I´ve heard cagiva can be unreliable in continous supply of spare parts.
Example, Husqvarna is owned by cagiva, here in France many sell their bikes cause cagiva have decided to stop providing spares for some recent models.
Except with husqvarna, I don´t have any experience in buying cagiva parts.
Anyhow if you like it, go for it.
Engine will be less reving than a 250cc and torque will be available more widely over the entire range.
A big single consumes the less fuel when torque is on it´s highest in range, now don´t confuse power and torque!
Example, my 600XTZ has the torque peak at 5500tr/min, this is where the engine functions the best and is freeing up every newton meter from fuel !
On a cagiva I don´t know, but it should be something similar, check the diagram in the owners manual.
Me, when I drive, I stay between 5000 and 6000 tr/mn.
You can go two up; put correct tyre pressure, screw monoshock spring tighter etc.
[This message has been edited by Matt595 (edited 10 February 2005).]