I've read all 415 posts here so far. 1st let me say, if anyone is selling their FI tool, let me know, I'd like to buy it.
I purchased a leftover 2012 (got a great deal, couldn't pass it up). I am having the same issue as most of you, hard starting. From what I can glean off this thread, the idle mix is set too low from the factory. Use the FI tool to richen it up. I suggest that we may have multiple problems that overlap into the same issue, hard starting.
I have owned an '06, '07 and now this '12. Both the '06 and '07 were hard to start when the battery was not at full charge. And I mean full. If I had been riding slow at low RPM's, the battery would not get a good charge and by the end of the day it would get harder to start. I believe it is because the spark is not as "hot" when the battery is low. This was especially true when the '07 battery started to go bad. The battery they come with is just enough to get the job done and no more. That is why I think some of you guys are noticing an improvement when you replace the battery with an aftermarket unit.
Now the '12 is tough to start cold or hot, but more so when hot. I just purchased the GYTR ECU and programmer and will be installing it later today. I would like to check to see where my idle number is set. I will adjust that number when I have time to tinker and test it. There could also be a third issue of gas quality and octane versus altitude. It sounds like a lot of us ride at higher elevations (I'd say 5000'+). This could be aggravating the issue if it is true what was said earlier in the thread about the ECU only changing its performance after starting and warming up, shutting it off, starting it, shutting it off etc. I don't remember the exact sequence, but you get the picture.
If you take into account all the different things that can cause a hard start issue, it can cause your head to explode. I choose to believe the idle setting and battery to be the leading cause and other problems are secondary. Any opinions?
And don't forget, I am looking to buy an FI tool. If you're done with yours, let me know.