- 47.6 mm bore - 39.3 mm stroke -> 70cc
- 52 mm bore - 39.3 mm stroke -> 84cc
- 52 mm bore - 44 mm stroke -> 94cc
These are the “big brothers” of Polini’s Evolution 3. Five massive transfer ports and a T-shaped exhaust port make up the basic layout. Compared to the 70cc version, performance is naturally even more extreme, just right for drag races.
Concerning workmanship, of course Polini offers the very best materials.
To be able to mount the Big Evolutions, machining of the engine casing is necessary. Due to the increased bore diameter, the spigot is larger. Therefore, adjustments need to be made.
If you are going all-out and plan on combining your Big Evolution with a long stroke shaft, the crankcase needs to be machined, too.