Report From Italy

REPORT FROM ITALY

CARLO PERELLI

TWO ITALIAN RACERS

We recently got acquainted with two “over-the-counter” Italian racers featuring quite opposite characteristics— the 125 single cylinder two-stroke Aermacchi-H-D Golden Wing and the 750 twin-cylinder, single ohc Laverda SF-C (available in the U.S. on special order, only).

Always well inclined toward private road racers, Aermacchi-H-D decided to offer a 125 as well. After careful designing and testing, production of the new model, called the Golden Wing like its bigger brothers, started in the Winter of 1966-67.

Now 350 units have been turned out, mostly going to Italian buyers (winning no less than five championships while competing against more sophisticated machinery). Some went abroad, too. (John Dodds rode one to a win on the 1970 German GP at the Nurburgring, in atrocious weather.)

Keynotes of the Aermacchi Golden Wing 125 are sturdiness, simplicity and ease of maintenance. These are real bonuses for the private rider, but do not cause mediocre performances. The 1972 version offers 25 bhp at the rear wheel, good to top 118 mph—not bad for a piston port-controlled air-cooled “stroker.”

When it was born, the Golden Wing had 20 bhp at 9200 rpm, a 27mm Dellorto carburetor, a magneto flywheel with external HT coil, a five-speed gearbox, 2.50-18 tires, a weight of 187 lb. dry and a top speed of 109 mph. The cylinder had the usual two transfer ports plus the inlet and exhaust ports.

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The performance increase on the 1972 models has been chiefly obtained by “digging” three supplementary transfers into the cylinder wall, “working” in conjunction with three holes in the piston (see photos). The carburetor bore has been taken up to 30mm. Electronic ignition was specially developed for the machine by the Italian firm Dansi of Varese. One more cog added in the gearbox, plus a slight weight decrease (from 187 to 176 lb.), also contribute to improved performance.

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First impressions of the Golden Wing are of good handling and lightness. Incidentally, the factory has experimented with a light alloy, chrome-bored cylinder, weighing only 6.6 lb. against the 19 lb. of the standard, full iron barrel, but the steering was becoming too light.

Under 7000 rpm, the engine gives practically nothing. It starts pulling from 8500 rpm and the useful range is between 9500 and 10,800, quite wide for a racing 125. Vibration is at a minimum, thanks to the rubber engine mounting, while the controls are all well set, light and positive to operate.

The highest rpm drop in changing up is only 500 rpm and on reopening the throttle the rev counter needle returns nearly instantly over the red zone.

For quicker action in changing down, instead of closing the throttle one presses the kill button near the left handgrip, but this maneuver must be perfectly mastered; otherwise, one loses more time than in the orthodox way and, on activating the ignition again, the fresh gases accumulated in the combustion chamber make for powerful explosions that do harm to the engine, especially the alignment of the inner flywheels and the caged rollers of the con rod. The kill button is also used, shortly before braking and changing down, to “refresh” the engine and avoid seizure troubles. Lubrication is by simple five percent (20:1) fuel-oil mixture.

Braking is assured at the front by a four leading shoe, 180mm device specially developed by Fontana for the Golden Wing. At the rear, the brake is the same as employed on the standard roadsters. So stopping is good at the front and rather weak at the rear.

Suspension is Ceriani and here again the front is fine while the rear is a bit on the rigid side. Since weight distribution is rather forward, the rear wheel tends to jump a bit. Luckily the bike tracks well in fast bends, thus giving no unexpected thrills to the rider.

Size and riding position of the Golden Wing are obviously for lightweight pilots, so Paul Smart types are advised to abstain. They would also adversely affect the power-to-weight ratio.

LAVERDA SF-C

The Laverda SF-C though, with its abundant dimensions, dry weight of 466 lb. and muscular effort required to throw it about, especially on twisty courses, is particularly suited to Paul Smart types.

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Production of the Laverda SF-C began a year ago and now more than 200 mounts have been turned out. Like for the Golden Wing, demand exceeds supply, so one must have some merit to get one.

The SF-C enjoyed a brilliant 1971 season, winning both at home and abroad, capturing the Oss and Barcelona 24 Hours, 2nd place in the French Bol d’Or (also 24 hours) and successes in the Italian 500 kms at Rome and Modena.

Laverda is very keen on production racing, as it entered the motorcycle business in the late 40s and raced 75and lOOcc “pushrods” which were practically unbeatable in such tough events as the Milan-Taranto (868 miles) and the Tour of Italy (2170 miles). And now factory boss Massimo Laverda and technical director Luciano Zen are going to Daytona to have a close look at that form of racing, so something even more exciting may come out!

The 1972 Laverda SF-C powerhouse, marked for its sturdiness and slightly improved over last year’s type, now has 70 bhp at 7500 rpm at the rear wheel, but for short events (up to 310 miles) it can be revved up to 8000 in the lower gears. Vibration is limited (good for long distance racing) and is felt just between 6700 and 7000 rpm. Rather annoying, on the contrary, are the “shivering” of the front fairing (disturbing the vision), and the clutch operation, which is on the hard side, as usual with the big Laverdas.

In road trim, with mufflers, pulling power starts from 4000 rpm; while in racing trim, with reverse cone megaphones and different jetting, some 500 revs more are needed to pull away nicely. From that limit, power is constant and abundant, over a range of 3000 rpm. Top speed is 133 mph.

Carburetion is by two Spanish 36mm Amal concentrics, which have given better results than the Italian Dellortos. Valve diameters are 41.5mm (inlet) and 35.5mm (exhaust). Electric starting has, of course, been retained and, provided one covers the mouths of the carbs with his hands for a moment (they have no chokes), firing from cold is practically immediate. This is particularly good for Le Mans-type starting!

The five-speed gearbox works perfectly and bears every abuse; the same can be reported for the clutch. The 230 x 30mm Laverda brakes, of twin cam design at both ends, do a good job, but the bike can be ordered with a 230 x 25mm four leading shoe Ceriani anchor at the front. Under hard racing conditions and during dry weather, the Ceriani is better; but otherwise, and especially in the wet, the Laverda products have an edge over the Ceriani, because their shoes, although well cooled, are completely insulated. They also require less maintenance.

Laverda road holding ability has never gained top marks, as its center of gravity is rather high. But on the 1972 SF-C this condition has been improved. The Ceriani suspension has been refined, the swinging arm has been reinforced (now acting on plain bearings instead of plastic bushes) and the Borrani rims have been both shod with 4.10-18 K81 Dunlops. The results are very good and, in fact, even in the fast Monza bend (where we gained our knowledge of the SF-C) the machine does not “move.”