Vespa 125 ET3 125 PK125 Polini Race 133cc 135cc Cylinder Head

Single cylinder head that comes from the revised classic Polini Mono grey cast iron cylinder. This cylinder, now called "Racing", has a new head layout

So the new cast aluminium head has additional cooling fins on the lower side. This way the heat is dissipated much better, both from the cylinder itself and from the head.
The combustion chamber is now no longer supplied with a cast surface but has a finely machined finish. The squeezing surface as well as the compression have also been revised. The new copper gasket not only conducts the heat better but also contributes to a much better sealing between cylinder and head.

The head fits of course also on the conventional Polini grey cast iron cylinders with 133cc.