Carb, spark, or fuel problem. I don't know whitch?

[X-ray]

Hello to you all in gs wonderland!
Forgive me for my inability to post or type accurately but this is the first time i've used a message board.  yea yea i know, welcome to the information age.....
     My Gs, wich i aquired last Sept. to learn to ride on, has a couple of issues.  I'll stick to the main one.  It doesn't want to run.  I went to ride it today and the idle, with choke on full, was 1200RPM.  Usually it's 4000RPM.  If i gave it throttle  it would almost stall then slowly inch up to, but not exceed, 4000RPM even under full throttle.
     Now occasionally I would hear a "TST" sound coming from what I assumed was the carbs.  In a wouderfull display to show my ingnorance, I pulled the spark plugs and they appeared a deep red.  Feeling adventurous (spelling?) I removed the gas tank and air filter.  The filter need replaceing badly but there was, what I assume, old varnished gasoline in the bottom of the airbox.  The slick was comming from the right carb.
     Now my questions are:
1. Are the carbs in need of cleaning and if so what will i be getting my self into?

2.  Is my bike running lean, rich , or other because of the condition of the plugs

3. Why is there gass entering the air box when air should be rushing in?

           Thanks for any input!!