Novarossi Plus 12-3SCT/3ST
The Novarossi Plus 12-3SCT and ST have been upgraded to include an 11.9mm diameter crankshaft. The original version of this 2.1cc motor included an 11.5mm diameter crankshaft but for whatever reason it has been made larger and so the main bearings in both the standard and ceramic versions have also been updated. Now you know.
Source: Kawahara [kawahara-racing.co.jp]