Join Date: Apr 2014
Location: Enid, OK
I Ride: 2007 V-Star 1300, 2014 ZX-6R, 1986 Yamaha YZ250 (bored & stroked - 2 stroke)
Ugh, this isn't ever an easy thing to diagnose. The issue that you're having is a secondary effect, and it could be caused by about a dozen things.
But before I start giving you things to go check, here is what I believe is happening. The main symptom of the problem is a poor air/fuel ratio at lower rpm (and possible throughout the whole range). It isn't necessarily going to be bad enough to notice while idling without moving, but, as you are riding and let off the throttle, the rapid air pressure change in the intake box makes the air/fuel ratio go so far from ideal that it doesn't make enough power to keep the engine running. By increasing your idle speed, it just means that when you let off the throttle again while moving, the engine still generates enough power to continue running; however, there isn't correcting the main problem, just treating the apparent symptoms.
Anyhow. As already said a few times, you should check that your throttle bodies are sync'd.
Beyond that, I'd force the subthrottle to stay open and make sure that isn't an issue. Check that your inlet air temp sensor is reading properly, IIRC it is an RTD so you'll just need an ohm meter and another temp probe that you trust. Same thing with the inlet air pressure and atmospheric pressure sensors.
And then....fuel pressure could be bad, either because the pressure regulator, fuel filter, or the pump itself is having issues.
I too believe it's your A/F ratio. My bike has done it for a while after I messed with my map on my Bazzaz. I have a map switch so one is leaner than the other and my other map doesn't do it. Exactly like how you describe it.
However, since your bike is stock, I couldn't tell you. Something along the lines of what Steel said
2014 ZX-6R 636: M4 Street Slayer Exhaust, FlashTune Bike Tuning Kit, Bazzaz Z-Fi, Z-AFM, MJS Headers, K&N Race Air Filter, RaceTech Gold Valve Fork Kit w/ Bottom & Top-Out Mod, reshimmed & RT Fork Springs, RaceTech Gold Valve Shock w/ Refreshed internals & RT Powdercoated Lime Green Spring, D.I.D Gold Chain, Vortex -1 front sprocket, PMP Sprockets Anodized Green +2 rear aluminum sprocket (-1/+2), GPVR4, Fender Eliminator Kit, MotoDynamics Smoked Integrated LED Taillight, '13 Lower Green Fairings, R6 Throttle Tube, Pro Grip Padded Tank Pad, Stomp Grip Clear Tank Pads, Pazzo IFX Candy Green Shorty Levers, Raskal Graffiks Wheel Decals, Puig Double Bubble Dark Smoke Windscreen, Driven Block-Off Plates, Driven Gold Spools, Morimoto Mini H1 7.0 Bi-Xenon Projectors, Morimoto 5Five 50w 6000k HID's, (6) Morimoto XC RGB Angel Eyes, Pirelli Diablo Rosso Corsa's, etc...