Flat spot at WOT

[scosgt]

So I have the 2012 SYM HD 200 EVO running really nice now.
I rode the parkway back and forth, no issues. Hit 67 on an upgrade, ran out of space but it had some more left in it, probably hit 70 with the 12g sliders, they do reduce the top end a few MPH.

However, at WOT there is a bit of a flat spot. Back off the throttle slightly and it accelerates, just not when held at WOT. The back off amount is like almost nothing, just getting it off the stop is all.

Is this possibly a throttle cable adjustment, or a carb adjustment, or?

No hesitation except at WOT when on the parkway or merging onto the parkway. Low speed accel is GREAT.

Any ideas?