The 133 cc Polini Evolution is a completely new designed cylinder kit for use with the rotary valve induction. The alloy barrel is Nikasil plated.
The 57 mm bore gives 133 cc with the standard stroke. The port timings are 124° for the transfers and 179° for the exhaust duration. The basic layout is determined thru the six transfers. The transfers system is a complete new design compared to the cast iron 133 cc Polini kit. Here you’ll find much more port area. The transfer feeds are designed for the use with standard engine casings. A gate at the bottom can easily be grinded away to use the full surface area. Welding to the casings will be necessary then.
The exhaust port has a 38 mm width resulting in 68 % chord measurement. The exhaust studs are sized M8 and the distance is 56 mm. There is more than enough meat for further tuning.
The piston features two 1.5 mm thin steel rings. For improved running in the piston is coated. The alloy cast of the head has a high content of Silicone.
For further improved cooling it features fins at the bottom. This way the heat is dissipated much better from the head as well as from the barrel itself.
To evaluate products you need to be logged in.