New to me 13. Had on a gutted stock muffler. Replaced that with a hmf slip on. I was having some issues with quick reving or stabbing the throttle, it would hesitate or bog down. To my knowledge the exhaust is the only thing done. It has the Mimi I carb. The jets that are in it are 152.5 A 55 and a 42.5. What should I upgrade to to bet better performance out of it?