Bmw R100rs
BMW R100RS
Cycle World Road Test
The speedometer needle is a bit wavery, bouncing back and forth between 115 and 120 mph, there is a strong force of wind against the helmet and the engine is a muted hum below. On the right is the Pacific Ocean, on the left, rolling hills and cattle. The motorcycle is in a rhythm, happy and comfortable at these speeds. There is a feeling of stability, the suspension is firm enough to give complete control, yet supple enough to soak up undulations and ripples that pass beneath the tires in nanoseconds.
Ignoring the speed and rush of wind, the quartz clock’s second hand ticks away. The tach needle also wavers like the speedometer, near the redline limit of 7000 rpm. But the uncanny thing about it all is that the only real rush of wind is against your helmet. The machine is as comfortable and secure as if it were running along at the federally posted 55.
No. This is not an ordinary motorcycle. It is the latest, most posh and most flamboyant BMW ever produced. With its highly stylized, full body enclosure that many will refer to as a fairing, it is as unlikely a BMW as can be imagined, and yet, it is unmistakably a BMW.
One could ask how such a model ever came about. After all, the BMW R90S was one of the most highly regarded motorcycles to ever roll down the pike. But in the game of one-upsmanship, BMW perhaps felt that it was once again their turn to answer the call of Limited Edition GL1000s, LTD Kawasakis, shaft-drive Yamahas and the latest in four-stroke Suzukis. Perhaps. And then again, maybe they didn’t care about all the others, maybe they just wanted to one-up themselves. There can be no question that they have done precisely that.
For 1977 BMW offers a number of models, starting with the R60/7 and running through the R75/7, the R100/7, an RIOOS and to the top machine of the line, the R100RS. Both the S and RS are the sport machines of the small group, but the RS is definitely the more extravagant of the two. Introducing new features that are exclusive to itself, the RS also shows off 1977 BMW innovations included on all models.
Let’s ignore the billboard proclamation RS jazz for a bit and get down to the BMW basics. Major changes take place infrequently with Beemers, but there are little things happening constantly. It is common to see mid-year or quarter-year modifications pop into sight without prior warning, and naturally these changes make their way into the dealer’s showroom as time passes. A good example for mid-year changes is 1976. Several were made and are carried through to the 1977 model line.
Many of us wonder how in this day and age an opposed Twin can survive among the latest in sophisticated powerplants rolling off Japanese motorcycle assembly lines. And that is a ponderable thing. How does the BMW Twin remain successful against the multitude of dohc Fours and refined Triples et al? Some of it can be attributed to owner loyalty, some to the fact that no one else builds anything like it. To some, different is good. Yes, the engine has a reputation for reliability and those interested in mechanicals know the engine is less complex and easier to work on than most of the Japanese exotica. Perhaps this is how the opposed BMW Twin survives. It is alive, well and healthier than ever.
The R100/7, RIOOS and R100RS now feature 980 cc of displacement, up from the 898-cc engine of last year. This came about through the increase of bore size from 90 mm to 94 mm, but newly designed pistons are said to weigh the same as the former, smaller ones. Because the power output of the new, larger engine is greater, BMW engineers haven’t overlooked areas that may be stressed because of the additional power.
SUSPENSION DYNO TEST
FRONT FORKS
REAR SHOCKS
Description: BMW fork, HD315 oil Fork travel, in.: 7.2 Engagement, in.: 6.25 Spring rate, lb./in.: 20/36 progressive Compression damping force, ib.: 12 Rebound damping force, ib.: 19 Static seal friction, ib.: 11
Remarks: BMW front suspension is commensurate with the bike’s overall character, initial damping and spring rate give a plush ride, while progressively stiffer damping toward the end of compression prevents bottoming. More enthusiastic riders or dedicated tourers may wish to use heavier fork oil for added control; no other modifications should be necessary.
Taste performed at Number One Products
Description: Boge shock, gas/oil mix, non-rebuildable. Shock travel, in.: 3.9 Wheel travel, in.: 5.0 Spring rate, lb./in.: 95/225 progressive Compression damping force, Ib.: 8 Rebound damping force, Ib.: 82
Remarks: The stock Boge shock should be adequate for most riding situations. The traditional lever makes preload adjustment extremely easy, and is usually sufficient to compensate for the additional weight of a passenger or equipment. Because damping requirements are critical on shaft-drive bikes, selection of a performance-type aftermarket shock can be difficult. If you can get a pair, the factory highperformance Boge shocks would be the ideal replacement.
Actually they began looking into this during last year’s production run, and began beefing up the crankcases, particularly the front main bearing area. This gives some added insurance along with increased power impulses, and they carry the strengthening into the transmission case as well.
One of our areas of criticism in the past has been with the transmission. It seems year by year there is less clunk and more snick while going through the gears; this 1977 model is no exception. But it pays to remember that BMWs tend to become much smoother as the miles add up. This is especially true in the case of the gearbox. As our new RIOORS worked its odometer we worked the transmission, and the shifts got easier and required less lever pressure and neutral became available when we wanted it, stopped or moving.
Shorter, thicker cylinder fins are new, as are the cylinder heads finished in black, with raised areas buffed to a high gloss. The new heads are attractive and give the engine a fresh look. O-rings also replace the base gaskets for supposedly better sealing. Pushrods made from alloy were phased in during 1976 and continue on 1977 750s and 1000s. They tend to reduce valve train noise.
Other internal changes include a heavier-duty clutch disc and new cam followers. The starter motor also has a new ratio to make it more powerful and a bigger battery is included to give the starter motor the juice it needs.
Part of the reason the new machine feels so stable at all speeds, especially higher ones, is found in the frame. By adding a bit more gusseting to the swing arm and one simple cross brace between the two front frame downtubes, the chassis is more rigid and takes on a whole new personality.
Suspension plays a hand in this as well. If the forks feel different to someone who is used to BMWs, that’s because they are. While we’ve applauded the plushness of the long-travel BeeEm forks, we’ve found ourselves cussing them when riding hard. The old-style forks allowed the bike to dive heavily during braking, using up precious ground clearance in the process. There is no more of that. Rather, BMW engineers re-valved the forks to allow a softer action in the middle of the stroke and a gradually stiffer action as the sliders move into the cast legs.
No change has been made to the rear shocks, which are manufactured in Europe by Boge. Springs are three-way adjustable and rear suspension has five inches of travel, which goes nicely with the sevenplus inches of travel up front. One has to look long and hard to find a motorcycle that suspends like the BMW for all-around riding conditions and riding styles.
When one is riding a machine that will make tracks down the highway at nearly 120 mph there is a high degree of interest in braking ability. Here one needn’t worry. The RS stoppers do the job, easily and precisely. Pre-1976 R90S braking bothered us only because the dual front discs required so much hand pressure at the lever. A change in the caliper cylinders and master cylinder ended the annoyance and the latest S and RS benefit from the switch. Holes in the discs save a slight amount of weight but more important, they allow the escape of water during wet weather braking, making the discs more efficient and effective. Earlier units made a funny whirring noise when the brakes were applied. We suspect something has been altered because the latest discs are quiet. And don’t believe the bit about the discs being treated with cadium plating to prevent rusting. The holes and outer edge of the test machine’s discs went rusty on us, and the problem also surfaced on a formerly owned staffer’s R90S, annoying him.
BMW
R100RS
$4595
The rear brake is a standard drum arrangement and though not quite in vogue on a $5000 eye catcher, it does a perfectly adequate job. If the RS happens to be equipped with the $400 optional cast alloy wheels, air scoops help direct cooling air to the rear brake hub unit.
Most BMWs we see these days are coming through with Continental tires and the RS has them. The H-rated rubber is a definite plus on such a machine. They stick well and do not give the rider false confidence. Reliable sources tell us the Continentals keep their tread for a long time as well, an important consideration on a bike designed to rack up miles like a Peterbilt Semi.
BMWs have become almost synonymous with long distance travel and one can’t help but wonder how the RS fits this category. In theory, the RS has all the accouterments to make it the tourer of tourers until you examine more deeply. That fairing does look like the answer and in many ways it is. But there is no storage space and the unit’s design necessitates handlebars that may not please many who are bent (gasp) on running 500-600 miles in a day.
“Well,” you say. “Who said anything about this machine being a touring bike? Anyone can see that it’s a pure sport machine.” And that’s what is so confusing about the RS. Just whose bike is it, anyway? The tourers won’t like the IV2 person seat and the lack of space for stowage; the sporting group will probably find the fairing a bit too big. It’ll probably cramp their style. The RS has to find its own niche. BMW must think there are more than enough potential owners out there with the capital and desire to own the RS strictly on terms of its own uniqueness. We are inclined to agree.
When BMW says their fairing is more than just another fairing, they’re right. The unit is integrated, designed to be a part of the motorcycle rather than something hung on for the ride. Wind tunnel testing played a large part in the design and that fact makes itself known immediately when one heads down the road. According to the folks who produce the machine, the new fairing (when compared to the lA fairing on the RIOOS) reduces side wind response by 60 percent, front wheel lift 17.4 percent and wind resistance 5.4 percent. By all indications it does all that and then some.
It doesn’t seem to matter what speed the bike is traveling, very little buffeting or wind force reaches the rider, except off the top of the windscreen where it barks at his helmet. This isn’t disconcerting and probably the only reason it manifests itself is because of the lack of wind on the rider anywhere else. If one studies the fairing from one side there is a lot that meets the eye and all of it can be appreciated. Styling is bold but it is easy to see that what is there isn’t just for looks. The shape directs wind forces away from the rider and at the same time puts downward forces on the motorcycle. The stability exhibited by the RS at speed demonstrates the fact beautifully.
The unit is integral but that doesn’t mean it prevents access to important servicing operations or maintenance. The upper half or top section doesn’t have to come off for any normal reason, but if it ever does, the wiring is quick disconnect. The dash area and controls come across as very unmotorcycle, more like the command center for a small space module. The quartz clock, ignition key-switch and voltmeter are part of the dash unit, which is in turn part of the main fairing portion.
Around front, things are even more tidy. Headlight (a better one won’t be found except on another BMW) parking light (how many motorcycles have a parking light?) and turn indicators are faired into the front surface of the fairing. Actually, the headlight sits behind a clear cover that has five orange stripes running horizontally across its surface. The stripes look a lot like the ones found in automobile windows that are equipped with electric defoggers. They aren’t defoggers on the BMW; perhaps only a styling embellishment.
The rider is not only protected from the wind, but is kept drier in wet weather. Water has a tendency to find its way through openings in fairings where they clear forks tubes and the like, but the RS uses rubber seals in the shape of round cups that encircle the fork tubes so water can’t come gurgling up the tube and into the rider’s lap.
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Since no cooling air reaches the rider because of the fairing enclosure, warm weather riding can get too warm. A good amount of hot air radiating off the cylinders comes right back on the rider’s legs, but it is simple enough to unfasten the retaining screws which hold the lower panels in place, drop the header pipes and remove the panels. To get to the front cover of the engine for point service and timing, the fairing grille removes quickly by undoing eight screws. Despite the elaborate look of the unit, it weighs just a hair over 20 lb., so the weight penalty is minimal.
Hand switches are like last year’s with one exception. A thumb tab on the turn signal switch makes it far easier to reach with the right hand. And yes, the right side, up-down mode can become automatic in a short amount of time, believe it or not. But we can’t say that for the bars.
Here is an area where the fairing’s design dictated the size, angle and shape of the bars, and they’re not right. Unlike the bars on the R100S (which we think are just about perfect) these angle the wrists unnaturally and make the ride tiring after about a 50-mile distance. Because of the fairing, an easy switch or modification isn’t possible. We’ll have to leave it up to BMW to make a change; we hope it comes quickly.
The RS buyer can choose between two different seats, the one pictured in the test here, a VÁ capacity model, or the more practical and comfortable unit from the RIOOS, a true two seater. Either way, underneath you’ll find the BMW features we’ve come to know and love. There’s that wonderful tool kit and shop cloth in a removable tray, a document holder and a tail section compartment. There’s even a tire pump and tire repair kit. Nice.
The RIOORS comes painted in a muted silver tone, presumably a reminder of German racing colors. The finish is acceptable, only. And the pinstriping on our test machine was not up to the quality level one expects from BMW. More odd still, the wheel rims were striped with blue and the front brake calipers are anodized in the same distracting shade, for a paint scheme that’s, well, controversial.
Once the rider settles into the crouch necessitated by bar and footpeg location, a few items will be noticed besides ones we’ve previously mentioned. Footpeg rubber is new and the more heavily covered pegs seem to vibrate less and are more comfortable on the arches of the feet. Handgrips are by Magura, not nearly as bad as some but not the most comfortable either.
The twist grip connects up to new carburetors. In the past the hot R90S has used the Dellorto pumper units; this time around a switch has been made to Bing V 94 constant vacuum 40-mm carbs, mostly because Bings are easier to get.
Mirrors on the RS are good, but have to be adjusted just so to take advantage of their wide-angle capacity. They come in especially handy when the speed limit is being tested and a clear view of what’s behind is important.
When RSing it through the mountains the new BMW stability really shines through. The only worry will be the usual BMW touchdown points, the side stand on the left and the brake pedal on the right. Run it harder and you’ll get the cylinder heads and perhaps scare yourself in the process, but you’ll still be within the tire’s limits.
No matter where the new RS fits in the marketplace and who will go for its unusual appeal, one fact remains. The only thing that will get more attention than the RS itself will be the piercing double-tone horns. One toot will have the car people searching for the Semi that’s about to get them. Imagine their surprise when the RS glides smoothly past. |§]
