Report From Italy
REPORT FROM ITALY
AERMACCHI/H-D DECENNIAL
CARLO PERELLI
The decennial of the Aermacchi/Harley-Davidson union was celebrated in May at the Schiranna works on the shores of beautiful lake Varese in northern Italy.
It was in early 1960 when executives from Milwaukee, after having looked for cooperation from other Italian firms (among them Moto-Guzzi), reached an agreement for a 50/50 merger with Aermacchi for the supply of lightweights for the American market through their dealer network.
Centerpieces of the Aermacchi production then were the 175and 250pushrod Single machines derived from the all-enclosed Chimera model which was first introduced in 1956, but enjoyed a less than enthusiastic response. So the Chimera was stripped of its enclosure and was offered in a more orthodox guise.
Refusing the 175, Harley-Davidson first got the 250 and then started the production of the well known 50, 65, 100, 125 and 350 models. About
25,000 units are shipped to the USA each year, with increasing prospects when the new 250 and 350 two-stroke Twins and 750 four-stroke Twin will join the range.
To cope with these increasing figures, the Schiranna works, which covered 1300 sq. ft. with 100 employees on the payroll, has been increased in size to 4600 sq. ft., and the labor force increased to 450. Production efficiency is continuously being improved, but in spite of this, Italian fans who rate the Aermacchi/H-D’s as one of the best made machines from their homeland, due to the high standards imposed by the Americans, must spend a long time on the waiting list, because the firstserved are the Americans.
Some notes on the background of Aermacchi will certainly be of interest. The factory Aeronáutica Macchi (soon contracted to Aermacchi) was founded in 1912 for the production of seaplanes, which explains the location of the factory on Lake Varese. It grew to one of the largest in Italy during WW I and continued its progress in the years of peace which followed the war, becoming one of the keenest and most successful contenders for the Schneider Cup. Their C-72 seaplane set a speed record of 709 kph in 1934 which is still unbroken.
During the Second World War, the factory abandoned its primitive production methods and built what is described in many historical publications as the finest fighter plane of the Italian Air Force.
Soon after the end of WW II, a three-wheel truck was chosen for peacetime production. Unorthodox as it was, the truck was a good model and an improved version of it is still in production. It represented the factory’s first step into motorcycling.
Forecasting the motorcycle boom, and wishing to have a go in this field, the Aermacchi bosses set out looking for a good designer who could help produce an appealing lightweight. They found Lino Tonti who designed an open-frame model featuring large wheels and a 125 engine. The engine, a twocycle, swung together with the drive chain, and the luggage compartment, shaped like a gasoline tank, was pivoted at the back of the steering column and offered the motorcycle-minded customers something to grip with their knees when it was up. It also left the “passage” open when it was down for the scooter-loving customers. The year was 1950 and the model was fairly popular. The sport version, its frame “closed” with a real gas tank, competed in the 1951 and 1952 ISDT.
The factory’s first attempt at speed came in 1955 when Lino Tonti designed a “flying cigar” some 10 ft. in length, powered by 50 and 75 engines. The factory’s wind tunnel was used extensively for the necessary tests, and the chain-driven ohc engines featured a 20-degree rearward-inclined cylinder and compression ratio of 10:1. The 75 produced 9 bhp at 11,000 rpm and the 50 developed 7 bhp at 12,000 rpm, both good figures considering the pool petrol and no supercharging.
Massio Pasolini (father of Renzo) took the 75 model to just over 100 mph for the flying start kilometer on the Autostrada near Varese and set many other records in the 50 class as well.
Soon after the record-breaking operation Lino Tonti left Aermacchi and was replaced by Alfredo Bianchi who was formerly with Alfa Romeo and Parilia and a keen motorcyclist before the war. His first task was to translate the Chimera project into a reality, which was submitted to Aermacchi by Count Revelli, a well-known automobile stylist who had raced motorcycles with some success in the Twenties, winning the 1925 Italian GP at Monza.
The Chimera project was not too successful, but another important step in the Italian factory’s history should be recalled. The year was 1960 when Alberto Pagani debuted the prototype of the Golden Wing racer in the 250 class at the German GP. This machine (known to Americans as the Sprint) became one of the best privateers’ mounts available, and was also produced in a 350 version since 1963. The 250 originally had a bore/stroke of 66 by 72mm and developed 22 bhp at 8000 rpm, while the latest version produces at least 10 bhp more at 10,000 rpm!
The 350 model also gained about 10 bhp and a couple of thousand revs throughout its life, and these are the private riders’ mounts: the factory machines churn out somewhat more power and were lately joined by a 408-cc version which has been very successful.
As a result of the merger with Harley-Davidson, the airplane factory moved and now produces civilian models as well as military jet fighters.
NEW DIRT BIKES
The handful of Italian artisans specializing in fine dirt bikes has been joined by Giorgio Mazzilli from Milan.
A good trials rider since the Fifties and a participant in the ISDT several times, Giorgio, the proprietor of a precision machining firm, finally made his dream come true. He has built a number of competition machines using a 125 Maico engine, and personally took his machine to many successes.
So encouraged, he planned an ISDTtype machine over the winter which appeared in the spring, arousing maximum interest among the professionals for its good design and “cost is no object” building philosophy. The first batch of 30 machines was already sold before serious work began on them.
Called the Moto Mazzilli RCS 125, it is now powered by the well-known Sachs 125 five-speeder and is priced at around $900, a reasonable figure considering the construction and performance of this superb machine.
The beautiful frame has a rather low cradle to achieve better stability, but crankcase protection and steering precision are assured by the same gentle bending of the two tubes coming down from the steering head, and by the fitting of a sturdy, steel skid plate. According to Mazzilli it is better, in fact, to enjoy the good stability and handling coming from a low center of gravity than worrying about occasional “bumps” on the bottom of the frame.
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The layout around the steering head is also very fine for strength, as is the central zone. Other outstanding features are adjustable tapered roller bearings at the steering head and the swinging arm spindle, double fixings for the rear shock absorbers, the well-protected steering damper, diagonally folding footrests with spring return, the out-ofthe-way yet well-protected center stand, the light-alloy chainguard with plastic rollers along the bottom run of the chain, and the large light-alloy case under the seat which houses the large paper air filter.
Damping is of course by Ceriani with the front fork being slightly modified to meet Mazzilli’s specifications. Fenders are both in light-alloy and the tires are 3.00-21 front and 3.50-18 rear. The rear wheel is quickly detachable, leaving the chain, brake hub and sprocket intact on the bike. Models will be contesting this year’s ISDT.
DISC-VALVE GUAZZONI
The only Italian firm producing discvalve machines, Guazzoni, has recently introduced a five-transfer, seven port model in 100 and 125 displacements which, since it is graced by an efficient frame, is gaining successes in the amateur dirt events.
Besides the third transfer (in this case with two ports) common to many “strokers,” the new Guazzoni features two vertical grooves (see photo) which act as supplementary transfers (in conjunction with the two holes in the piston) which benefit the pulling power and clean acceleration from low rev ranges. For example, the 100 starts pulling steadily from 4000 rpm; at 6000 rpm it is producing 9 bhp, and 13 bhp are available at the maximum speed of 8500 rpm. The rear-wheel figures for the 125 are over 10 bhp at 5500 rpm and 15 bhp at 8000 rpm. To facilitate rough going, the machines have a sixspeed gearbox, which is offered in three different gearsets for differing tracks and usage.
The engine features a cast iron, largely finned cylinder, claimed to have a more uniform expansion rate than previously employed light-alloy cylinders, while the piston, which carries a single L-type ring, has grooves in the skirt for better lubrication. The cylinder head, however, is made of light-alloy, is amply finned, and features a small, hemispherical combustion chamber and a centrally-located spark plug. Squish effect is obtained by using a slightly domed piston. Bore and stroke on the 125 are 54 by 54mm while the 100’s dimensions are 54 by 48mm.
The crankshaft is supported by three main ball bearings, two on the right (where the magneto and chain-driven primary drive are located) and one on the left (where the rotating disc is housed).
Breathing is accomplished through a 24-mm Dellorto (22mm on the 100) which receives fresh air through a rubber tube connected to a large air box under the seat. The sturdy multi-plate clutch runs in an oil bath on the left side.
The double-cradle frame, of neat and robust design, carries a small oil reservoir on the left for chain lubrication which is protected by the number plate. Damping is by Ceriani. Tire sizes are 2.50-21 front and 3.50-18 rear, weight is 198 lb., wheelbase is 47.24 in., saddle height 30.7 in., ground clearance 9.4 in., and top speeds for the 125 and 100 are 66 mph and 62 mph respectively.
Beautifully finished, though not as divinely as the Mazzilli, the Guazzoni offers plenty of joy to the dirt enthusiast. It is another of the stroker mounts which have taken the supremacy away from the Italian four-strokers in the smaller classes. [Ö]
