86 yamaha fz 750 giving me hell?

[Kjh]

ok here it goes i have a a 1986 fz 750 that has been giving me some trouble when the bike is wormed up and i come to a stop when i try to go it hesataes very bad for about 2 to 3 sec i anve checked the and cleaned the carbs checked and repacked the exhaust changed the plugs and went through the wiring system but cant fig out when is wrong but it only does it in 1st and only when u r just starting out the only things i have not done yet r change the coils and sync the carbs i know the coils could do this but id like to go the cheaper rought first would the carbs out of sync make this prob. so any help would b great thanks to all that take the time to help