Bmw R75/5
BMW R75/5
Cycle World Road Test
The Wayfarer’s Choice
THERE ISN’T much question as to the intentions of BMW engineers when they designed their shaft drive 750. Produce a motorcycle at is capable of traveling great distances with a minimum of maintenance hassles. Allow for maximum rider comfort. Build a reputation for manufacturing one of the world’s finest touring motorcycles.
The latest R75/5 is precisely that, with a touch of “superbike” thrown in. Add the bonus feature of economy to the creditable performance figures and you’re faced with the prospect of riding a very desirable machine.
BeeEms don’t often give way to major change, for they are a motorcycle smelling strongly of tradition. And though tradition has its strong points, the policy can often hold back progress. Fortunately for BMW, this is not the case.
BMW is apt to improve a machine during the model year, rather than wait until new model introductions. For example, our test machine, a ’73 model, was the last of the 55-in. “short” wheelbase versions. Later models (unofficially 197314) Äot the swinging arm extended 114 in., a change BMW says is so minor most people will never notice.
The extra length is to allow the rider additional clearance between his shin and the Bing carburetors, long a sore spot on the 750cc horizontally-opposed Twin. An alternate bonus of the increased wheelbase should be a smoother ride at highway speeds, and BMW says that handling will not be affected. To identify models with the longer swinging arm at your local dealer, look for black fuel lines and flat black intake tubes to the carburetors. They were previously silver.
Other than those few items, new BeeEms are quite similar in all respects to last year’s version. And as before, the 500cc and 600cc models are available, though the 75/5 series outsells the R60/5 by nearly eight to one. Since the difference in price between the smaller models and the larger and faster 75/5 isn’t that much, most buyers are more than willing to fork over the extra cash and ride home on the top of the line. They also find that when it is time to sell, the 750 has the best resale value, though all BMWs rate high in this respect.
^ And once a buyer has decided that, indeed, it is a BMW that "e wants, choosing the model is an easier proposition than with most brands. This is due to the fact that all BMWs are identical with the exception of bore size, carburetion, and the model nameplate on the sides of the engine.
There is no worry about which model has what, because if one has it they all do. Simply decide how fast you want to motor, the health and welfare of your checkbook balance, and pick one of seven colors.
Purists stood back and examined the new styling treatment of the 1972 models when they were first introduced. Most were unhappy. The chromed fuel tank panels had them aghast, not to mention a few other new styling “touches.” But apparently the changes caught the eye of a new group of buyers, and Butler & Smith, BMW’s U.S. distributor, reports that the new design was more than successful. Sales went up. The chrome stayed. The purists frowned. But they can order the “old” style 6.2-gal. tank as an option if they’d rather.
To the average rider the BMW comes off looking strange fcndeed. After all, his cylinders aren’t sticking out the sides like *hat. But little do the neophytes know about the advantages of such an arrangement. The opposed Twin has those jugs sitting out there in all that cooling air rushing by. Overheat? Not on your life.
Too, routine servicing becomes a simple task, because plugs and carburetors are out in the open with nothing to prevent easy access. Even valve lash adjustment offers no problems. And BMW is thoughtful enough to include a tool kit that ^fcpntains everything you’d need for a roadside repair. Among ^he goodies is a tire pump, extra patches, and even a rag.
Though a BMW may look like it’s on the hefty side, don’t let the thing trick you. The R75/5 is one of the lightest 750s available, and considerably lighter than the majority of big bore machines. This has been accomplished through the extensive use of aluminum alloys and lightweight materials such as plastic.
Again, the traditionalists will probably get upset over the mere mention of the word “plastic,” but it has its good points. For example, both fenders are plastic, but you’d never know unless you gave them a tap. They are feather light, they don’t dent or rust, and they’ll probably never crack from vibration.
A duplex cradle type frame is used which features lightweight oval tubing in the main sections. The triangulation of bracing serving as the seat and rear fender support is removable, unlike most frames. Welding is on par with past BMWs, which is to say that it’s quite good. The engine/transmission unit bolts directly to the frame with no rubber mounts
cushioning whatsoever.
The 745cc flat Twin is mechanically interesting to look at. In fact passers-by with no interest whatsoever in motorcycles are likely to pause and ponder a moment.
Models from a few years back had lots of iron bits and pieces throughout, but the modern day BMW has made the switch to alloys. Now we find aluminum cylinders with a cast-in steel liner for better longevity. The main engine casting is alloy, as well. Though the unit appears as though it is on the tall side, the upper portion is comprised of an air chamber and housing for the electric starter motor.
The heavy pieces such as the forged steel crankshaft, steel connecting rods, and camshaft, are positioned down low. So in spite of the way it looks, the center of gravity is where it should be. And to help with cornering clearance, BMW raised the cylinders slightly a few years back, and that’s where they’ve been ever since. The change made it necessary to place the camshaft below the crank, rather than above, but now the cam benefits from better lubrication.
Bend down and look at the bottomside of the engine cover, and there is a large cast aluminum sump cover with cooling fins. This aids in dissipating heat from the nearly five pints of oil contained in the oiling system, which is circulated by a Eaton-type pump through a full-flow oil filter. Since plaintype bearings are used in the engine, an efficient oiling system is imperative.
A double-row chain connects the crankshaft and cam together, and features a tensioner unit to help eliminate any vibrations which may be present. Doing away with chain slack also helps somewhat in making the engine mechanically quieter, and quiet is another one of those BeeEm traditions.
This is one motorcycle that was silent before it became fashion, and now when other manufacturers are working feverishly to meet new requirements, BMW finds itself concentrating on other items. They have a right to look smug.
It’s interesting to note here that the 750 BMW has always been a strong performer, but has always been left out of the “superbike” classification. Now suddenly, many of yesterday’s ^^uper” machines are finding themselves with far more restrictive muffling and air intake tracts, due to the new laws. As a result, their drag strip times are falling off drastically, and again, BMW looks pretty smug. If anything, they’re going faster.
An automotive-type single plate dry clutch is continued on the latest models. Lever pull is light and release is positive. So positive, in fact, that power shifts produce impressive wheelies from first to second at the dragstrip. And once again, BeeEm has reduced the size of its flywheels, so the old BMW “clunk” during shifts isn’t as prevalent. With the lighter flyweels, engine rpms slow much more quickly and as a result, engine and transmission speeds synchronize just that much faster. Transmission gears were beefed up last year and no changes have been made since.
Naturally, the feature that makes the BMW stand out in the local crowd of wayfarers is shaft drive. There is no chain to lubricate, adjust, or sling oil on rider and machine. This makes for an ideal situation whether you are on a long trip or a short one. The driveshaft nestles inside the right hand swinging arm member, and connects to a hypoid gear at the rear wheel. The gear rides in an oil bath and is sealed, so the rider can virtually forget about it.
Rocking the 750 off its centerstand and climbing on feels funny if you’ve never perched yourself on a BMW. The cylinders leel as though they’ll get in the way and they give you an impression that the machine is huge. But that’s only if you’re staring down at them. And since most riders don’t stare down when they’re in motion (we hope), they forget about the fact that they’re there.
Since there is no key switch on a BMW, the ignition is turned on with a little plug-in handle that fits in a hole on the headlight nacelle. In the “down” position the ignition is on, and turning the handle left or right operates parking or running lights. This is one feature on the BMW that is annoying, and it makes theft easy since anyone with one of those plugs can start your motorcycle and ride away. A key switch is a much better way to go.
Some choke has to be fed to the Bing vaccuum-type carburetors if the engine is cold, and depressing the thumb operated button has the powerful electric starter motor
churning several revolutions before the Twin fires. Once warm, however, the engine starts with much less reluctance.
At idle the engine is quiet; blip the throttle and it stays quiet. But there is that peculiar torque reaction in the lateral plane when rpm builds. It’s very strange for someone used to a more conventional machine.
Step on the shifter pedal with your left foot and pull away; there is a shake throughout the bike at low rpm, but that disappears as revs build. And it’s not the kind of shake that gets to the rider, except for the fact that images do not focus in the rear view mirrors. Only four speeds with this one, and that’s all the BeeEm needs to do business.
Around town you can stay in first gear and not botheg anyone because of noise, but you can also lug down the 750 iir a higher gear if you don’t mind the shakes. All controls are properly spaced, but the Magura levers require some reaching with the fingers to grab hold of them firmly.
Front fork action is strange. Apply the front brake and there is 8 in. of soft compression. Yet, on certain street surfaces, the forks don’t seem to budge an inch, and the corresponding ride is harsh. The forks take the big bumps in stride, but ignore the little ones completely.
At the rear, shock action is close to perfect over any surface. They even place a handle at the bottom of each unit so the rider may change the settings without hunting for the proper tool.
On some lengthly trips, staffers began to appreciate what BMW smoothness means. Long rides and fast travel magnifies the comfort. And related handling and braking is up to the overall performance of the motorcycle. There are minor flaws and annoyances that keep the R75/5 from perfection, but overall refinement approaches excellence.
But don’t just pass judgment on a 5-mile tour around the block. Motor along for awhile. The bugs may go “splat” and the trucks may go “whoosh,” but the R75/5 doesn’t give a damn. The BMW R75/5 is one sweet ride to anywhere.
BMW R75/5
$2190
