fuji,
I can't speak of the CNS carb, I'm running the stock one. After I got the jet size correct with a good aftermarket aircleaner and CE billet intale(very short), the bike was great, No bog whatsoever. I took that motor and put it on an Aluminum frame MTB, I had to use a "Offset intake due to clearance issues and a stock aircleaner, lost over 3 MPH and throttle response is much slower(Longer intake runner). I'll use it that way for now. Just goes to show that even small changes make a difference.
Mac