Cycle News - Archive Issues - 1980's

,, ~ m ~ 00 0') ..... IJJVERIl ..... ... ~ rI} :1 bI.l :1 « When Alfieri left Maserati, Massimo's estimation of him was such ("I consider him to be one of the thiff leading experts in the world on high-performance internal comb tion engines.) that he hired him on a consultancy basis for Laverda, allending the factory for one day each week with the aim of rejuvenating the design office and breathing new . lnto Laverda products. Having 'ously worked for Parilla and Lambreua (on their 1950 recorders), Alfieri did have some motorcye e background, though his principal expertise was in the field of V-6 _ V-8 engines. :l us the V-6 Laverda project came Uyo being, with the first engine runmng less than six months after initia~' thanks to a general agreement ~ng the principal collaborators ~qi., Zen and Massimo - as to its baSIC characteristics. Remarkably, the ~n worked straight off the drawiQi::board, with the first dyno run yielding 118 horsepower at the rear wheel from the I,OOOcc engine. The team knew that their target of 140 hor~epower was within easy reach, aQ.d even 160 was feasible. n e Lave,rda 1000 Sei, as it was cfi,ristened by the Italian press, explored new avenues in the realm of mqlorcycle design as a whole, not only in terms of what had gone before al,Laverda. As might be expected, it i"corporated many ideas from the world of four-wheel racing, but still in the context of motorcycling terms. It was nothing like so radical on the chassis side, for example as the present French ELF machine, for one very good reason which Massimo explains, "We wanted to employ new technology, yes, but we had also to consider we were on two wheels, not four. I regard the bike as a combination of the best of both worlds - a halfway house between traditional motorcycle technology and that of the racing car." The entire engine and transmission was made by Laverda, using the high-tech foundry which the family owns near the MV works at Gallarate north of Milan, and which also coincidentally produces castings for Maserati cars and Alfa Romeo racers, as well as Guzzi LeMans engine cases. The six cylinders are arranged in two banks of three, set at a 9O-degree included angle, thus ensuring perfect primary balance, and measure an oversquare 65 x 50mm each, for a capacity of l65.98cc per cylinder or 995.89cc in total. The four valves per cylinder are arranged at an included angle of 28-degrees, and feature 24mm diameter on the inlets and 2~.5mm exhausts, with a single centrallOmm plug per cylinder. Valve timing is 17148 on the inlets and 46/16 on the exhausts, with the valves slightly longer than would otherwise be the case, thanks to the unusual design of the inlet port, which is vertical when the head is filled to the engine, thus permiuing maximum down draft from from the six specially-made Dell'Orto carburetors filled between the V of the engine. Originally ~Ornm units, these were later increased in choke size to ~2mm each, fiued with long velocity stacks reaching up beneath the 6.~ gallon fuel tank. The length of the velocity stacks was found to be crucial in terms of engine power and flexibility. Fuel injection was tested on the engine, using both Kugelgfischer and Lucas indirect systems, but though some valuable lessons were learned for the future, the bike ran on carbs in the Bol d'Or. The twin overhead camshafts are driven by two single-row chains off a jackshaft which runs the whole length of the engine unit, in turn chain dri ven off the front end of the longitudinally-placed single-piece forged crankshaft. This runs in four main plain bearings with Vandervell shells, and thanks to the use of the 90-degree included cylinder angle (which nevertheless results in a fairly compact engine unit measuring only l8-inches wide) only three crankpins are necessary, with each pair of forged steel connecting rods with bronze inserts sharing a common plain bearing big end. Though quieter and more compact, the plain bearing system reo' quires continuously high oil pressure taken care of by two separate oil pumps, gear-driven off the front of the crank with one pressure pump and the other to scavenge the 5.2 quart dry sump system, with its tank under the seat and a single large oil cooler in front of the cylinder block. This complements two quite large water radiators for the 6.~ quart cooling system, with the large centrifugal water pump driven off the front of the jackshaft. Detachable wet cylinder liners are used, only the tops of which are exposed to the coolant since their lower halves are supported by an extended shoulder cast into the combined cylinder and crankcase block casting. The lauer ends at the crankshaft center line, with a cast alloy boh-on sump beneath, while the cylinder head castings are of the "double decker" type, with a separate casting to carry the camshafts and inverted bucket tappets. The whole design represents a scaled-down lillIe sister of Al£ieri's 2.7 liter Maserati V-6 unit as employed in the Citroen SM and the Italian firm's own Merak couple, with the important difference that the car engine only featured two valves per cylinder. A skew gear off the jackshaft drives the large Marelli distributor which is mounted behind the steering head. Coupled with a very expensive Dinaplex electronic ignition unit from the same supplier which cost a cool million lire each (around $675) in 1978, and which was originally developed for the V-12 Ferrari GP car before being used on the V-6 Ferrari Dino sports coupe in modified form, this provides a high-intensity spark for IO,OOO-plus rpm running. An electric starter is fitted (a special switch must be flicked on the Dina- plex for jump-starting if the unit is not to be damaged irreparably) which together with the electric fuel pump and endurance racing lighting set requires the fitting of a generator to charge the large balle.ry mounted beside the oil tank on the right, under the seat. Ignition advance is a conservative ~8-degrees, and compression ratio 10.5:1, with excellent fuel economy thanks to the efficient combustion generated by the paired valves, narrow valve angle, and flat-top alloy pistons. The five-speed gearbox (with left foot change) is enclosed in its own separate casing which is bolted on to the back of the crankcase, with originally a BMW-type swinging fork enclosing the shaft drive up the right arm to the hypoid final drive unit. Suspension was by means of a single long damper unit mounted horizontally along the crankshaft axis beneath the gearbox, and worked by a bellcrank system. But whereas the engine proved immediately successful in testing, as soon as it was filled with cycle parts, which employed the unit as a stressed member with a triangulated tubular subframe bolted to the front of the engine to carry the front suspension, the swingarm pivoting in the gearbox casing (which also usefully resulted in coaxial location of same with the drive shaft) and another tubular subframe to carry the seat, the team's problems began. "Our difficulty was not with the engine's power but with its transmission and the problems of torque reaction," recalls Massimo Laverda. "There were two hurdles to overcome: first was the inevitable one that if you have a longitudinal crankshaft in any bike you must inevitably suffer adverse torque reaction as the engine rotates across the frame. That's not much of a problem with a 70 horsepower BMW or Guzzi, but with up to 140 horsepower on our V-6 at 10,000 rpm or so, we experienced terrible handling problems. The solution was to place the gearbox to one side and 19

• Cover