I have heard that the early ST2 (1999) used to snap the rear engine bolts and that they were upgraded to 12mm from 2000. I think there was a frame colour change (to Silver) for the ST2 at the same time which identifies the larger bolt models.
As the water cooled 944 was probably the most powerful and heavy engine that frame housed up until then, it probably hadn't manifested before.
Ducati most likely made the modification across the entire range at that time to facilitate interchangeability and make way for more powerful engines which were in the pipeline.
The change would definitely have been applied to the 2001/2-on "ST" type Monster frame with the rod suspension link.
Intermediate hoop models (2000-2001) might be a mixture?
I'm sure I have a spare engine bolt somewhere but no idea what diameter.. Hang on...
