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Difference between revisions of "Laverda SF750"

Laverda SF750 (edit)

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The SF has been around for a couple of years and readers may recall that we took one to Cologne last year. Since then there have been a few changes. One is quite un­able to avoid some sort of comparison be­tween the engine unit and that fitted by Honda a few years back and one imagines that Laverda have had it said so often that they may well be a little bored by the subject. Who cares if it does look like a Honda engine; it is how it goes that counts. It is, of course, a 'twin-cylinder four-stroke with duplex chain-driven overhead camshaft valve operation. The chain is sensibly retained by a split link so that it is not necessary to remove the crankshaft to replace it. New for this year is a cylinder head developed on that used in the production racing SFC. It comes as a package designed to make the machine go faster with less effort. Larger, 36mm, carburetors are used which incor­porates a mechanical car-type injection pump for starting. Slipping the throttle results in a squirt of petrol and, if overdone, a wet plug. A new air cleaner of the paper element type is used. Compression ratio has taken a drop, from 9y to 1'to 8.9 to 1, enabling three-star petrol to be used. Another significant change is the redesigning of the exhaust system to comply with strict German silencing laws. The old ones were a. bit sporting. These pipes have a large diameter balancing pipe, uncharacteristically a little on the ugly side.
The SF has been around for a couple of years and readers may recall that we took one to Cologne last year. Since then there have been a few changes. One is quite un­able to avoid some sort of comparison be­tween the engine unit and that fitted by Honda a few years back and one imagines that Laverda have had it said so often that they may well be a little bored by the subject. Who cares if it does look like a Honda engine; it is how it goes that counts. It is, of course, a 'twin-cylinder four-stroke with duplex chain-driven overhead camshaft valve operation. The chain is sensibly retained by a split link so that it is not necessary to remove the crankshaft to replace it. New for this year is a cylinder head developed on that used in the production racing SFC. It comes as a package designed to make the machine go faster with less effort. Larger, 36mm, carburetors are used which incor­porates a mechanical car-type injection pump for starting. Slipping the throttle results in a squirt of petrol and, if overdone, a wet plug. A new air cleaner of the paper element type is used. Compression ratio has taken a drop, from 9y to 1'to 8.9 to 1, enabling three-star petrol to be used. Another significant change is the redesigning of the exhaust system to comply with strict German silencing laws. The old ones were a. bit sporting. These pipes have a large diameter balancing pipe, uncharacteristically a little on the ugly side.


The camshaft actuating chain runs up between the cylinders, with the camshaft running on four bearings. The crankshaft, too, has four bearings, two spanning the double camshaft sprocket inside the flywheel and one at each end. Outside the right-hand main bearing is the starter motor drive-chain sprocket. The 0.95 h.p. motor is mounted behind the engine, above the gearbox, and the crankshaft is turned via a single row chain. Finally at the right-hand end of the crankshaft there is the dynamo drive pulley with the belt drive running to the forward-mounted 150w dynamo. The left-hand end is also crowded with first of all a treble sprocket to take the triplex primary drive chain, then a smaller gear, sharing the same drive spline and run­ning to the oil pump drive gear. The oil pump is of gear type delivering three litres a minute. The contact-breaker assembly, with twin contacts, is mounted outside the oil pump drive gear so it is a matter of debate whether one calls this the oil pump gear or the timing gear! All this activity at the ends of the crankshaft makes for a rather wide engine and one would imagine that there is a good case for fitting the safety bars that are available as an optional extra. A mild slide down the road could be very expensive.
The camshaft actuating chain runs up between the cylinders, with the camshaft running on four bearings. The crankshaft, too, has four bearings, two spanning the double camshaft sprocket inside the flywheel and one at each end. Outside the right-hand main bearing is the starter motor drive-chain sprocket. The 0.95 h.p. motor is mounted behind the engine, above the gearbox, and the crankshaft is turned via a single row chain. Finally at the right-hand end of the crankshaft there is the dynamo drive pulley with the belt drive running to the forward-mounted 150w dynamo. The left-hand end is also crowded with first of all a treble sprocket to take the triplex primary drive chain, then a smaller gear, sharing the same drive spline and run­ning to the oil pump drive gear. The oil pump is of gear type delivering three liters a minute. The contact-breaker assembly, with twin contacts, is mounted outside the oil pump drive gear so it is a matter of debate whether one calls this the oil pump gear or the timing gear! All this activity at the ends of the crankshaft makes for a rather wide engine and one would imagine that there is a good case for fitting the safety bars that are available as an optional extra. A mild slide down the road could be very expensive.


The gearbox: five speeds with overall gearing of 12.0, 8.6, 6.3,.5.,6. and 4.6 to 1. The crankcase splits horizontally to reveal both the innards of the gearbox and the crankshaft. The seven-plate dry clutch is housed at the left-hand end of the gearbox. The gear change lever, as is common on many Italian machines, is on the British side, the right. Laverda, of course, like everyone else, are going to have to change it to the left by 1975 if they wish to sell their machinery in the United States of America.
The gearbox: five speeds with overall gearing of 12.0, 8.6, 6.3,.5.,6. and 4.6 to 1. The crankcase splits horizontally to reveal both the innards of the gearbox and the crankshaft. The seven-plate dry clutch is housed at the left-hand end of the gearbox. The gear change lever, as is common on many Italian machines, is on the British side, the right. Laverda, of course, like everyone else, are going to have to change it to the left by 1975 if they wish to sell their machinery in the United States of America.
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The electrics include a Bosch 12v dynamo and starter motor; It is not all Bosch, though, for the headlamp is Laverda's own design, a shell identical to that on the BMW. Electrical controls are by Lucas. Most road-testers (including ourselves) have been luke­warm about the latest Lucas dipswitch assem­blies, claiming that they look as though they are likely to snap off if given abrupt treat­ment. The fact is they have been out for a couple of years now and we cannot recall seeing any that have suffered this fate. Left and right controls are the same, the left hav­ing dipswitch, horn and cut-out button and the right flashers, starter and headlamp flasher. The flashing indicators fly in the face of convention by being wired so that "up" is for right and "down" is for left. Most other manufacturers seem to opt for the opposite, surely more logical, arrange­ment. The headlamp beam was just about on a par with most of its rivals, which is to say that it was acceptable but not special. The horn was special. A magnificent bellow escaped from the twin horns, a rare treat for the road-tester used to the pathetic bleat of most motorcycle horns. If any other enterprising manufacturer wants to use them they are made by Fiamm, of Italy. Showing that they are willing to go anywhere in the world to find the right part for the job Laverda have this year introduced Japanese tachometers and speedometers similar to those used until recently on the big Hondas. (They used to fit Smiths.)
The electrics include a Bosch 12v dynamo and starter motor; It is not all Bosch, though, for the headlamp is Laverda's own design, a shell identical to that on the BMW. Electrical controls are by Lucas. Most road-testers (including ourselves) have been luke­warm about the latest Lucas dipswitch assem­blies, claiming that they look as though they are likely to snap off if given abrupt treat­ment. The fact is they have been out for a couple of years now and we cannot recall seeing any that have suffered this fate. Left and right controls are the same, the left hav­ing dipswitch, horn and cut-out button and the right flashers, starter and headlamp flasher. The flashing indicators fly in the face of convention by being wired so that "up" is for right and "down" is for left. Most other manufacturers seem to opt for the opposite, surely more logical, arrange­ment. The headlamp beam was just about on a par with most of its rivals, which is to say that it was acceptable but not special. The horn was special. A magnificent bellow escaped from the twin horns, a rare treat for the road-tester used to the pathetic bleat of most motorcycle horns. If any other enterprising manufacturer wants to use them they are made by Fiamm, of Italy. Showing that they are willing to go anywhere in the world to find the right part for the job Laverda have this year introduced Japanese tachometers and speedometers similar to those used until recently on the big Hondas. (They used to fit Smiths.)


The frame: Using the engine as part of the chassis, the actual frame consists of two robust top tubes run­ning from the head to the rear of the dual-seat. Another two tubes loop up from the rear swinging-arm bottom pivot point, meet­ing the two top tubes for about 12in and then curving down to join the bottom of the steering head. We have never seen anything quite like it before but the question is, "does it work". The answer is yes. A tendency ll at high speed, evident in last year's models, has been, at least under the condi­tions that we tried the machine, eliminated. The importers felt that this wandering may have been due to the Metzler tyres fitted and uiey recommend TTlOOs. Future production models will have TTlOOs, made by Pirelli in Italy. Not surprisingly, front and rear sus­pension units are made by Ceriani. Brakes are Laverda's own, beautifully made, each of 230mm and having 21s actuation. They were outstanding. We were not too happy with the choice of seat on the last Laverda we had, feeling that single seats were limited in scope. What we did not realize was that one had the option of racing seat or dual seat. We were told that many buyers take both. Our test machine had a dual seat. In most respects it was very good but it did conspire with two other of the machine's virtues to create a problem. It sloped forward and the petrol tank was quite deep at the rear. If a pillion passenger was carried and the brakes were applied with much enthusiasm, in cer­tain circumstances the passenger would slide forward and the unwary pilot would risk ruin on the petrol tank.
The frame: Using the engine as part of the chassis, the actual frame consists of two robust top tubes run­ning from the head to the rear of the dual-seat. Another two tubes loop up from the rear swinging-arm bottom pivot point, meet­ing the two top tubes for about 12in and then curving down to join the bottom of the steering head. We have never seen anything quite like it before but the question is, "does it work". The answer is yes. A tendency ll at high speed, evident in last year's models, has been, at least under the condi­tions that we tried the machine, eliminated. The importers felt that this wandering may have been due to the Metzler tires fitted and uiey recommend TTlOOs. Future production models will have TTlOOs, made by Pirelli in Italy. Not surprisingly, front and rear sus­pension units are made by Ceriani. Brakes are Laverda's own, beautifully made, each of 230mm and having 21s actuation. They were outstanding. We were not too happy with the choice of seat on the last Laverda we had, feeling that single seats were limited in scope. What we did not realize was that one had the option of racing seat or dual seat. We were told that many buyers take both. Our test machine had a dual seat. In most respects it was very good but it did conspire with two other of the machine's virtues to create a problem. It sloped forward and the petrol tank was quite deep at the rear. If a pillion passenger was carried and the brakes were applied with much enthusiasm, in cer­tain circumstances the passenger would slide forward and the unwary pilot would risk ruin on the petrol tank.


Just to sit astride the Laverda SF was a pleasure. The machine felt just about as perfect as a good motorcycle can . . . the riding position, the controls and the whole feel of the machine were just right for this tester. If one had to form an opinion with­out riding anywhere it would be that this had to be one of the best motorcycles made. The suspicious might well be wondering if we are not building up to put the boot in. It is not quite as serious as that but, in spite of our wanting to praise every aspect of the machine and making every allowance for our prejudices, one was still forced to the conclusion that, when the chips are down, it has this built-in problem. It is still a vertical twin! Naturally this has virtues as well but it has one big almost insurmountable vice: a vertical twin by its very definition vibrates and even Laverda, with what must rate as one of the most robust, carefully designed and assembled engines made, have been un­able completely to cure the problem.
Just to sit astride the Laverda SF was a pleasure. The machine felt just about as perfect as a good motorcycle can . . . the riding position, the controls and the whole feel of the machine were just right for this tester. If one had to form an opinion with­out riding anywhere it would be that this had to be one of the best motorcycles made. The suspicious might well be wondering if we are not building up to put the boot in. It is not quite as serious as that but, in spite of our wanting to praise every aspect of the machine and making every allowance for our prejudices, one was still forced to the conclusion that, when the chips are down, it has this built-in problem. It is still a vertical twin! Naturally this has virtues as well but it has one big almost insurmountable vice: a vertical twin by its very definition vibrates and even Laverda, with what must rate as one of the most robust, carefully designed and assembled engines made, have been un­able completely to cure the problem.
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