QUESTION:

What are the different reasons that a carburetor would be back firing. I do not mean the popping on decel. I can hear the carbs popping through the air filters and there is hesitation. fuel mixture might not be right. It is very difficult to start with or without the choke. I have to open the throttle to get it to start. and it won't idle very well.

Carb popping causes:
1. vacuum leak
2. carbs need to be synched
3. carbs need to be cleaned (AGAIN)
4. fuel mixture is not right

These carbs were recently rebuilt at a local shop, and sadly, I don't trust the work from most any shop.
I have not rebuilt Triumph carbs, but I have rebuilt Honda Goldwing carbs, and Honda 750 carbs. So, I don't think I would have a problem doing this if necessary. But where is the best place to get a carb kit and a how to?