4 stud, reed valve engine from Polini for Vespa Ciao, Bravo, Grande, Si, etc
These cases feature both 3 and 4 stud options so there are lots of choices there. They even left the rotary intake intact so you can block that off or use it. Comes with a block off plate for that.
This is for CDI, not points. You have to use the factory CDI or the Polini ignition with these cases.
These cases are set up for the 46mm kits. Can you use the smaller cylinders? Probably not. The transfers are massive! Designed for this kit specifically!
Comes with a bag of hardware, bearings, a seal, shims, the cases themselves, a big reed valves, and a gasket set.
Pair it with Polini's recommended 21mm carburetor.
From Polini themselves:
"Big news from Polini house, which adds to its already rich catalo gue the Polini reed crankcase For Race for Piaggio Ciao and Si. As per Polini DNA, the study and the production have the goal of increasing the performance, above all concerning the reed engines, which were born with limitations due to their original housing. The intake of the Ciao is very reduced and only Ø15 carburetors can be fitted: with the new Polini reed crankcase For Race it is possible to mount carburetors up to Ø21 with an adequate flow, which allows better performance and greater grit to the engine.
The crankcase is made of die casting aluminium and has been studied to fit both Piaggio Si and Ciao. Both models need the pedals’ removal. The SI does not require a modification for the engine housing, but the Ciao needs to slightly enlarge the original frame opening.
The new Polini reed crankcase For Race for Piaggio Ciao and Si allows housing both 3 and 4 stud cylinders, but Polini suggests using 4 stud cylinders. It is possible to assemble the new engine crankcase with the original electronic ignition, but Polini suggests using its own and full circle crankshafts. The carbon reed valve has 4 petals, while the rubber manifold can be fitted both on Polini CP or DellOrto PHBG carburetors."