Report From Italy
REPORT FROM ITALY
CARLO PERELLI
MORINI 350 V-TWIN
The Morini fidelity pact with the single-cylinder lasted until the 1971 Milan Show. As a matter of fact, since its foundation by ex-racer Alfonso Morini following World War II, the Bologna-based factory never built anything but single-cylinder models ranging from 50cc to 250cc.
The legendary 250 dohc of the 1 958-1 965 period, which rocketed Agostini to fame, will always be remembered (the only surviving example is now proudly displayed in the entrance hall of the firm). But also, production models got well-deserved fame for reliability, simplicity, sturdiness and good performance.
But times are changing. When deciding on a 350, the management (now headed by the daughter of Alfonso Morini, who died in 1969) chose the Twin, to “blend” most of the Singlej advantages with those of the multicylinder. This is typical of the down-toearth, practical mentality reigning in the Bologna firm.
The engine layout chosen is the most antique in motorcycle technique—the longitudinal V (always valid for good balance and limited width), but they made some refinements, of course.
To start with, the problem of cooling the rear cylinder was resolved, according to factory technicians, by widening the V angle to 72 degrees, by off-setting the rear cylinder by 50mm compared to the front one and inverting the exhaust positions (the front to the right, the left to the rear). Now, the rear exhaust area is not subjected to air warmed-up by the front cylinder. Moreover, the cylinders are in light alloy. And, it has been found by lengthy testing that the legs of the rider deflect an effective stream of fresh air on the rear cylinder, to the point that in some cases it was cooler than the ront one. In any case, thermal tests have registered a difference of 15 degrees at the most between the front cylinder and the rear one, which is practically nothing.
This new Morini engine, although old for the cylinder layout, shows some quite modern features—the flat heads, with the combustion chambers right in the pistons tops, the camshaft driven by rubber belt, the electronic ignition, the dry-type clutch and the in-unit six-speed gearbox.
The flat head feature, successfully tested on the 175cc ISDT-type trial machines which won the Italian Championship, the Valli Bergamasche and other major events in 1971 (including four Golds at the ISDT), is said to assure better squish and combustion. Also of note are parallel valves (a tradition for Morini) to eliminate damage in case of over-revving, and the “serpentine” of the inlet duct, developed after long tests to give the fresh gas charge entering the combustion chamber a special “swirl,” to increase squish effect. Also a good thing, the spark plugs are right at the center of the combustion chamber.
The pushrod operated ohv timing system has been chosen mainly to facilitate maintenance and repairs. Moreover, it’s simpler and doesn’t impair performance. In fact, the new Morini engine revs merrily up to 8500 rpm, giving 38.6 bhp (SAE), good for a top speed of 100 mph.
The camshaft is placed high at the right (to reduce pushrod length) and is driven by a rather large rubber belt which has no need of a tensioner since its “travel” is very short. To our knowledge this is the first time a rubber belt has been used for production motorcycles; among the virtues of this feature are economy and silent operation.
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The camshaft passes through the base of the cylinder V to actuate the electronic ignition system on the left hand side, while the 12V-100W generator is keyed directly to the crankshaft’s right end. The electronic ignition has a particularly wide automatic advance range (from 10 degrees after tdc to 34 degrees before tdc) to facilitate kick starting.
The one-piece crankshaft carries a left side helical gear for the primary drive, with a 2.275:1 reduction, and also drives the gear oil pump, which incorporates an automatic valve to adjust pressure.
The in unit six-speed, and the dry-type 10-disc clutch are good companions for the lively engine.
Vital statistics include: Bore and
stroke, 62x57x2 for a displacement of 344cc; valve diameter 29.5mm at the inlet and 22.5 at the exhaust; c.r., of 10:1, Dellorto VHB 25mm carburetors with a common filter is located under the tank.
Morini cycle parts are strictly orthodox but the fuel tank is provided with a so-called “electro-magnetic tap.” In other words, fuel flow is allowed only when inserting the ignition key. This ingenious system is to prevent engine “flooding;” on the other hand, the reserve is activated manually, with the usual small lever.
The double cradle frame is suspended by Marzocchi units at both ends and tires are 3.50-18 at the front and 4.10-18 at the rear. Brakes are twin cam at the front and a single cam at the rear. A disc is planned for the front, as soon as the Italian industry offers a good one to motorcycle builders and, as we are talking about future plans, let’s add that this model (simply called 350 Twin) will have a sports version and a 500 version.
After more than a year since its introduction at the 1971 Milan Show, the 350 Morini has at long last arrived in dealer showrooms. There was great anticipation over this bike, since it is the first modern Italian 350, appealing to many customers who can’t afford the big guns either for economic reasons or riding capabilities. The price is around $1100.
A brief gallop on the new Morini proved that its main virtues are maneuverability and lively temperament. Wheelbase is 55.6 in., dry weight is 316 lb. and the safe rev limit is 9200 rpm. The high power, the natural riding position, the functional controls, the minimal vibration, the excellent clutch and the well-spaced six-speed gearbox make the new model from Bologna appealing. Top speed in sixth gear at 8200 rpm is 103 mph.
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“THE IDEAL BIKE”
The jury of the “Premio Varrone,” represented by a large number of Italy’s most advance enthusiasts, has laid down the features of the “ideal bike” and is now circulating them among Italian as well as foreign manufacturers, trusting that at least some of its requests will be taken into consideration and applied to future production.
The ideal bike for the Premio Varrone jury should have: weight not over 375 lb., displacement and power necessary for the following performances: top speed of 118 mph; acceleration good for a 12.5 sec. standing quarter mile; cruising speed with two people aboard of 99 mph; range at cruising speed not less than 185 miles.
Disc brakes to both wheels; light alloy wheels; five-speed gearbox; final drive by shaft; air-cooling; fuel injection; four-stroke engines with maximum 2/3 cylinders; adjustable handlebar and saddle; gearchange lever on the left and standardized controls; adjustable front and rear suspension; rider protection against atmospheric elements; pressed sheet (box) type frame with a carrying capacity of 45 lb. of luggage and of course the capability of carrying a passenger. Add to this an automatic center stand, warning lights for the electrics, and a hydraulic circuit for the brakes and you have a most desirable product.
Some of the above features are matters of opinion, others are well grounded and should really give food for though to the various factories technicians.
GILERA ISDT EFFORT
With the USA ISDT in mind and possible links with the rich local market, Güera is making a great deal of effort for the coming season. It has signed Italian No. 1 dirt rider Alessandro Gritti with a contract worthy of a top GP rider and still allow him to ride Puch machines in scrambling; moreover, they are paying wages unknown in Italy, to other excellent dirt riders such as Paganessi, Brissoni and Oldrati, all well experienced in ISDT competition.
It is the general opinion that with appropriate machinery these riders could challenge and prove superior to the toughest international competition. But which machine is Güera preparing for them? Here is the deep mystery. Some are talking of a 125 Single with rotating disc, others are sure of orthodox two-stroke Twins. loi
