Help with throttle cables

[Manaminal]

I recently put new handle bars on. There closer then my previous. I have plenty of slack in my cables. My throttle doesn't snap back and its stiffer to accelerate. I tried to sand down the paint on the new bars hoping that maybe that would help. Is there a way to adjust the cables other then by the grips. It's fuel injected 2007 Vulcan classic 1500. Any ideas or help would be appreciated.