Odd running

A correspondent with an Alp 4.0 is travelling through Spain and has complained of rough running of the engine. He feels it is something to do with ignition but can't be sure. The engine runs but at a certain rev range it's noisey. A mechanic he saw suggested that the CDI needed reprogramming. This seems a bit unlikely as it's doubtful if the ignition on this sort of machine is reprogrammable, and why should it change?

My suggestions of things to look for were:

1. The microswitch on the carb butterfly valve - what happens if this is jammed?
2. Open circuit plug cap - I've had this problem on other bikes and it is a pain
3. Over-oiled airfilter causing richness
4. Excess oil in the sump causing fouling of the air box
5. Open drains in the airbox causing loss of vacuum
6. Loose connectors or water throughout the circuit
7. Foreign object in the float bowl

Other possibilities were:

1. Improperly seated kick start lever partially engaging the ratchet
2. Timing chain or tensioner problem
3. Lack of tappet clearance
4. Something, anything (sump guard, bit of fairing, luggage etc etc) vibrating
5. Loose engine bolts
   

I hope I'll hear what the problem is so I can be aware of it...