Shimming
 

Noticing on my bike as it is in pieces yet again, that the shims in each carb are located in different slots on the needle.
Now combined with the motorbike making a hell of alot of popping and spitting noise lately out of the exhaust could this be the problem?
Also any advise on where to put the shims in this case as I'm presuming with the motorbike popping/spitting it is running lean?