Best thing to check your timing is with a timing light. You have a TCI though, not points, so the light will tell you if the TCI is bad, but you really can't adjust the timing like a points system. If it is the timing a diode may have gone bad in the TCI. This has not happened to me, but from what I have been told, and read, if a diode went bad your bike would not run. Although I would still check the timing with a light.
Sounds like it's not getting gas honestly, so...
Does it idle or do you need the choke for it to run??
Everyone will tell you as well, and it's a must. You need to check/adjust your cam chain tensioner, then vavles, then timing (but you have a TCI), then go to the carbs. So check these as well.
Are you petcocks clean? Carbs synched?
How are you getting the "3" turns out? There is a process called the "dead cylinder" method. It's in the carb guide. That's how you adjust the mix screw. There is no set recipe for these carbs. All are different.