Going to post this here, because we really don't need a bunch of different threads about the same problem. Maybe the OP (or an admin) will be good enough to edit the title of the thread to "3rd Gens - Stumble on Accel" so that it is more correct. Why change the title? Because this apparently is not only on 2014's.
In our trip down to EOM last week, we hooked up in Virginia with BigOgre (MIke from the Isle of Long) for a couple of days of Skyline Drive and Parkway touring. When we got down to the Ashville, NC area we jumped off the parkway and rode up some squiggly lines on the map that called for some higher rpm. Plus it was getting warmer in the afternoon, as it is wont to do in the southlands.
When we stopped for a break, Mike said that he was experiencing the same problem that he had felt when he was riding hard out west earlier in the summer out at the Red Lodge Rendezvous: As he tried to roll-on throttle the bike was hesitating to accelerate until suddenly it would "catch" and nearly shoot out of the turns. A light bulb went on over my head as he described this, and I told him that we'd be on some easy cruising roads for a while, lets see what happens to the symptoms as the bike cools down. Sure enough, the symptoms went away and are only appearing for him when the engine is highly heat soaked, like at the end of a good hard romp, or high speed highway running in hot weather.
I know this heat relationship is a classic TPS failure symptom both from my own first hand experiences and others' past reports. When the contact is first degrading it seems to come on when highly heated and then go back to normal operation when cooled off. Whether the symptoms occur at the first crack of the throttle or with the throttle in a more open position is going to depend on whether you do a lot of riding around town or out on the highway, as that will affect where on the TPS'es carbon track gets the most severe wear.
Discussing the possibilities on a 3rd Gen we've decided that, since the new bikes have Fly By Wire, either the APS (Accelerator Position Sensor) or the TPS (Throttle Position Sensor), which are very similar devices, could cause these kinds of symptoms. The trick will be to come up with a way to easily determine which of the two hundred dollar sensors is the culprit when it happens.
I suggested that when the bike is in the failure mode we may be able to use the cruise control to try and reproduce the symptom, and thereby eliminate the APS as a possibility (if you can reproduce it while on CC) since the ECU mostly ignores the APS during cruise control use. Unfortunately it will probably be hard to reproduce in situations like Mike's since it is happening at the first crack of the throttle, and cruise control has a minimum speed to engagement, but it still may be possible if you ride with the cruise on over hills steep enough that the CC closes the throttle fully. Just an idea...
I suggested that Mike bring the Bike to his dealership and explain the symptoms in detail as above, and also relay that he had the TPS problem on his 2004 many years ago and it was exactly the same. Maybe the dealership will be willing to try replacing the TPS rather than the entire throttle body per the FSM.
The main point of this (too long as usual) post is that Mike's bike is a 2015. So we now have reports of both '14's and '15's with apparent TPS issues.
Have any 2013s seen this issue yet? Maybe the TPS supplier was different, or the batch was unaffected, back in 2013?