Motorcycle Repair: Carburetor tuning, yamaha vmax, vacuum pressure

Question
Hi,
I have a 1988 Yamaha Vmax that needs carb. synchronizing. The bike is very out of synch and the idle is off. I don't know how to begin adjusting. I set the idle and while trying to synch the carbs, the idle changes. I fix that, it goes out of synch. Is there a way to find a starting point physically on all those screws?
Finally, I can synch all the carbs, but the vacuum pressure is low on all. What could this mean and hwo can I raise them all?
Thanks a lot.

Answer
Down draft carbs work great when working but when there are not they are about as good as a paper weight.I would suggest taking the bike in for a sync.It is worth the 1/2 hour labor that you are going to pay.....they are a head ache....glad i could help