Does sound like a piston clearance problem, I know on the 600s they could come with either cast or forged pistons, which did make a difference to the Cold Clatter that went on. Also as we know with Ducati parts supply on the production line can be an issue so although barrells and Pistons usually have there markings Matched A to A or B to B there may be some that aren't Checkout the Desmo Due Paddock on Facebook |