Norton Atlas 750
Norton Atlas 750
parallel twin cylinder, push rod, 2
valves per cylinder.
745 cc / 45.5 cu in
Bore x Stroke
73 x 89 mm
2 x Ø30mm Amal concentric carburetors
Lucas big-capacitor electric system
43.3 kW / 58 hp @ 6800 rpm
Dual shocks, 5-way adjustable
Ø203 mm Drum
Ø178 mm Drum
13.5 L / 3.6 US gal
Throw a leg over either one of these big Nortons
and you'll know right quick you've got yourself a very authorative riding iron.
That is, when and if she fires up, there's just about no production bike made
that will beat you to wherever you choose to go, be it the end of the block or
the end of the continent. And all the time you're whistling in that direction,
you can think about (if just holding on doesn't give you enough to think about)
the sixty or so years of high and glorious motorcycle achievement borne by that
much-traded but not overly tarnished marque Norton.
And if thinking about tradition isn't meaty
enough, you've got a substantial bit of it hanging out there under your gas tank
in full public view. Where else today can you find a motorcycle with all those
exposed nuts and bolts and pipes and rods and wires and cables and clamps and
tubes and enclosures and tanks and electrical devices—all sort of crammed in
between the front down tubes and rear wheel? A classic that's still in
production, with a classic indifference to modern tidiness, a classic respect
for bhp, and a classic mastery of that timeless virtue—roadholding.
You won't buy a Norton Atlas for surprises; the
blessings and less of this fabled charger are well-catalogued in the literature
and in the countless utterances mouthed in the back rooms of motorcycle shops.
If it's novelty you're after, try today's companion piece, the P-11 Scrambler,
built with a brand-new Metisse-type frame and lots of other bits that have been
around awhile, lashed together into a complicated but quite workable package.
Nineteen sixty-seven is the year of sale. You should be a little taller and a
little stronger—and maybe have a little bit more confidence and a little bit
more patience—than your everyday buzz-bomb rider, but then you will find a very
satisfying ride in either of these hefty 750s.
The Atlas and P-11 have much in common, like the
engine, gearbox, electrics and instrumentation, but there are minor differences
even in these. On our two test bikes, for example, the Atlas was fitted with
standard Amal mono-bloc 30mm carburetors, while the P-11 featured the new Amal
concentric-floatbowl variety. And the P-11 had that clever new Lucas
big-capacitor electric system, which , we were told, will soon find its way onto
production Atlases too.
The engine is the same one that began its life
years ago as a five-hundred, was stroked to 600, bored to 650, and stroked again
to 750. For years everybody has been saying of the Norton twin, "That's really
only a 500 carrying oversize pots and carburetors." Well, you might make
something out of that, for once there was a rash of lower-end failures. But in
fact the Norton lower-end is now very substantial, and now there's a
double-volume oil pump to fix the real source of trouble. The cases are solid
enough, the bearings big enough, the materials strong enough, to take all fifty
thumping horses those 750cc deliver.
Engine layout is conventionally British: with a
360-degree crank, cylinders parallel, pistons moving up and down together, but
firing alternately. Gears drive the single camshaft, which in turn drives its
followers and pushrods to the rocker arms and valves. At the left (drive) end of
the crank is mounted the 12 volt alternator and a sprocket which carries the
chain primary drive to the clutch housing on the gearbox. On the right end is
the timing gear, oil pump, and tachometer drive.
Unlike most modern bikes, the Norton big twins
don't have the engine and gearbox combined in a single unit. Instead the compact
(though heavy) four-speed gearbox sits aft of the power-plant, bolted in place
to a substructure of mounting plates. The gears in this well-developed package
are robust and gearchanging is quick and smooth. The clutch, too,' is more than
strong enough to handle the power driven through it. Probably not because this
is the last of the old-time separate gearboxes, but because it is a very good
one, this unit is invariably adapted by specials builders for street and
competition. It has even found its way into automobile layouts.
In discussing the electrics, we shall concentrate
on the P-11, since its arrangement is destined for the Atlas as well. Our test
Atlas had the older Lucas magneto-and coil ignition system, which you can quite
simply convert to the new system with some rewiring and adding the capacitor.
The scrambler has the same alternator and a battery, though now the latter can
be removed in the interests of weight reduction. A big capacitor, wired in
parallel to the battery, acts instantaneously like a battery itself by storing
charge. When the breaker points open, it dumps the charge as current through the
primary windings of the HT coil. Result: a very hot, uniform spark, virtually
independent of engine rpm, and considerably less sensitive to precise
coordination with the alternator output pulses.
In practice this means you get much easier
starting, your machine will run even if the battery goes dead, and because the
capacitor smooths out voltage ripple from the alternator, the electrical
components in the system will last longer. Altogether very useful. Of our two
test bikes, the P-11 was by far the easier to get started.
Instrumentation on both bikes is the usual set-up
on British big twins: a Smith's speedometer-odometer and a separate mechanical
tachometer, an ammeter, and a high-beam indicator. Headlight and tailight are
12-volt Lucas units that put out plenty of light. On the P-11, lighting is
quickly detachable, and the large Atlas-type tail-light will be replaced by one
smaller and more stylish.
Despite many features in common, the big Norton
750s are really quite different beasts. The Atlas is an all-out road bike, made
for high-speed touring or just dashing about wildly on those winding,
back-country roads. The miracle of the Atlas is its celebrated "featherbed"
frame, a frame that has served as a model and point of departure for frame
designers for over 30 years. What makes this frame work so beautifully is still
something of a mystery, but in combination with Norton's roadholder forks, it
provides about the best handling available from a motorcycle today.
That big, harsh, torquey 750 engine, when laced
into the featherbed, becomes as civilized as it ever will. As far as the rider
is concerned, its jarring vibrations disappear, but not its tigerish
acceleration. The featherbed frame, a double-loop that on inspection holds no
surprises, was once considered a model for lightness. Today it's about average
weight, but it does what it's meant for. Riding the Atlas is an experience that
cannot be understood short of the deed itself. You can whistle along at
tremendous speeds over the most primitive road surfaces and around the most
treacherous corners without the slightest twinge of anxiety. At very slow
speeds, there is a trace of over-steer, a feeling that those front forks want to
pick their own line. But on the open road you can drive as hard as your courage
will allow and feel confident that this bike will not only draw out the best of
your talents, but cover most of your mistakes.
Norton's roadholder forks were the first to
really embody the "combination" for good tracking. Damping, spring rates, rake,
trail, and travel—all blend uniquely ad effectively. These forks are often
adapted to other motorcycles, where they usually work well, but they are best
with the Norton frame. The front brake is a large-diameter, full-width stopper
well-suited to Atlas performance. Like the rear unit, it is actuated by a single
cam, but again the combination of size, designing and materials is right for the
When, some years back, Norton decided to use
their 750cc powerplant in a scrmbler, they had to look for a new frame. Besides
being too heavy, the "featherbed" just wasn't meant for the dirt. So Norton
elected to bolt their engine in the Matchless scrambler frame, originally built
for the Matchless 500cc single. This worked out reasonably well, providing a
bike for the dirt-bangers with plenty of power at the rear wheel. But the
combination was almost overpowered, and it was heavy and bit unweildy. Also, the
Berliner Motor Corp., U.S. distributors for Norton and Matchless, found that
many American riders were taking off the knobbies and fitting street tires in an
attempt to realize an on-the-road/off-the road bike.
Ruminating on this phenomenon brought the idea of
the P-11, a lighter-still scrambler with street potential. Or, a street-bike
that will go like blazes in the dirt. It's major difference is the frame, a
structure that resembles in a way the "Metisse" frames created in recent years
by Britain's Rickman brothers. Wedded to Matchless forks and other running gear,
it produces a ride quite unlike any scrambler we had ridden before, but it was a
ride that quickly became workable. Curiously, our "scram= bler" was fitted out
with Dunlop K-70 street tires, and undoubtedly most of the units sold will ride
out their lives on pavement.
The P-11 is a very impressive machine to look at,
with its high-swept exhaust pipes, wide-reinforced handlebars and all that. It
differs from the older Norton scrambler (still available) mainly in its new
frame, its concentric Amals, its high pipes and its funny turned-down Matchless
brake drums. Cursory inspection indicates that both models use the same forged
steering head and bolt-on bashplate. Future P-11 s, we were told, will have
aluminum hub covers, a chain guard, and different color options on tanks and
panels, and possibly a dual seat.
So how does it go? Well, it's geared a bit higher
than the Atlas and in fine tune on pavement it goes like lightning (so to
speak). A very tall bike, it will lean into turns at staggering angles, pull up
short and manouver about like a bike half it's size. If no one had told us it
was a scrambler, we would swear it was an all-out street bike with a drag-strip
in its future. And unlike our test Atlas, it was fitted with a dual fuel-tap
arrangement that lets through enough gas for those hungry 30mm carburetors.
Stock gearing is nearly perfect for the road, and the engine will just pull its
6500 maximum in top gear. That, friends, is 113 mph.
The dirt offered altogether different problems to
this torquey "scrambler." Using the K-70s, we found that (much like the older
scrambler) the P-11 must be steered with the throttle. You twist on the wick
until you've spun into the line you're looking for. The rear end under power
tended to twitch back and forth like a turned on tadpole—not that you'd lose it:
stability even over jumps was very good. The front end wouldn't hold well in the
dirt, but this could probably be cured with knobbies. Fork rake looks ideal for
fast cross-country scrambling. And the seat and bars, awkWard at speed on
pavement, are just right in the dirt, allowing for quick peg-standing and weight
shifting. Ground clearance is good and the bike's weight—well, it's still too
heavy for all but a very robust or very experienced rider. Braking is not quite
adequate on pavement and too powerful (snatchy) on dirt, but we assume anyone
headed for out-and-out dirt competition would do a substantial amount of prior
As a package, the P-11 strikes us as a very
perplexing bundle of contradictions. Like the Atlas it features a superb
frame-and-suspension combination with a very solid engine. But like the Atlas
there are minor and annoying faults that betray careless quality control at, the
factory level. Castings are rough, joints ooze, tubes leak, fastenings come
loose with alarming frequency. We like to think a high-performance bike should
be tight as the proverbial drum. The answer for buyers, unless their models come
through better done that ours, is to go over their bikes from nose to tail,
fixing and finishing everything to the high professional standards these big
You might wonder why a company with
a fine-handling bike like the Atlas would bother to create another fine-handling
bike like the P-11. That must be the world of merchandising, and the P-11 does
offer off-the-road adaptability which the featherbed frame can't negotiate. They
may be a bit heavy and their packaging more than a little old-fashioned, but
these fabulous Nortons will still give you rides as exhilarating as any you're
likely to experience