You can synch the carb with a synch tool if you want. There is also a glass buble on the, I believe, the left side of the carbs. You adjust the synch with the big screws on the boxes that sit on the carbs... the tors. Then you set the idle by adjust both screws at the same time to keep the in synch.
It's most likely not your problem. Could be a few things. I'll list some.
Electrically the tors can shut down the ignition source. YOu can unplut the tors system by unhooking the little black box under the tank on the left side.
There is also a parking brake switch on the left side. It's there to keep you from reving the engine while it's parking brake is on. You can check that it's working properly or simply disconnect it also.
If it's been torn apart it could be an airleak in the carbs, choke tube between the carbs, slides in the wrong carbs... swapped left and right, etc...
Oh yeah and most people run 32:1 to 40:1.