Above,some of the Benelli 750 sei engine parts: I needed new timing chain,new primary chain, new gear selectors,two new gears,clutch assembly parts and most of all all bearings,seals and gaskets.
Suspecting anything relating to the noise coming from inside the engine is anyone's guess unless you pull the engine to pieces. If the engine of your bike is nearly due for revision may be it is a good idea to carry on with reapair and some preventive work.
When my bike's engine had been pulled to pieces many parts needed to be replaced with only 26k showed on the speed clock.In case of noise coming from your bike.s engine it can be combination of few worn engine parts.
Also as I mentioned to you before you can contact Enrique of Spanish Benelli Club who lives in Valencia.