BIG EVOLUTION CRANKCASE for HORIZONTAL YAMAHA MINARELLI ENGINES

The Big Evolution crankcase for Horizontal Yamaha Minarelli engines presents two
main features. The most important one concerns the primary gear with variator driven
pulley.
Polini Motori has projected a further working on the case so that it is possible to fit the
supplementary gear that works on a pin to be screwed on the shaft itself. Thanks to
this, the pin is less flexible while usually it is completely overhanging .
Second important feature is the creation of air intakes on all the surface to improve
the variator cooling.
Thanks to these technical innovations it is possible to eliminate the vibrations
Minarelli’s variator and it is possible to exploit the entire belt travel on the variator.
It is worked in Italy and it is recommended for race purposes.
Item: 170.0306