Next Vespa Bravo upgrade, a Polini Speed Engine. A very nice engine case with enlarged intake and bored to accept 46 mm cylinder kits. Nothing you can’t achieve on a stock engine case, but i got it for a good price from my friend Nikolaj.
I bought a special intake manifold from Italy, made for a 15-16 mm SHA instead of the normal Piaggio SHA 13 mm carburetor.
I mounted the engine with a used original crankshaft, new bearings and seals. The intake opens 130° before TDC and closes again 51° after TDC, giving me a total duration of 181°. Good for many of the cylinders that are out there.
The setup will be:
- 46 mm Polini cylinder kit
- Dellorto SHA 16 mm carburettor – changed to 13 mm
- Proma Circuit exhaust – changed to Sito
- Polini variomatic – changed to non-variated
Stay tuned for future updates!
Last update, the Bravo is done for now, onboard video:
4 Replies to “Polini Speed Engine”
Why did you go from vario to mono? Why would I choose one over the other?
I had some vibrations from 60 km/h and up, from the vario system. Got tired of it, of course i miss the acceleration. Mono is cheaper by a lot.
Why 16 –> 13mm
I couldn’t fit a good airfilter/silencer, only the metal mesh, so it was too loud. And i couldn’t feel a great difference in performance.