Air cooled, four stroke, parallel twin cylinder, SOHC, 2
valve per cylinder.
Bore x Stroke
80 x 74 mm
2x Dell'Orto PHF carbs.
61 hp 44.5 KW @ 7500 rpm
5 Speed / chain
2X 230mm drum
SF First Version (1970)
This original SF series was built from frame number 3808 onwards. The coding
SF (standing for 'Super Freno', or 'super brake') referred to the adoption of
entirely new drum brakes designed by the company's founder, Dr Francesco
Laverda. (The rest of the design was carried out by Luciano Zen and other
members of Laverda's engineering team.) The majority of the production run
featured a cylinder barrel-high exhaust connector tube connecting the two header
pipes. Except for the brakes, this first SF was virtually identical to the 750S
that proceeded it.
SF Second Version (1971)
For the 1971 model year, the SF underwent a number of changes. The most
important of these was a change from British Smiths to Japanese Nippon-Denso
instruments, a new fuel tank (which no longer had the rubbers for the rider's
knees), and an optional lockable storage box incorporated in the racing-type
The name Laverda is fairly new to the American
motorcycling public, but the bike has been around for some time, having first
been imported to this country as the "American Eagle." The Santa Ana,
Calif.-based American Eagle firm is now defunct, but the Laverda is alive and
well. Edison Dye, the West Coast importer of Husqvarna, is taking over where the
Eagle left off. The flow of bikes and parts from Italy won't be of
Japanese-style volume, but the situation is certainly better than no bikes at
all. The Laverda is sound, and deserves an American audience.
Could anyone; have imagined three years ago that
the Laverda (American Eagle 750S Sport) would be the basis for one of 1971's
most successful production road-racers? We'd have been inclined to say not.
However, the sports-minded Italians at the
Laverda factory modified their 750, fettled it as a 750cc. production racer and
walked away with 1st, 2nd and 3rd places at Barcelona, Spain; 1st, 3rd and 4th
places at Zandvoort, Holland, and 2nd, 4th and 5th places at Le Mans, France.
These three races were all over 12 hours in duration and the factory-`team of
three' machines finished each one with a high placing. Obviously wasn't just
luck, and the 750 SF lives right up to them, reputation gained by its production
road racer brother.
There are two versions available. The GT, a
milder version of the SF, features less compression, milder cams, no exhaust
balance pipe, a dual seat, and small detail differences including a slightly
less rigid frame and less steering trail to make it more suitable for in town
riding and medium speed touring.
The 750 SF, on the other hand, is a sporting
man's motorcycle. Low, narrow (26-in.) handlebars, a headlight fairing and a
short racing-type seat set the scene and rather rear mounted footrests make the
rider feel like he's on a road racer. Quite heavy at 507 lb. with half-tank of
fuel, the 750 SF is fairly clumsy at ultra-low speeds but loses this feeling at
speeds above 20 mph or so and begins to feel like it should... a sports/roadster
with a racing heritage.
Much of the Laverda's handling comes from
race-proven frame and steering geometry. A double cradle-type frame with a
multitude of top tubes supports the engine at the cylinder head with four
mountings and the rear of the crankcase/transmission casting with an additional
four mountings. There are no front down tubes; the engine just sort of hangs in
there like the Honda Hawk series motorcycles of the mid-60s. If the frame tubes
and engine unit are suitably strong, there is no reason to install front tubes
Utilizing large tubes with sufficient
triangulation, the Laverda's frame is strong enough to resist flexing from side
loads imposed by vigorous cornering as well as those experienced while riding at
speed over bumpy roads. Construction detail on the frame is good: welds are
smooth, paintwork is smoothly applied and the whole package "looks" right, even
though the frame is on the heavy side.
Braking, too, has benefited from Laverda's road
racing ventures. Slightly over nine inches in diameter, both brakes feature
double leading shoes using two brake arms which pull toward each other, instead
of a rod between the arms which requires critical adjustment to work properly.
Cool air is admitted to the front brake by a ribbed scoop cast into the brake
backing plate, and a fan-type arrangement is employed on the rear wheel. After
circulating around inside the brake drums and cooling them and the brake shoes,
hot air is expelled through slots in the central portion of the hubs.
A brake swept area figure of 67 sq. in. for a
machine weighing over 500 lb. might not sound too impressive, but the brakes are
so well designed and executed that they match the machine's performance with no
trouble. In fact, the rear brake must be applied with caution during heavy
deceleration or it will lock up. This is caused by the tremendous mechanical
advantage afforded by the long brake pedal assembly. It's rather like having a
power assisted rear brake.
The Ceriani people have the reputation of
producing some of the finest suspension units for motorcycles in the world and
those fitted to both the front and rear of the 750 SF are no exception. The
front forks are slightly stiff, fitting the nature of the machine, but have more
than adequate travel and rebound damping characteristics for fast riding. A nice
touch is the pair of aluminum alloy triple-clamps and the aluminum alloy
steering damper knob. So precise and stable is the steering that we didn't
bother using the damper at all. Also slightly stiffly sprung, the rear
suspension units have more positive damping than other Ceriani units we've
sampled lately and feature a lever almost 3 in. long for rapid adjustment of the
three-position springs for heavier loads.
When we pulled into our favorite gas station for
a fill up one of the attendants quipped "that's the biggest Honda Super Hawk I
ever saw." Very similar in appearance to recent Hondas, the 750 SF engine is a
vertical Twin with a twin-row chain driving the overhead camshaft. But many of
the similarities between it and the Honda end here. The drive for the tachometer
is located at the left hand end of the camshaft, but the contact breaker points
aren't to be found on the right hand side of the head like a Honda. And instead
of having a 180-deg. crankshaft the Laverda has the crank throws in the same
plane so it fires like a British vertical Twin.
Many manufacturers have adopted the practice of
splitting the crankcase halves horizontally instead of vertically, which
simplifies inspection and rebuilding, and lessens the number of seams where oil
might escape. The Laverda's entire oil supply, which is shared by the
transmission and primary drive/clutch, is located in the crankcase and is
circulated by a double gear pump. After being picked up by the pump the oil is
directed to a centrifugal oil filter which spins impurities to the outside of
the filter casting. The filter is readily accessible by removing a cover on the
left hand side of the engine, and an additional wire mesh screen keeps any large
flakes of aluminum or steel from going through the pump.
Four hefty main bearings support the crankshaft.
The inner two are rollers and the outer two are ball bearings. With such
support, the engine can be spun at high rpm without fear of crankshaft flexing
and bearing failures. Strong steel I-section connecting rods ride on double-row
roller bearings at the big ends and support the pistons using bronze bushings.
Three-ring pistons featuring two compression and an oil scraper ring are used.
Compression ratio is 9.65:1.
Getting the engine's power back to the
transmission is a problem solved in many ways. The British have traditionally
used chains, the Japanese use gears wherever possible. The Laverda follows in
the British tradition and uses a triple-row roller chain whose tension is
maintained by a spring-loaded roller wheel. A hefty clutch runs in an oil bath
and is moderately hard to pull in. However, it takes the strain of drag strip
starts without a whimper and is incredibly smooth in operation. A properly
adjusted chain is quieter than even a helical cut gear, so the primary drive
adds practically no noise to the motor area.
A look at the overall gear ratios will tell the
alert reader that this five-speed gearbox would be well suited to production
racing. Closely spaced, the gear ratios enable the rider to maintain a good rate
of speed while keeping the engine "on the boil" on a twisty road. Shifting can
only be described as flawless, or at least after the initial stiffness
disappeared. Both mainshaft and layshaft are supported on the ends by ball
bearings and the shifting drum is made of aluminum with a steel sheath around it
to minimize wear where the shifter forks ride. Gear lever travel is reasonably
short considering the length of the lever itself.
Although quite large as a package, the
engine/transmission unit is surprisingly delicate in areas where strength is of
minor importance and sufficiently robust where needed. Acting like it does as a
frame member requires that certain areas be strong and they certainly are.
Finish of the engine castings is particularly good with a sandblast finish on
the cylinder head, cylinder barrel and central crankcases and highly polished
castings for the outer covers. Not so smooth as the Japanese die castings, but a
sandblast finish is more effective in dissipating heat than a smooth one.
Many items on the Laverda are of other than
Italian manufacture, and not the least of these are the electrics, excluding the
horns. Mention should be made of the Fiamm horns which emit a blast loud enough
to wake a sleepy tractor-trailer driver from his air-conditioned reverie.
Air-powered versions of these "hooters" come as standard equipment on many of
Italy's high performance sports cars and not enough good can be said about them.
They're the best motorcycle horns we've ever seen.
The battery is also manufactured by Fiamm, but
the generator, starter motor and headlight are Bosch units manufactured in
Germany. The headlight is identical to the ones fitted to the pre-/5 series BMW
machines and features a round key which is inserted to supply current for
starting and running. A turn of the key in one direction turns on the taillight
and parking light, and a flick in the other direction turns on the headlight. No
kickstarter is fitted to the Laverda so it would have to be given the old
run-and-bump treatment if the battery went dead. With a hot battery, starting is
extremely rapid. Just close the handlebar-mounted choke lever half way, touch
the starter button on the right handlebar and the engine bursts to life almost
immediately. Even after killing the engine several times on purpose, the battery
supplied enough current. to spin the engine effortlessly.
Detailing is above average. A nifty compartment
in the rear of the seat can be used to store tools (in addition to a holder
under the seat and behind the battery) or small parcels. Aluminum alloy wheel
rims are employed in an effort to reduce unsprung weight and beautiful stainless
steel fenders with attractive shapes keep road dirt and moisture off the rider.
A small handle is welded to the frame on the left hand side to give the rider a
place to grab when putting the machine on the center stand.
Chrome plating on the exhaust pipes and mufflers,
which has been a weak point on some Italian machines in the past, appears better
than average and the mufflers emit a sound that will gladden the heart of the
four-stroke enthusiast. Deep and mellow, with just a hint of throatiness, the
sound is just beautiful although spirited riding might arouse the local
gendarmerie. The balance tube between the two exhaust pipes helps mid and
top-end power somewhat and reduces the exhaust noise level a trifle. Other items
of German manufacture are the Metzler tires, a rib pattern on the front and a
block pattern on the rear.
Surprises keep cropping up, even in front of the
handlebars. Although calibrated in kph on our test machine the speedometer, as
well as the tachometer, are manufactured in Japan and look suspiciously like
they were swiped off a Honda CB 750.
Aside from a thin looking paint job on the gas
tank and side covers, the 750 SF is a superbly finished motorcycle, but we feel
that most American riders would prefer slightly higher handlebars and a longer
seat for toting their lasses around. But then, that's what the 750 GT is all
about and it will be available for $60 less than the SF.
Source Cycle World 1972