Four stroke,
two cylinder horizontally opposed Boxer, pushrod operated 2 valves per cylinder.
Capacity
494 cc / 30.1 cu in.
Bore x Stroke
68 x 68 mm
Compression Ratio
6.8:1
Cooling System
Air cooled
Induction
2 x Bing
1/24/45 - 1/24/46 carburetors
Ignition
Magneto ignition
Starting
Kick
Clutch
Single plate saucer spring, dry
Max Power
19.4 kW / 26 hp @ 5800 rpm
Transmission
4 Speed
Final
Drive
Shaft
Gear Ratio
1st 5.33 / 2nd 3.02 / 3rd 2.04 / 4th 1.54:1
Frame
Double loop steel tubular frame
Front Suspension
Telescopic fork
Rear Suspension
Long swing arm with
suspension units and oil pressure shock absorbers
Front Brakes
∅200mm Drum, duplex full hub
Rear Brakes
∅200mm Drum, simplex full hub
Front Tyre
3.50 -18"
Rear Tyre
4.00 -18"
Wet-Weight
195 kg / 429 lbs
Fuel Capacity
17 liters
/ 4.49 US gal
You waft across the sunny countryside with just a
rustle of cleft air and, maybe, a faint whine from the tyres. Footrests,
handlebar, kneegrips and luxurious seat fit you as unobtrusively as a Savile Row
suit. Smooth controls lie close to your fingers and toes. Every muscle is
relaxed as you lean imperceptibly on the wind.
As the road veers this way and that your bike
curves round on invisible rails. You twist the grip. Silkily, almost
apologetically, your bus flows up the speed scale. Caress the brakes and a giant
magnet holds you back. When you want to overtake you choose between a horn that
can really be heard and a button that flashes the 35-watt main beam. And there
are grip-tip winkers.
Night falls and your lights flood the road with
brilliant illumination. Halt and you have to lower your head to hear the slow
chuff-chuff of the tickover.
What's this—a pedal for starting? Well, yes; but
so gentle a prod is called for that a schoolgirl could give it. And the response
is certain.
This is a bike for riding, not tinkering with.
Just about all you do is tank-up every 200 miles. Cleaning is feather-duster
stuff.
Ah, sweet dream. What a pity to wake to reality.
But there is no need if you ride a BMW twin. All these joys are yours on an R50
five-hundred. And, since the compression ratio is low, they are yours on
regular-grade petrol.
The R50 is the woolliest of the BMW twins.
(Riders who want an out-and-out sports performance may prefer the R50S or R69S.)
For all that the top speed of 90 mph was timed when the test machine was barely
run-in.
On first acquaintance, acceleration seems
gentle—a deception due partly to the machine's uncanny smoothness and quietness
and partly to the progressive-rate twistgrip. This has a slow action at small
openings, blending into a quick action at large openings.
In dense traffic the slow action is a boon. And
when it's vivid acceleration you want, you have only to take a big-enough
handful of grip and let the revs mount freely through the gears. Speedwise, the
best results are obtained by holding each gear until the speedometer needle
reaches the blue mark On the dial that corresponds to peak-power revs of 5,800
rpm. With this technique, third proved to be a very useful gear, especially when
a passenger was carried.
Initially, if the engine was allowed to slog very
hard in top, there was slight harshness (by BMW standards!) around 56 mph. This
was completely eliminated by slightly tightening the rubber mounting at the top
of the engine.
Once top gear was -- notched the R50 would cruise
at any speed between 70 mph, against a stiff head wind, and 80 mph in fair
conditions.
Of course, on a machine of the R50's calibre the
speedometer was true. It was also very smooth in action.
The BMW kick-starter is on the left side of the
machine and moves transversely. Yet it is quite easy to operate, either with the
right foot before mounting or the left foot once astride.
For cold starting the choke on the air filter has
to be closed. It can be part-opened as soon as the engine fires and is easily
reached from the saddle for full opening.
When the throttle cables had settled down, it
proved worth while to match their adjustments precisely. This eliminated a
slight rock on idling.
The clutch is smooth in take-up, though quick
because it runs at engine speed and the flywheel is heavy. This layout has never
given the slick, knife-into-butter gear changes of the best conventional layouts
but, provided the control movements are properly synchronized, it is not
difficult to make reasonably fast and quiet changes—especially now the ratios
are medium-close rather than uncommonly wide as they were some years ago.
RELENTLESS
In spite of the raising of the lower ratios, the
R50 took a 1 in 3 restart in its stride.
Except that the first application of the front
brake on a humid day called for a delicate touch if the result was not to be
fierce, the brakes proved superb. Smooth and immensely powerful, they pinned the
R50 down relentlessly regardless of load or speed.
The progressive-rate springing has the low-speed
firmness associated with high-speed stability. Yet there was a remotefeel about
shocks that got through —as if they were being funneled off to nearby vehicles.
Pre-loading the rear springs for pillion work is a matter of seconds and calls
for no tools. You just tweak two levers.
At first the steering had a disconcerting
low-speed roll. But that disappeared immediately initial over-tightening of the
head bearings was eased. From then on, straight-ahead stability was above
average, yet the machine responded precisely to banking.
Nor was there any practical limit to the degree
of banking that could be used. For, at 21 in, the R50 is unusually slim across
the footrests.
CHILD'S PLAY
In dream-bus reveries, of course, the sun always
shines. But rain bothers the BMW rider less than most. Waterproofing is
extremely thorough, mud-guarding efficient and the cylinders shield the feet.
Maintenance is child's play, for the few routine
adjustments are very accessible, as are the oil-level plugs.
What of the debit side? Well, let's be finicky.
The R50 is no lightweight and a determined effort is needed to put it on the
centre stand. Maybe the twist-grip and front-brake lever are a shade heavier to
operate than some. But you can't tell the difference at the end of a day' in the
saddle.
No, the R50 stands out from the ruck as a
superb tourer for the connoisseur—a pride and joy to own. Its impeccable manners
inevitably keep the rider always on his best and most courteous behaviour.