We don't really do jetting advice in this section of the forum, but it does sound like you're running a little rich there, which may be why its running cool.

What colour are the plugs? I'm guessing they'll be black and oily, rather than tan / biscuit and definitely not white!

Has the engine been modified in any way?

If you become a supporting member we can offer much more specific advice in the NSR open discussion forum.