after many months of researching, buying parts, and researching more, i finally found out what was causing the coughing on cold start riding. before i tell what the cause was, i want to tell y'all, that i did upgrade to the 25 deg. injectors. that did not fix the problem.
next thing i did was use propane to try and find a intake, or head gasket leak. ...no leaks. i changed the engine temp. sensor, new spark plugs, and i even considered a re- map of the ecm, as my last resort.
a couple days ago, i was reading here in the forums, and found a thread that touched on the subject of exhaust flanges. the thread quickly turned into a discussion about fuel injectors. the discussion about the exhaust flanges was very minimal.
low and behold, the problem WAS the exhaust flanges, at the motor. both were loose. i tightened all four flange nuts about 3 turns each. damn thing is, i didn't hear any exhaust leaks. i started the motor, warmed it up, and tighten all four one more time. i didn't ride the bike right away, because i wanted to ride it from a cold start. the next morning i was excited to take that ride ...
i started the bike, put it in gear, and rode down the road. i knew instantly it was fixed. i knew, because all the times before, the bike would cough through the intake, before i got 500 feet down the road. i am soooooo happy to say - my ironhorse is running great, and no longer has the problem. it even seems to be running better overall.
advice to all - tighten your exhaust flanges every time you do a oil change. i would also recommend buying stainless steel nuts, and lock washers, to replace the rusty steel factory nuts.

 

Not a bad idea to keep a couple of spare flange nuts either. They are an odd thread size if I remember correctly. If you lose one on the road, finding a replacement may be difficult.

 

great advise on the extra nuts.
i would say, if you want to know what bolts, or nuts are going to come loose most often, it is going to be anything to do with the exhaust.
... i would have never expected something so simple, to be the problem with coughing/spiting. i forgot to mention, after the bike warmed up, the coughing would stop. this should have been my first clue, that something was leaking when cold,but sealing, after the bike was hot. =/
i assume the exhaust flange was letting air into the intake area? making it starve for gas, or run too lean?

 

Yes, sucking air and leaning out the a/f. That was a pretty elusive fix for a cough. Good work chasing that one down.