Riding Bmw's Sensational R90s
RIDING BMW'S SENSATIONAL R90S
Fifty-Five Cubic Inches of Guaranteed Exclusivity
Bob Atkinson
BMW HAS definitely got a problem. Look at it this way. Our American image and their European image just don’t coincide. When we think of a BMW we think touring, saddlebags, a fairing maybe, and sedate performance to go with it. Sounds like a pack mule doesn’t it? And, well, pack mules just aren’t that exciting.
Close your eyes for a minute and imagine yourself in Europe. Anywhere will do, as long as it’s not too far from a major highway. Sooner or later a BMW rider will flash by. I say flash, because he won’t be going slow, picking flowers along the side of the road. He’ll be wearing either full leathers or a rain suit, and his bike will have a 5-gal. tank, narrow bars, and a skimpy luggage rack or no rack at all. Their image, quite simply put, is a combination of sport and affluency...kind of a cross between Don Juan and the Red Baron.
As for performance, Americans and Europeans are at odds again. We think in terms of the quarter-mile, and the BMW marque has never been a threat here. But the European regards performance as getting from point A to point B in the shortest possible time. A typical illustration would be gassing it up in, say, Munich, Germany, and letting off in the vicinity of Paris, France some hours later! Some of the braver pilots will make the journey hovering in the 6500 to 7000 rpm range in top cog, and that is flat hauling.
Now, for hauling even faster and with a considerable amount of style, BMW has the R90S. More cubic inches. More class. Fantastic.
Appearance wise, the R90S is like no other BMW ever made. It isn’t really a cafe racer, but it definitely leans in that direction. A rounded tail section tastefully houses the taillight and blends in with a lower seat with a better contour than found on other BMWs. The tank is a 6-odd-gallon affair which narrows appropriately at the rear, allowing the rider to become one with the machine. Then there’s a partial fairing, that adds a lot more style than protection. Still, it’s something to tuck in behind as speed increases. Completing the package are dual disc brakes (the master cylinder is located under the gas tank) and rubber sliders instead of full gaiters on the front suspension.
It’s much like any other cafe racer... until you add the paint. BMW has chosen a fogged grey with a tonal gradation that goes all the way to black. If anything, it makes the R90S look sleeker than it really is. Pretty crafty, those Germans.
Appearance isn’t the only ingredient necessary to change an image. Performance weighs heavily, and BMW has done something about that, too. When you straddle an R90S, the first thing that catches your eye is a new instrument group. There is now a separate tachometer and speedometer. Just above these are two smaller gauges—a clock and an ammeter. It’s kind of like the dash on a small GT car. Push the electric start button next to the right hand grip and the 900 springs instantly to life.
Surprisingly, the 900cc S idles smoothly, in spite of its slightly more radical camshaft and larger carburetors. Both the 750 and the new 900 T have constant velocity 32mm Bings. The S comes with 38mm slide type Dellorto PHMs. When you let out the clutch for a normal take off, the S feels about like a standard 750. There’s a little less torque right off the bottom than the 900 T has. But, get the S engine up to around 4000 and punch it and there is considerably more steam, right up to the 7000 rpm limit.
I got a chance to run the S hard on BMWs test track outside of Munich and there, BeeEms finest is a convincing^ stable performer. Out of any of the numerous tight turns, the S accelerates smartly, thanks to accelerator pumps in the new carburetors. For the most part the engine will respond instantly, but the rider’s task is hampered by a throttle that is not quick enough for precise control.
There’s a left at the end of the front straight that’s a true test for brakes. On the S, two fingers and moderate pull will let you squeal the front tire. Feather in the rear for more control and the 474-lb. machine halts quickly, every time.
You don’t really pitch a BeeEm into a turn, rather, you lean it over with considerable body english, especially if it’s a near 90-degree turn at the end of a straight. If you persist (I did), the side stand will ground in turns like this, but nothing comes of it as the stand is too flexible to lift the rear wheel off the pavement.
Next comes a downhill hairpin right. You touch the brakes, apply body english (lots this time) to shift the bike over center and gas it down to a hairpin left. In most of these corners I was banked over far enough to grind the bottom of the foot pegs away. Until I got a little carried away and lifted the rear wheel off in one turn, the fact that I was dragging didn’t enter my mind. The R90S is that stable.
The remainder of the handling course is a series of sweepers and a jump that can be negotiated in a variety of combinations. You’ve got to watch it a bit over the jump. If you come down with the power on, the BeeEm gets a little squirrelly. In any of the sweepers, it was stable and steered well, right up to the point the rear end began to drift.
As for grinding holes in valve covers from dragging them in turns, don’t worry about it. It just doesn’t happen very often, and you have to be leaned way over when it does.
There wasn’t really room on the handling track to get into fifth (all 1974 BeeEms are five-speeds), but I did change a lot of gears, and happily, the famed BMW clunk is not nearly as pronounced as it has been in the past. This isn’t the result of a new cush-drive setup. Rather, it is a byproduct of closer gear spacing which allows engine and transmission speeds to synchronize a little faster.
Technically, the R90S is similar to the rest of the BeeEm line. The engine is an overhead valve, opposed Twin with the camshaft positioned below the forged steel crankshaft. The cam is driven by a double-row chain with a tensioner unit, which does away with chain slack. The crank is similar to the 750 (both have the same stroke), but it is balanced differently to work with the larger pistons in the 900. The barrels, naturally, feature a bigger bore, but are still made from aluminum alloy with a cast-in steel liner.
Compression is up to 9.5:1 from 9.0, and as mentioned earlier, there are larger carburetors with accelerator pumps. All together, the setup is good for 67 bhp (DIN) or 77 bhp (SAE) at 7000 rpm.
It’s not the most powerful motorcycle on the road, but it’ll go fast enough to scare anybody. And it will do it mile after mile after mile.
As for price...we don’t know yet, but it will be expensive. Class, though, has never been cheap! £§]
BMW
R90S
