Motorcycle Repair: card, suzuki gs550, engine throttle

Question
I just bought a suzuki gs550 1983.
When you start it, it starts great but you can't take it off choke or it dies. If the choke is on it idles fine until you give it gas. There was some rotten gas in the bowl. I Drained them and the tank. So do you think that the carbs just need cleaned or what?

Answer
Jason,
 Most probably.  The choke limits the air intake greatlyso the engine runs rich with a much higher precentage of fuel than air.  This will help a cold engine start easier.  If you give the engine throttle w/ the choke still on it will try to suck more air throgh the barrel but it can't because the choke valve is closed and it will run to rich and stall.  A proper ratio of gas and air is required to make the engine run properly.  Sounds like you are not getting enough fuel to be proportional to the air coming in when you open the choke.  This may be because of clogged jets, improperly set floats or sticking needle valve.  I would reccomend that you remove the carbs and clean and adjust them properly.
Here are some basics guidlines on setting up and cleaning them:
Make sure air/fuel adjustments are not the culpret, you'll need to experiment with these, trial and error, usually 1 and 1/2 turns out from seated. Be absoulutly sure all orrifaces and jets are clean and not damaged. Use ONLY compressed air and solvents to clean these, using a pick or wire could damage the precise venturi action that takes place. Carburators can get pretty complex and require tuning from time to time. In addition there are different systems and effects that come into play at different throttle positions. Performance can be fine at one throttle position and terrible at another. All you can do is look closely for damage and carefully adjust all tolorances according to a good service manual. Do not overlook the float level and condition of the needle valve, be very sure you are not starving for fuel. In relation make sure fuel flow is unobstructed and use a good in-line fuel filter from the tank to the carb. Even tiny particles in the fuel can get logged in critical areas and cause havoc.

Hope this helps, Mike