Since you resolved the choke issue, have you done much mileage?

I'd consider new plugs if it doesn't already have them, and just give it run. As others have said, basics for now - sounds to me like this choke would be the issue.

Whenever I have an issue with the carb and its cleanliness related, I like to strip them completely, check all the jets are clear and look sharp when held up to the light, record needle positions (check needles are stock size and shape!) count screw turns, and then reset to standard if possible and applicable (airbox, exhaust, port mods etc all change this) - I'm no expert on NSR's as I don't have mine yet but its worked for me on everything else, and I find it better both mentally and physically to to just do it once, and do it right, and then have the peace of mind knowing its done, and if the problem persists, confidently move along to the next potential issue. Once you know you've got your air and fuel right, having presumably checked the basic electrical already, I'd then be checking beyond plug condition, is the core in the HT corroded, are the caps in good nick, swap the coils, does the problem swap to the other cylinder etc..