I have the stumble on my 13 but if I let it warm up so the temp needle moves a tick or two it's gone.
This tells me that the base map is too lean at warm up and would need to re-program to eliminate it.
But like I said it's not a problem because I let it warm up.
My 13 will do it when cold. Tried premium fuel, ecm reset, new plugs, nothing cured it. I know when it will happen(needle at second line) so I adjust how I apply throttle for the 10 seconds or so that my bike is in that mood.
2013 F6B in black of course
I got a red 13 like teach, yes she stumbles a bit, I just take off out of neighborhood and leave it in 3rd gear around 3K RPM for a while, she warms up fast!
I may be wrong but I believe our problem is CARB. They tend to be the strictest measure of everything. If you want to sell it in California, you must meet CARB requirements. There are more than a few people living in California so most companies want to sell there. All of my new lawn equipment runs terrible until they warm up. Once warmed up they perform brilliantly. I have a chain saw that needs a simple carburetor adjustment. They have very cleverly designed it so that only their unique tool will fit. It is against the law for me to own the tool. My point is - I think Honda has purposely mapped the cold engine fuel curve on our bikes at the ragged edge. I do not think Honda wanted to do this. I believe they were forced to do this. My motorcycle running to lean when cold is somehow compensating for your farting cow.
Damn Communists in Kalifornicate, Would bet Aunt Maxine or Aunt Nancy is the root cause.......