Cylinder Polini for vespa evolution 2 d.58 135 cc

The new Evolution 2 kit is specific for racing on track for the Vespa Class 135cc
category.
The main feature of this new cylinder is the fitting that has been studied to work both
in the original position and in the "turned" position often used during the races on
track. This positon also favors the development and assembly of the muffler. The
engine has more power at every rpm.
The "Evolution 2" kit with rotary valve induction can be fitted in all the 125 Vespa with
crankshaft that has same measurements as the original one. It’s also available a Polini
balanced crankshaft, part no. 210.0033 with its connecting rod milled from a block,
that maintains the original 51mm stroke.
TECHNICAL FEATURES
Cylinder cast in aluminium, with bore of 58mm. to reach a displacement of 135cc.
The liner with Nickel-Siliceous coating improves the piston sliding, its resistance to
wear and abrasion.
The transfer ports are designed for racing. It has 6 transfers.
The piston is gravity cast in light alloy and it has two S10 chromed cast iron rings.
The head is cast in one piece only and some fins have been made under the head
plane in order to improve the heat dissipation. The compression ratio has been
studied to achieve the best performance.
Since this is a cylinder kit specific for races it is very important to proceed with a
careful set up of the bike and to fit it is compulsory to bore the crankcases.