Moto Guzzi 750S3

 

 

 

Make Model

Moto Guzzi 750S3

Year

1975

Engine

Four stroke, 90° V twin, longitudinally mounted, OHV, 2 valve per cylinder.

Capacity 748.4 cc / 45.6 cu-in
Bore x Stroke 92.5 x 70.2 mm
Cooling System Air cooled
Compression Ratio 9.8:1

Induction

2x 30mm Dell'Orto carburetors

Ignition 

Battery with double contact breaker with automatic advance
Starting Electric

Max Power

70 hp / 52 kW @ 7000 rpm

Max Torque

NA

Transmission 

5 Speed
Final Drive Shaft

Front Suspension

Telescopic forks

Rear Suspension

Swing arm with single damper.

Front Brakes

2x 300mm discs

Rear Brakes

Single 242mm disc

Front Tyre

3.25H-18

Rear Tyre

3.50H-18

Dry Weight 

206 kg / 454 lbs

Fuel Capacity

22 Litres / 5.8 US gal

Of all the retro-bikes produced since motorcycle manufacturers discovered the value of nostalgia, none can have been a more faithful reproduction than the handsome naked 1000S that Moto Guzzi introduced in 1990. The reason is clear when you set eyes on the 1975-model 750 S3. The bike on which the 1000S was based is a gorgeous machine, with its long and low shape, big transverse V-twin motor, and especially the sculpted fuel tank with its two broad diagonal stripes.

Back in the mid-Seventies, that distinctive naked silhouette belonged to a sports bike, not a piece of two-wheeled nostalgia. The S3 didn't merely look good, it also had the performance to match: stable handling, excellent braking, and an ability to cover long distances at a speed that few other mid-Seventies machines could match.

The S3 owed its name to just one aspect of its chassis: the triple-disc linked braking system that was introduced on this bike and also the 850 T3 tourer. The S3 was a development of the similarly styled 750 S, which had twin front discs and a drum rear—and which itself was developed from Guzzi's first sporting V-twin, the -drum-braked V7 Sport.

Even without the linked system, that trio of big 300 mm (11.8 in) discs and their Brembo calipers would have been a noteworthy feature in 1975, when rivals as glamorous and expensive as BMW's R90S flagship made do with a rear drum. But more than any one particular feature, it's the Guzzi's combination of parts—from the clip-on bars via the big lump of engine all the way to the black, shark's-gill tailpipes—that makes this bike so stylish and purposeful.

The S3's pushrod-operated 90-degree V-vwin engine was heavily based on that of the V7 Sport, sharing its bore and stroke dimensions of 82.5 x 70 mm (for a capacity of 748cc), its 9.8:1 compression ratio, and most mechanical parts. But Guzzi had made some changes, most notably incorporating a proper oil filter in the crankcases (the Sport made do with a mere strainer), and replacing the earlier model's helical gear camshaft drive with a cheaper chain and sprockets.

One of the Guzzi's main assets was its lack of height, which was largely due to the way in which the steel frame's main spine ran between those big sticking-out cylinders. This meant that the thinly padded seat was just 730 mm (29 in) from the ground, making the S3 manageable for shorter riders. But the high footrests and the long stretch forward across the tank to the clip-ons combine with this to make a bike that would doubtless be perfectly comfortable for a chimpanzee, but results in stretched arms and cramped knees for anyone else.

The S3 fired up with that age-old transverse V-twin lurch to the right, but it didn't have quite as much low-rev judder as the firm's bigger V-twins. The sensations it delivered were all unmistakably Guzzi, though: the shaft-drive bike's rather sudden take-off when I let out the clutch, the pressure from the tappet-covers on my knees, and most of all the aural blend of ticking valvegear, chuffing exhaust note, and hollow induction note as the revs rose.

This bike's throttle was rather heavy, and the effort of wrenching it wide open wasn't rewarded in as dramatic a way as I'd expected. With a claimed maximum of 72 BHP at 7000 RPM, the S3 was powerful, on paper. But perhaps the similar V7 Sport's claimed output of 52 BHP, delivered at the rear wheel rather than the crankshaft, gave-a more accurate picture of the later model's performance. (Manufacturers' figures during this period were notoriously unreliable.)

What was for sure was that the S3's 747cc motor had less low and midrange torque than the larger-capacity Guzzis that followed it, and needed to be revved between 5000 RPM and the 7000 RPM yellow-line to give its best, which wasn't what I'd expected of a big Guzzi. Even then, the acceleration was not exactly dramatic. The S3's top speed when tested in 1975 was 125 mph (200 km/h), and its standing quarter an even less impressive 14.6 seconds—over a second slower than the R90S, let alone the mighty Z1.

But if the Guzzi took a fair bit of time to reach an indicated 90 mph (145 km/h), what it excelled at was holding that speed to the horizon and beyond. The S3's smoothness combined with tall gearing to make for effortless riding. Its lack of midrange necessitated fairly frequent use of the rather slow five-speed gearbox, but the Guzzi felt reassuringly strong and lightly stressed.

The trio of big linked discs meant that the S3 could brake hard, too—it's doubtful whether any bike stopped more quickly in 75. Treading on the foot-pedal operated the rear Brembo, plus one of the front pair of discs; the handlebar lever added the second front disc, and could be ignored to allow easier throttle-blipping if you weren't trying to use every bit of the front tire's grip.

Handling was also very impressive, in a traditional Guzzi way. The S3 steered pretty slowly but was so stable that nothing would throw it off its cornering line. Suspension at both ends was firm without being excessively harsh, though the heavy shaft-drive rear end inevitably felt a bit remote. And the grip from this bike's modern 18-inch Michelin rubber showed ground clearance to be excellent.

Details such as the hard-to-use centerstand, dim warning lights, and awful switchgear lost the Guzzi marks, as did its high price. But to the average mid-Seventies motorcyclist, any complaints would have been far outweighed by the S3's glamour and performance. Even so, only a relatively small number of S3s were produced before Guzzi replaced it with the 850cc Le Mans a year later. The sleek and beautiful 750 S3 was gone, but it was not forgotten. The appearance of the 1000S, 15 years later, would provide proof of that.

From. Bike, dec. 1975

"Starting with the heart of the matter, the engine, let's point out that this is one of the surprisingly few motorcycles that will hold cruis ing speeds in the high nineties without feeling like it's going to scatte its internals over the tarmac.

But while the Guzzi is an effortless high speed cruiser, it will fall short of many people's expectations because it doesn't accelerate in the manner to which we've become accustomed in our latter-day 'superbikes'... Even when you buzz the motor above five grand the bike doesn't seem to lunge forward with the brute force of other biggies.

The motor has an odd wheezing sound that somehow fits the bike's loping style. Laying over the big tank, you aim the Guzzi into turns and it feels very predictable, very reassuring... However the Guzzi isn't the day-long full tilt land cruiser that we'd hoped for. The riding position, not the machine itself, makes that impossible."

Source Superbike of the seventies