BENELLI puller for BENELLI primary sprocket, BENELLI primara, steel, for excellent repair -1* rating for tuned engines Stefano BENELLI has been passionate about all petrol-powered vehicles, two or four strokes, since the 1980s. His love for the two-stroke is strong and above all for the Vespa. This is where he was able to gather his first experience in engine tuning and many of his developments saw successful use in scooter sprint racing. He found that the original Vespa gearbox was unable to handle the extra horsepower. Back when the only aftermarket gearbox component available here in Germany was a shorter 4th gear for the smallframe engine, BENELLI's range of gearbox components was already included in the scooters racing in the Italian national racing series. In more recent times, spare parts from various manufacturers have become available. Outside of its home country of Italy, parts produced by BENELLI were very difficult to obtain and only a small exclusive circle of racers and tuners were even aware of their excellent reputation and existence. During product comparisons conducted in Germany, its gear cogs were ranked better than those of other component manufacturers. Today the BENELLI company has grown into a small-scale manufacturer of high-end gearbox components using the best materials suitable for a wide range of potential uses. They have proven themselves in use on off-road, circuit and sprint racing machines. The simplest and most effective method of overall gear ratio adjustment is to replace the primary sprocket on the crankshaft. A basis for this conversion is provided by a primary drive with spur gears. Fine-tuning the smallest of the gears in the primary drive allows the reduction gear to be set precisely, to suit each stage of tuning. BENELLI gears are of the highest quality machined, hardened and made of special steel. Choosing the correct primary drive ratio depends on a number of factors: rated engine speed, gear ratios, area of ​​use and rear tire circumference. The primary gear ratio is determined by the number of teeth in the rack on both of its gears. A primary disk 72/24 gives a gear ratio of 3.00 and the higher the value (or quotient), the lower the ratio. BENELLI small series Vespa primary drive sprockets are suitable for use with the existing gear ratio and are also compatible with primary drives made by other manufacturers. BENELLI offers a variety of combination possibilities with the 24/72 and 27/69 primary drive gear sets. Bottom line: Once the primary drive is installed in the gearbox, it can be further refined by replacing individual gears. SIP-TIP: Don't forget to order the suitable primary drive gear from RMS, Surflex, Crimaz or DRT!