THE PROBLEM YOU ARE HAVING SOUNDS LIKE THE CARB. I HAVE HAD ISSUES WITH THE BIKE YOU HAVE AND ON EVERY OCCASION TALKED THE CUSTOMER INTO INSTALLING A HYPER CHARGER JET KIT AND EXHAUST.
THAT ADDED ALOT MORE HORSE POWER,SOUNDS BETTER AND COMPLETLY FIXED ALL PROBLEMS.
IF YOU HAVE FOUND THIS ANSWER TO BE HELPFUL PLEASE CLICK ON THE ACCEPT BUTTON AND LEAVE POSITIVE FEEDBACK. THANKS