| Originally posted by andya |
The only thing that seems odd is that the face (where the back of the belts touch) of the tensioner pulleys is curved slightly as are the idlers.
This is called crowning, and although I am not particularly familiar with the Ducati belt drive, I can state that crowned pulleys are normal in automotive belt drives. The theory is that the crown centres the belt on back drive pulleys and helps it track correctly. (This theory is taking a pounding at the moment in my industry and we are now using machined flat pulleys.)