Honda specify BR9ECM for all NSR's except MC16.
http://tech.nsr-world.com/nsr/nsr-all/spark-plugs/
It's very difficult to pinpoint misfires unless the bike is running exact components as Honda intended. A bit like trying to sort carb issues when a bike's not running a standard airbox etc.
My advice is get it back totally stock (including reversing any wiresplice) and take it from there. As standard, every NSR works exceptionally well even if it only develops 40~45hp. If yours doesn't, then it's simply back to traditional fault-finding methods.
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Andy.
NSR-WORLD.COM
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