Originally posted by afm
Sirio Evo 2's only come with the new big diam. blue head with the sirio logo printed all over the head.
This engine is different than previous small head Sirio S12 in that it has more agressive sleeve and crank timing and better carb.
SG shaft is the one that has inside thread to hold clutch with Allen bolt, vs. the threaded shaft, that has the thread on the outside to hold clutch with a nut.
SG shaft is the way to go for Centax type clutch, and threaded for the standard type clutch.
AFM
you´ve got pm