Well, gentleman, and ladies if you are in attendance as well, what we have here, I believe, is a fueling problem. My suspicion, coming from years as an auto tech, is that Yamaha has made the air fuel ratio pretty lean at idle. This is a great city commuter bike and that makes sense to save a little extra fuel at stop lights to increase mileage.
If anyone here has ever had a carb'ed vehicle, you may remember when the air fuel mixture is lean and you hit the throttle, it stumbles or even dies. When the mixture is too rich (too much fuel) it accelerates fairly smooth, but a little slow, like its down in power.
This is exactly what happened on the Ninja 250 R when it was cold. That bike was a little lean from the factory to get excellent fuel milage. I had to wait for that thing to warm up for 10 minutes or it would stumble and die. I put in a dyno jet kit to increase the fuel amount and the problem disappeared completely. It never stumble and died again.
I think that's what needs to happen here. A reprogram to bump up the amount of fuel at idle. When we blip the throttle, the already lean mixture is getting a blast of air and not enough fuel and stumbling, or in my case and many others, is dying.
Yesterday, I put my FZ-07 next to my 2007 SV650SA (17k miles) and I blip the throttle on both the exact same. The SV instantly jumps to 3k-3.5k rpm furosciously without any hesitation. The FZ kinda seems totally anemic and only kinda slowly goes up to 2k-2.5k rpm. A world of difference! I should make a video because the contrast is so drastic.