DR shoulhd get its own engine repaired if not then replaced with the same engine in fresher condition if that is also not possible then no one can avvoid alterations while putting some other motor in it..
Cagiva I am not sure, I think u r asking about same cagiva which came to sali kabariya and then he distributed alll over and many landed in rawalpindi... I have no clue about them but apparenly all I know is that putting an engine which does not have a spare parts availablity is a wast of money and time and labor.
best is to source an engine which can survive from ups and downs..