backfire when cold.

[locutus]

got a 91 electra glide. when starting, i pull out the choke, let warm up and drive off. i get a backfire, almost like the bike is starving for fuel. i've made sure the petcock is all the way open, and wind up giving it a little more choke. after the bike warms up it's fine. i tried some seafoam in it, and it seemed to help until the next tank of gas. any ideas?

 

[glider]

How about a rejetting? Maybe the low speed jet could use one size bigger to eliminate this.

 

[locutus]

i thought of that, but i wonder why this is starting now? it never had this problem before the only thing done to the carb recently was a new choke cable.