On a streamlined vehicle very similar to this (the Vespa 125 Circuit “alloy frame” of 1949) rider Dino Mazzoncini also performed brilliantly in track races, most memorably in the head-to-head between Vespa and Lambretta that took place on the Genoa Circuit (Corso Italia) and ended in a victory for Vespa in the motor scooter class.
Bore: 53 mm - Stroke: 56 mm - Displacement: 125 cc
Top speed: 136.92 km/h (average)
Suspension: front with coil springs and calipers shock absorber, rear with rubber pad and leaf spring shock absorber
Tyres: 3.00-10" (for races)
Text stolen from here.