What carbs do you have?
Usually you have throttle stop which will control the idle and tht is usually found on the clutch side below the throttle arm where the cable ends. There are also two mixture screws - on for each carb, usually found on the top of the inlet into the carb rubbers, quite often they can be under caps or blanks. These alter the mixture that the carb lets through - screw in for lean, out for richer. The setting for these are often referred to in "turns" this refers to amount of turns out from the idle screw being fully turned in. Be careful as these are brass and are very easily damaged.
As for balancing your carbs. You can use the dead cylinder method, which involves pulling a plug on each side and getting the engine to run evenly on one cylinder. Alternatively you will require crb balancing gauges or a manometer, which can be made yourself.
For all of the above, if you use the search feature for key words such as manometer, or look in the tech section and you will find what I think is the best written carb guide ever!
