New Benelli 500 "Four"
CARLO PERELLI
THE BENELLI "FOUR," which Renzo Pasolini rode to a winning debut at Modena and set the fastest lap of the day two weeks after at Riccione (finishing second to Agostini in spite of brake fade), is a full size 498cc job. It was built in a few weeks, shortly before the opening of the 1967 season.
It is derived from the latest 350cc model, with four inclined valves and one central plug per cylinder. This feature proved exceedingly gOod also on the 500cc, not so much to obtain more bhp, but because it offered far better pulling power from the low rpm ranges. According to Signor Giovanni Benelli, boss of the factory and still a great enthusiast of racing in spite of his age, the "useful" rpm band of this new 500 goes from 8,000 to 12,800 (at which figure a power of 75 bhp is developed), while with an eight-valve head the power band would be much narrower, starting from 10,000. Moreover, contrary to what would at first appear, the 16-valve head arrangement is much more reliable, as proved by the 350cc model.
Following the typical Italian school in this field, the Benelli four has gear drive for the two ohcs, the primary transmission and the oil pump, drawing oil from the three kg capacity sump attached under the crankcase. The seven-speed gearbox is in unit and the multi-disc clutch runs externally on the left.
NEW BENELLI 500 "FOUR"
Rather unusually, the magneto is in front of the crankcase, bevel shaft driven from the crankshaft. Built in the USA for twostroke, four-cylinder, sports outboard engines and modified by Benelli, this magneto has always proven very reliable and better than other ignition systems tried .
With 3.00-18 (front) and 3.25-18 (rear) tires, the new Benelli 500 weighs only 297 pounds. With better brakes and a slightly reinforced frame to stand the higher horsepower, the Benelli people are sure to launch a severe challenge to Agostini's MV "three" and perhaps to Hailwood's Honda.
The next Italian events and the first world championship meeting will tell. ■
