It shouldn't get any hotter than 280-290. If it does you run the risk of damaging it.

Are you sure you don't see any smoke? It's running at a pretty good temperature. You could even lean it out a bit more because you have some room to play with.
Hmm maybe you just don't have your smoke seeing glasses on? Put those on and let us know how it works for ya.

Here's a suggestion, by the way you worded the question you see smoke at lower speeds but not during a high speed run?
If that's the case you could probably lean out your low speed needle and richen the high speed needle a little bit. You may want to wait for someone else to reply though because I'm not all that sure about that.