Motorcycle Repair: rough running until warm up, several miles, sportster

Question
QUESTION: Mike, I have a 1989 sportster with 10,700 mile on it. I have had it for 2 years now. Recently, it runs rough until it is warmed up. Basically, it starts up great, runs good for the first mile or so, then it runs rough for the next 6 miles or so..sputtering, bogging down, backfiring etc. then it runs great for the rest of the day after it has warmed up.  Is there an adjustment that can be made to relieve this portion of bad performance?

ANSWER: If you leave the choke about half way on and run it for a while until it warms up, how does it run?
Mike

---------- FOLLOW-UP ----------

QUESTION: I've actually tried that. If I set it at half choke or no choke too soon the sputtering gets worse and it has actully stalled, so I pull it to full chock until it is completely warmed up..this takes several miles. Is having to keep the choke on for that long normal?

Answer
Sometimes you have to. There are some bikes that are more cold blooded than others and it takes a while for the motor to completly warm up. It doensnt hurt anything to keep the choke on until it runs good. The only problem you will run into is if you forget the choke is on. If you leave it on you will foul a plug.
Good luck and happy riding
Mike