[goodquest]

What year is your 450?
2006

And what have you done as far as MOD's?
Opened air box, pipe, 168 Main jet, 48 pilot, NCVS needle, O-Ring Mod and smog Block off

Your pilot is a little too large. Try a 45 or even a 42.
Adjust the fuel screw this way and the bike will tell you what it wants for a pilot,

Setting the fuel screw mixture-
Try adjusting with the motor fully hot, and turning the fuel screw inwards until the idle slows or runs rough, then turn outwards 1 1/4 turns from this position. For example, if the idle slows or runs rough at 1/2 turn, then set the fuel screw to 1 3/4 turns out (1/2 + 1 1/4 = 1 3/4).
I did follow this, same results

See- http://www.pbase.com/jdjetting1/image/82894252 to understand how the fuel screw can affect the idle speed and air/fuel mixture at idle. The target range for the air/fuel mixture is near 12.5 to 13:1 at idle.

[goodquest]

Everything I've read to this point I agree with. You mentioned one thing that raised my ears a little. You said that you can rev is 6 times without issue then the 7th it would flame out.
While you have the bowl open. Make sure that your floats are not stuck creating a false lean condition.

I will once I have the carb open