Smoking extruder.

I have almost finished my reprap, just when I turn my extruder on and let it get up to temperature. Around the 150C mark it starts smoking if I put my fan up against it it stops smoking but then the heat doesn't rise about 140-150.
I am pretty sure it is the tape that is burning. I have the kapton tape insulating the resistive wire and holding it on the brass piece.

I think there is insulated wire that is recommended but when I looked for it i couldn't find it anywhere.

It is normal for an extruder that is very new to smoke/steam a little when it is first used, and it may do so for a few minutes. Kapton tape is in fact nonflammable at that temperature, that's why it is used there. However it is possible that your wires' insulation is melting, but if it is a kit and you used the correct wire it is very unlikely.