Float height is 13mm
http://tech.nsr-world.com/nsr250/all-nsr250/nsr250-stock-carb-settings.php
You have to fall back to the MC16 specs on that page to find it.

Some relevant threads:
http://nsr250.net/forums/viewtopic.php?t=5322
http://www.nsr250.net/forums/viewtopic.php?t=9052
Hope that helps.
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[color=#808080][size=9]Yes,.. I too know how to waste Time and Money,...