What happened to my crankshaft

I drive Aprilia Area51 (minarelli) and on about 8000 kilometers crankshaft is gone 8P. First I thought that the thermogroup is gone but when I take apart, it appears that the crankshaft is problem. I have no idea why crankshaft is gone but thermogroup is intact.

I use Castrol TTS

few pics:

sorry for my english

looks like to much RPM and bad lubrication, a friend of me had exactly the same but he ran 45km/h with a laser at overkill RPM's

Aprillia SR said:

looks like to much RPM and bad lubrication, a friend of me had exactly the same but he ran 45km/h with a laser at overkill RPM's

Click to expand...

No clue at all. Scooter is all serial, not tuned. I used castrol tts. But now is it no more important, serial crankshaft is replaced with blue Topperformances : D