I have a 2005 FSE450 with ducati flywheel/stator and i have M30x1,5 thread! In the partslist diagram the 2004 and 2005 have the same code flywheel, so it should be M30x1,5.
Just made my own puller
but GasGas part number for the puller is MFS400134045
Drawing if interested
https://drive.google.com/file/d/0B28...ew?usp=sharing