capacity to jump to 1130cc. As you'd hope power increased by a useful 5hp, but importantly the torque curve flattened out and that, in concert with a six-speed gearbox and the new Motronic 2.4 electronic management system, gave the 1150 an altogether more lively performance feel.

Naturally there was more to the new machine than just a bit more performance. A few of the important changes included stuff like a shorter lighter Paralever from the R1100S and better suspension to make the thing handle better. There was a hydraulic clutch to make it easier to ride, a lighter and more tucked-in exhaust to let it lean over further, and of course new gearbox mounts. All in all, the 1150 was the product of a slow and systematic approach to improvement. Typically BMW. 

ON THE ROAD
Starting a BMW twin can be a bit of a culture shock. Especially an oil/air cooled model. Not only is there the clatter of the starter motor assaulting the engine in an attempt to fling the pistons round but, once fired up there's a metallic rattle that sounds like the crankshaft has broken. This is normal, and once running the rattle goes quiet very quickly as the oil pressure builds up and the hydraulic cam chain tensioner does its stuff. First gear goes in with a light 'clonk' and from there the changes, both up and down are slow and deliberate rather than slick and quick. Not that it matters because both the 1100 and the 1150 share a prodigious amount of soft bottom-end torque.

Once you get rolling it's the view that gets you, lofty enough to have a commanding perspective of all the traffic shenanigans. As you'd expect the C of G is high even though the flat twin engine sits its mass low to the ground. The 25 litre fuel tank plus all the other ancillaries including the handlebars that seem "it was this big" wide reinforce the overall impression of strato bomber height. 

However, as you recalibrate your go-meter to accept that acceleration is adequate rather than vivid, you realise that the engine is not just smooth but ideally suited to the kind of work that the GS is pitched towards. Not only that, but all that height means that ground clearance is almost unfathomable and the level of comfort afforded by the enormous saddle (Note the word 'saddle' rather than 'seat') is truly impressive. Yes, you can spend all day travelling without needing the services of a surgical excavator!

While the saddle is undoubtedly comfy, the real unsung star of the show is the suspension. In truth, the springs are somewhat soft, but not cruiser type pogo-stick-on-an-old-mattress type saggy. The front Telelever that separates steering from braking works through its travel range with commendable smoothness and is a fine partner for the rear shock in ironing out the road hits and dips. Perhaps the only time the front-end encounters problems is when you hit a significant bump while employing the aforementioned ground clearance. Such an event will have the front wheel skipping sideways with an attention grabbing clunk.

The brakes on both the 1100 and 1150 are very good. Not exceptional, but very good. As mentioned, on the 1100 the ABS comes in too early. When pushing on, if you brake hard on a bumpy surface down into a tight bend, the ABS will sense the bumps as lock-ups and release the brakes. This can be very scary and has even caused some riders to come unstuck. The solution is to turn off the ABS before starting the ride, however the system reboots to a default 'on' setting every time the bike is turned off.

Running costs are amazingly cheap as not only are genuine parts surprisingly cheap (more on this later) but fuel turns to gas at the miserly rate of 22km/l and tyres last forever. 

IN THE WORKSHOP AND WHAT TO LOOK FOR
For reliable information we went to BMW specialists BMM motorcycles in Ringwood, Victoria and spoke to Chris and James, a couple of quietly spoken blokes who live and breathe boxer twins and between them possess a huge amount of practical knowledge. Most of the problems described here relate to the 1100 rather than the 1150, which has a brilliant reputation for reliability.

First up with any 1100 check the gearbox bearings as these can shuffle off at about 60K. The main culprit is the input shaft bearing, which causes oil leaks on to the single clutch plate. This will be readily apparent during a test ride, as the oil on the plate will make the clutch slip. The fix is to replace the bearings and seals and then re-shim, failure to do the whole job will start the process all over again.

Check the Paralever for play in the same way you'd check wheel and swingarm bushes. Any play will most likely be the Paralever pivot bearings in the pivot mount, although it's easy to convince yourself that the huge output bearing is the problem. When you replace any of these bearing ONLY use genuine BMW items as using aftermarket bearings will end up costing you big time - don't ask me how I know. A drive shaft inspection should be carried out after before any long trip.

If the engine's noisy, this isn't a problem as in all likelihood all that's needed is a good set-up and tune. This would include re-tensioning the cylinder heads, adjusting the rocker end-play and valve clearances. Other items that make a noise are throttle bodies that wear out or rattle due to a stretched throttle cable, a problem common to both 1100 and 1150. A lot of the problems that afflict the GS are the product of poor maintenance. Stuff like leaking cylinder head gaskets can be fixed with a later gasket but things like a defective electronic gear indicator you either live with or take the swingarm out to replace.

Service items are very cheap with a genuine air cleaner costing just $26 and oil filters costing $29, fuel filters $33 and alternator belts $27. Talking of alternator belts, find out when the last one was replaced. These can go with as little as 2000kms or 100,000 showing. They should be changed every 60,000 and neglecting to do it is asking for trouble.

Service costs by a reputable workshop such as BMM every ten thousand cost around $295 for a minor service and $550 for a major. However it should be noted that this includes checking and setting valve clearances to ensure that all other adjustments have the best effect. 

MODIFICATIONS
Probably the most significant performance modification that the 1100 can benefit from and one I can vouch for, is the addition of an oxygen sensor in the exhaust. This boosts midrange from 3000rpm significantly and for the cost of $400 represents excellent value especially as the standard quiet exhaust can be kept. After that a suspension freshen up or replacement transforms the soft and floaty feeling completely as well as allowing greater adjustability.

As for the 1150 models, a quality exhaust system from someone like Staintune or Leo Vince will boost power as well as providing a bit of Boom for the Beemer.

Tyre choice is important and currently Metzeler Tourance or Michelin Anakee dual sport tyres are the rubber of choice. If you need a more aggressive dirt pattern then try Continental TKC80s.

SUMMING UP
These days you can pick up a secondhand R110GS for as little as $7500. Don't be put off by high figures on the dial because the engines are good for at 250,000, mine had 140,000 on it a year ago. 1150s can be had for between $11,500 and $15,000, with the more specialised Adventure (shown in silver with metal panniers) going for another $3000. No matter which end of the scale, you'll get a solid piece of engineering, made to a high standard that will take you anywhere.

SPEX
ENGINE
Type: Air/oil cooled, , four-valve, four-stroke, horizontally opposed twin-cylinder
Displacement: 1085 - 1130cc
Fuel system: Bosch Motronic Fuel Injection

TRANSMISSION
Type: Five/six-speed constant mesh manual
Final drive: Shaft 

CHASSIS AND RUNNING GEAR
Frame type: Three piece with engine as stressed member
Front suspension: BMW Telelever with gas/oil single shock adjustable for preload only.
Rear suspension: BMW Paralever with gas/oil single shock adjustable for preload and rebound.
Front brakes: Twin 305mm floating discs with Brembo four-piston calipers (Plus ABS)
Rear brakes: Single 200mm disc with twin-piston caliper

DIMENSIONS AND CAPACITIES
Dry weight: 225kg
Seat height: 840/860mm
Fuel capacity: 25 litres
Wheelbase: 1499mm

PERFORMANCE
Power: 80hp at 6750rpm (1100) - 85hp at 6750pm (1150)
Torque: 9.7kg-m at 5250rpm