Engineering:Laverda 750

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Short description: Italian 750 cc parallel twin motorcycle
Laverda 750
Orange Laverda 750 SF.JPG
Laverda 750SF
ManufacturerLaverda
Production1968-1976
AssemblyBreganze, Italy
PredecessorLaverda 650GT
Engine744 cc (45.4 cu in) Air cooled SOHC 4 stroke parallel twin
Bore / stroke80 cc × 74 cc (4.9 cu in × 4.5 cu in)
Power50–75 bhp (37–56 kW)
TransmissionWet clutch, 5 speed, chain drive
Frame typeSpine
SuspensionFront: telescopic forks
Rear: swinging arm, twin shocks
Wheelbase1,460 mm (57 in)
Weight485 lb (220 kg) (dry)
Footnotes / references
[1][2][3]

The Laverda 750 is a 744 cc (45.4 cu in) air cooled SOHC 4 stroke parallel twin motorcycle produced by the Italian manufacturer Laverda from 1968 to 1976. Developed from the company's 650, the engine's design drew heavily from the Honda CB77. Around 18,000 machines were produced.[4]

Development

Laverda's production was of small capacity singles and twins. General manager, Massimo Laverda, visited the US in 1964 to study the market there. On his return he persuaded his father, Laverda motorcycles founder Francesco Laverda, that to succeed in the US they needed to produce a larger capacity twin.[1] Massimo Laverda brought three motorcycles, a Honda CB77, Norton 650SS and a BMW R69S which were stripped and examined. Although the Laverda took elements from all three,[5] the Luciano Zen designed[6] 650 cc (40 cu in) engine was heavily based on the Honda. Bosch electrics were chosen for reliability.[7] The spine frame and Ceriani suspension gave the bike superior handling.[5][8]

A prototype was shown at the November 1966 Earls Court Show in London. The engine's Honda origins being noticeable.[1] Soon after the show the show the crankshaft phasing was changed from the original 180° to 360° to improve torque delivery. In 1967,[9] American Jack McCormack visited the factory and rode the prototype. McCormack, who had previously worked in marketing for Triumph, Honda and Suzuki in the US, intended to market Laverdas in the US under the American Eagle (motorcycle) (de) brand. Feeling US buyers would prefer a 750 cc machine, he persuaded the factory to enlarge the twin.[5]

Laverda entered a 650 and 3 750s into the Giro d’Italia endurance race in May 1968. The 650 won its class and the 750s all finished in the top 10.[9]

750GT

Laverda 750GT

Going into production in late 1968, the 750GT was the first in Laverda's line of 750s.[3] The GT produced 52 bhp (39 kW) and continued to be produced until 1974 when it was superseded by the GTL.[10]

750S

Launched in 1969, the 750S was a more sporting model than the GT and had a higher compression ratio and produced an extra 8 bhp.[3] The new stronger frame was fitted.[9]

750SF

Laverda 750SF front brake

The 750SF was introduced in 1970 (SF standing for Super Freni eng. Super Brakes) replacing the S model.[3] It used a new frame[1] and was fitted with a 230 mm (9.1 in) twin leading shoe designed by Francesco Laverda[9] rather than the Grimeca item previously used. A balance-pipe was fitted to the exhaust downpipes.[1] The machines were available in a wide range of metallic colours.[11]

The SF models were imported to the UK by Slater Bros and sold in kit form to avoid paying Purchase Tax.[12][11] Around 18,000 of the SF variants were produced in total.[3]

SF1

An upgraded model, the SF1, was introduced in 1973. This used Nippon Denso speedo and rev-counters rather than the Smiths instruments previously used. The crankshaft was strengthened[3] and bigger 36 mm (1.4 in) Dell'Orto pumper carbs fitted. Although the compression ratio had been lowered power output increased to 66 bhp (49 kW) at 7300rpm. A new exhaust was fitted with a larger diameter (1.6 in (41 mm)) with a large collector box under the engine. The collector box often grounded when cornering.[10]

SF2

The model was again updated in 1974 with the addition of a Brembo front disc brake. This was soon upgraded to twin front discs.[1] A dualseat became standard.[3]

The gearshift was changed to the left side for the US market in 1975 and roller bearings replaced the swinging arm bush.[1]

SF3

The final model in the series was introduced in 1976 and had a rear disc brake, cast wheels and a new seat with a fibreglass cowl.[1] The brakes were praised in contemporary road tests.[2] Laverda redesigned the engine of the SF to be lighter and narrower but this never reached production.[10] Production ended in 1976 but the model was available into 1977.[1]

Racing

Prior to the introduction of the SFC, the SF was used in long-distance production racing. Amongst the success in 1970 were:[12][13]

  • Monza 500km - 1st and 3rd
  • Circuit Paalgraven (nl), Oss 24hr - 1st, 2nd and 3rd
  • Circuit Paalgraven, Oss 6hr - 1st
  • Bol d'Or 24hr - 3rd and 6th

  • 1971/2 Laverda 750SF

  • Laverda 750SF1

  • Laverda 750SF1

750SFC

Main page: Engineering:Laverda 750SFC

Introduced in May 1971,[13] the SFC (Super Freni Competizione) was an evolution of the SF and drew from the racers used at the 1970 Bol d'Or.[14] It was a hand-built, full factory production racer finished in orange with a distinctive half-fairing.[15] The machine was made in batches, with each batch identified by the frame number range. In total 549 SFCs were manufactured.[13][16]

750GTL

Laverda 750GTL

Introduced in 1974, the GTL used the GT engine in SF cycle parts. A large tank and touring handlebars were fitted. Production ended in 1977.[10] Several police forces used the GTL including the Italian Polizia Urbana[7]

American models

The 750s imported to the US under the American Eagle brand were fitted with 'buckhorn' handlebars, a fibreglass tank and a restyled seat. The first models offered was the 750 Classic, which used a 60 bhp (45 kW) engine. This was soon renamed the 750 Road Sport when a second model, the 750 Super Sport, was added. The Super Sport used a 68 bhp (51 kW) engine.[17] To publicise the brand, McCormack sponsored Evel Knievel to use 750 Eagles for his stunts.[5]

American Eagle folded in 1970,[18] having sold less than 100 750 twins, including 20-30 machines fitted with a duplex frame designed by Leopardo Tartarini. US West Coast Husqvarna importer Edison Dye became the US importer and imported the models under the Laverda brand and without the 'Americanised' changes.[17]

Technical details

Engine and transmission

Laverda 750SF engine

The SOHC all-alloy twin engine was of unit construction with horizontally split crankcases which helped keeping the engine oil-tight. 4 main bearings supported the crankshaft and the big ends were double-row roller bearings. A duplex chain drove the camshaft and the electric starter used a single chain. A dynamo was mounted on the right end of the crank and the oil pump and points were on the left, which made a wide engine for a twin. The engine has been described as 'over-engineered' and 'unburstable'.[3] Ignition was by points and coil with power supplied by a belt driven Bosch 150 watt dynamo.[11]

A triplex chain took power to the 7 plate wet clutch. A 5 speed gearbox was fitted and final drive was by chain.[3]

Cycle parts

A spine frame was used which didn't have downpipes but used the engine as a stressed member. Front suspension was by Ceriani telescopic forks and rear by swinging arm with twin shock absorbers.[3]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 Backus 2009, p. 1.
  2. ↑ 2.0 2.1 Hill 1976, p. 66.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 Hoseason 2019.
  4. ↑ Olive 2007, p. 60.
  5. ↑ 5.0 5.1 5.2 5.3 Saunders 1991, p. 17.
  6. ↑ Cloesen 2014, p. 88.
  7. ↑ 7.0 7.1 Garson 2005, p. 133.
  8. ↑ Olive 2007, p. 30.
  9. ↑ 9.0 9.1 9.2 9.3 Levenson 2011.
  10. ↑ 10.0 10.1 10.2 10.3 Minton 2013.
  11. ↑ 11.0 11.1 11.2 Minton 2012.
  12. ↑ 12.0 12.1 Slater Laverda Motorcycles.
  13. ↑ 13.0 13.1 13.2 Aynsley 2021.
  14. ↑ Guyony 2016, p. 155.
  15. ↑ Lichter & d'Orleans 2014, p. 80.
  16. ↑ Burgaleta 2017.
  17. ↑ 17.0 17.1 Walneck's Classic Cycle Trader 2002, p. 180.
  18. ↑ Saunders 1991, p. 18.

Bibliography

External links



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