Moto Guzzi V 750 S-3

[p6x]

I was browsing the classified adds in Italy, and I found this beauty. This is definitively a stunning example, and the narrative was not the usual copy paste...

I thought that you guys may be interested!

 

It all started with the V7 Sport:

Fast! it was the first commercial motorcycle that really was capable to go over the 200 km/h (124 mph) mark. Powerful with a handling that immediately became legendary; the "formidable V7", as it was described in the adds of the time, only had one great handicap with respect to the competition: the brakes!
Not that Moto Guzzi designers had neglected such an important component. On the contrary, the front was a double cam, four 220mm caliper drum which would have been judged among the best just a few years before.

But the technical evolution clearly demonstrated that disc brakes were superior to drum ones in all braking compartments.

The 1969 CB750, just to give an example, was commercialized with a front disc brake. From then on, all the other manufacturers followed suit.

Moto Guzzi was well aware of their lacking in that domain, and in 1973 they released a kit;

-a double disc with Brembo single piston calipers, modified fork bottom legs/outer tubes, and all the accessories required for the installation. The kit was simple enough to be installed by the owners themselves.
It was an obvious "stop gap" measure in order to wait for a new V7 Sport in line with the contemporary times.

Here's the story:

The arrival of the 750 S.

The double disc is not the sole change of Moto Guzzi's lead motorcycle; renamed 750 S and sold from November 1973. The new bike got a restyling with a sports' seat ending in a "tail stop" which provided a slimier look to the rear of the bike, combined with its new sides.

The seat was almost only suited for a single pilot, but not quite; allowing for the transport of one passenger in relatively good conditions. The back stop helping to keep it together with the incredibly strapping 70 hp V 90 bi-cylinder. The "sporty" line was emphasized by the aggressive colors of the bike; Black, brought out with red, orange or green.

More refined and slender looking than the V7 Sport which metallic green-gold color never seduced the fans, the 750 S looked like a panther ready to pounce.

New engine:

To increase the performance, the chromed exhausts of the V7 Sport were replaced with two blackened "Lafranconi" mufflers sporting a "competition" look and sound, and in tune with the engine.

For the rest, you do not change a winning horse. The 750 S possesses all the technical characteristics of the Sport, from the 750 cc engine derived from the V7 Special with a slightly reduced cubing, and with an alternator in place of the dynamo, a dry clutch, and a drive shaft. The only novelty is the ability to swap the gear change selector to the left, to follow the increasingly complied to standard to have the rear brake command to the right and the gear change to the left of the motorcycle.

1300 bikes were produced until 1975.

New Chassis:

The same thinking was followed with the chassis; the V7 Sport one was conserved, using the same half handle bars, that could be adjusted in height and angle. Something almost unique at the time, because directly clamped on the fork's top tubes. It allowed the user to modify quickly and easily to a "sports" handling from a "cruising" one.

It stayed in production for two years, unchanged but for the turn indicators repeater on the dash board in 1974. Production stopped in the fall of 1975 after 1300 bikes were produced.

Enters the 750 S-3 with rear disc and integral braking:

At the Milan exhibition event of November 1975 the 750 S-3 is presented. Labelled as such because equipped with a rear disc added to the two at the front. But it was not all. Also introduced was "Integral braking", named such because the rear brake pedal would also activate one of the front disc.         

The concept of an "Integral" braking came from an idea of Lino Tonti (design engineer) that Moto Guzzi was very proud to implement. "The bike becomes safer" was one of the catch line used in commercial documentation.

The experimental certification was carried out by the house race and test pilots, such as Vittorio Brambilla and Antonio Piazzalunga.

It appeared for the first time on a competition prototype during the Varrone Grand-Prix in 1971. The prototype was equipped with a 850 cc engine that would later served as a base for the future "Le Mans.

In normal riding, action on the rear brake pedal actuated both the rear and one of the front discs. Using the front lever would actuate the second disc. The system was criticized as taking away some piloting perks and skills, such as using the rear brake to help throw the bike into the curve. However, statistics proved the system was better for typical use by a vast majority of owners. Braking distances were greatly improved and thus was safety.

Moto Guzzi stood behind "Integral" braking and in 1975 all the major motorbikes were equipped with it, I-Convert and 850 Le Mans included.

What changed on the outside:
 

The 750 S-3 shown below is equipped with an optional fairing wrapped around the headlight. An option privileged by a lot of the Mandello fans, which had also been proposed on the 750 S. The engine has that identical look of the bigger cubed sisters. The head cylinders covers have a different shape than those of the S, and are similar to that found on the 850 T/T3 and the I-Convert 1000.

The same "big sisters" look was applied to the front fork, drive shaft and final transmission casing. The gas tank and paint options of the 750 S remained unchanged.

The side covers got changed with an fake "air intake" grid.

The 750 S-3 was only produced to 951 motorcycles. It was the last "Sport" 750 from Moto Guzzi.

Hand-Over:

During that same Milan 1975 exhibition (EICMA nowadays), a new model was introduced. That model would become the favorite of all the Moto Guzzi lovers with a sweet spot for sport looking bikes: the 850 Le Mans. On its first outing, the 850 Le Mans made the 750 S-3 seemed irrelevant. Although the 750 S-3 had reached an enjoyable performance/reliability, the Le Mans just completely outclassed it because of its bigger engine which enticed the "sport" look even more.

Technical characteristics 750 S:
 

Engine: four stroke, bi-cylinder transverse V at 90 degrees air cooled. crank case, cylinder heads and cylinders in light alloy with chromed inserts and valve seats.

Bore and displacement: 82.5 x 70 mmA, Engine capacity 748,388 cc.

Distribution: Duplex chain with push-rods and rockers, two valves per cylinder cam shaft in the crank case. Compression ratio: 9,8:1

Max Power: 72 CV SAE at 7.000 rpm. (71 hp)

Ignition: distributor with dual contact breakers and dual condensers. Two High Tension external coils

Starter: electrical

Lubrication: wet sump with gear pump. Comb Oil filter inside the sump case.

Induction: Two carburetors Dell’Orto VHB 30 CD/CS (D=right S=left).

Tank capacity: 22.5 liters including 3l reserve.

Primary transmission: helical gear drive

Final transmission: drive shaft and conical coupling.

Clutch: dry dual disc on engine fly wheel.

Gear box: 5 gears with shifter on the right hand side (left on request).

Frame: tubed double cradle Cr-Mo steel.

Suspensions:  Hydraulic Front fork Moto Guzzi; Rear swing arm with two adjustable shock absorbers.

Brakes: Front hydraulic dual disc diameter 300 mm with single piston Brembo calipers; rear single drum, single cam 220mm diameter.

Wheels: spoke, alloy rims, front WM2/1.85 x 18" rear WM3/2.15 x 18"; tires: 3.25H-18" 3.50H-18"

Electrical: 12V, battery 12V/32Ah.

Dimensions: (in mm) weight: axle to axle 1.470, length max 2.165, seat height 770, height max. 1.035, width at handlebars 700, min ground clearance 150. dry wet 206 kg, wet weight 225 kg.

Performance: speed max per single gear in km/h: 76, 110, 145, 179, 208.

Gas consumption: as per CUNA: 8,58 litri/100 km.

Variation for the 750 S-3:

Lubrication: removable cartridge oil filter in the sump.
Frame: standard steel.
Brakes: rear hydraulic single disc 242 mm diameter; actuation combined with one of the front disc a.k.a. Integral braking.
Wet weight: 220 kg.

 

 

[pete roper]

Golly! There is a ton of piffle in that wordy diatribe!

[p6x]

17 minutes ago, pete roper said:

Golly! There is a ton of piffle in that wordy diatribe!

You would need to take it up with the owner. I only translated it...

[pete roper]

I'm not criticising you. Just stating that the information given in the piece is wildly wrong and inaccurate.

We did a full engine and driveline rebuild on a 750S a couple of years ago. The owner decided to call it quits before we got to the cycleparts or cosmetics but my oh my wasn't it a slow, disappointing POS. There is a lot of nonsense and folklaw promulgated about the 750 Tontis. Even more so than other Guzzis and that's saying a lot! The one huge advantage they have is they are really smooth and the rod/stroke ratio seems to work really well in this regard but they struggle to make mid forties HP while weighing as much as any other roundfin Tonti. They are grossly under carbureted as well which means they run out of puff when they should be getting into their stride and the camshaft, contrary to popular belief, is the same 'Lawnmower' cam used on all other Tonti's until the MkIV LeMans, (And before anybody starts telling me that the cam timing is different for the V7 Sport I suggest that they go back and look at the setting clearance difference between the Sport and the S. The Sport is a different cam but it's nothing special and yes, back in the day I graphed them both using the same setting clearance, they are very similar.). They are exceptionally pretty though.

[docc]

1 hour ago, pete roper said:

Golly! There is a ton of piffle in that wordy diatribe!

Pretty sure our Greenie Strutters will declare this chief among the piffle:

   " . . . the V7 Sport which metallic green-gold color never seduced the fans . . ."  

I almost bought a 1000S in that green theme. It also had a green frame, which put me off at the time. Later, I learned to rather admire the green frame.

[gstallons]

That green really looks good !

[docc]

2 minutes ago, gstallons said:

That green really looks good !

More recently, Guzzi reintroduced this motif on the V7 Special. I found it disconcerting the stripes did not cross the tank!