Sounds like you are on the right track. You need to get your hands on a multi-meter and check the voltage at idle and as the revs rise. Sounds like it could be electrical? Get some contact cleaner and start taking connectors apart and giving them a clean. Will help you get a good handle on the NSR electrics and give you a chance to do a bit of preventative maintenence.

One story I have heard....

Has your tank been lined with anything? Read somewhere of some of the tank lining lifting around the fuel pickup in the tank. Full tank, lining floats, as the fuel drops, lining falls over the fuel pickup, fuel starvation, poor running as a result! Just a suggestion while you have the tank off checking other areas!!

Good luck!