Motorcycle Repair: Fuel system, rich fuel mixture, fuel starvation

Question
I have a non model specific question. My bike starts easily without the use of the choke. After it gets warmed up it accelerates well but, at cruising speeds it begins to sputter. Rpm range @ 3000 to 3500 is the worst. Any ideas where to start?

Answer
Dave, try applying a little choke when it acts up.  If the engine runs better you're looking at a fuel starvation problem. If it doesn't improve you're looking for a ignition problem or an overly rich fuel mixture.  You can eliminate the overly rich mixture issue if you can turn the fuel off while you are riding and it will run better for a little while until the bowls get too low on fuel. If it runs better for a little while once you turn the fuel off, the carbs are too rich.

Regards
Rich