gs headgasket problem ?

[TCAT]

Hey guys...new around here but not new to bike.

91 gs500 former cra racebike, been sitting for a few years due to the previous owner thinking it was a carb issue and I'm thinking its more. after cleaning and sync'in the carbs it still won't pull vaccum..hangs up in,the rpms...we sprayed along the base of the cyl on the left side and it picks up rpms? Headgasket bad?