Vespa Smallframe with Polini cylinder over 20hp
Today our customer John was once again on our Scooter Center test bench with his Vespa Smallframe.
Where can I find a few more horsepower in my Vespa engine?
More power for the Vespa
On his last visit, he had asked us what changes he could make to his engine to find a little more power. After briefly discussing what his current setup looks like, we were actually able to give him some tips on how to get more top performance.
Engine setup
Basically, the engine is equipped with a Polini Evo cylinder and a 54 bgm crankshaft. The 30 mm Mikuni TMX carburetor is fitted to an MRP intake manifold. The best prerequisites for becoming a clear over-20 unit. With additional machining of the exhaust and conversion of the Polini reed valve to 2-flap, the result is now as follows:
Even better with Kytronic
Due to the larger exhaust area, the exhaust can work much better. The small loss at 6500 rpm is unfortunately due to the lack of Kytronic. In its current state (red curve), a standard PK ignition system with an ignition timing of 18° from TDC does its job. With the
Kytronic it is certainly possible to shift the red curve 200 rpm to the left again, in the direction of earlier onset of power. All in all, a nice number - have fun on the road with it! (AS)